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Purpose: This study characterizes intratumoral macrophage populations within baseline melanoma biopsies from patients with advanced melanoma who received either anti-PD-1 monotherapy or a combination with anti-CTLA-4. Particularly, FcγRIIIa (CD16)-expressing macrophage densities were investigated for associations with response and progression-free survival. Experimental Design: Patients with advanced melanoma who received either anti-PD-1 monotherapy or combination anti-PD-1 and anti-CTLA-4 were retrospectively identified. Macrophage populations were analyzed within baseline melanoma biopsies via multiplex IHC in relation to treatment outcomes. Results: Patients who responded to combination immune checkpoint inhibitor contained higher CD16+ macrophage densities than those who did not respond (196 vs. 7 cells/mm2; P = 0.0041). There was no diffidence in CD16+ macrophage densities in the PD-1 monotherapy-treated patients based on response (118 vs. 89 cells/mm2; P = 0.29). A significantly longer 3-year progression-free survival was observed in combination-treated patients with high intratumoral densities of CD16+ macrophages compared with those with low densities (87% vs. 42%, P = 0.0056, n = 40). No association was observed in anti-PD-1 monotherapy-treated patients (50% vs. 47%, P = 0.4636, n = 50). Melanoma biopsies with high densities of CD16+ macrophages contained upregulated gene expression of critical T-cell recruiting chemokines (CXCL9, CXCL10, and CXCL11). Conclusions: Our data demonstrate that tumor microenvironments enriched with CD16+ macrophages are favorable for response to combination anti-PD-1 and anti-CTLA-4 therapy but not anti-PD-1 monotherapy. These data provides a potential biomarker of response for combination immunotherapies in patients with metastatic melanoma.

To assess efficacy and toxicity of combination immunotherapy with ipilimumab plus nivolumab in routine practice in a retrospective multicentre cohort of patients with advanced melanoma.This retrospective analysis included patients with advanced melanoma treated with ipilimumab and nivolumab between October 2015 and January 2020 at six centres in Australia, Europe and the United States of America. We describe efficacy outcomes (overall survival [OS], progression-free survival [PFS] and objective response rate [ORR]) in treatment-naïve and pre-treated patients, with and without brain metastases, plus treatment-related adverse events (trAEs) in all patients treated.A total of 697 patients were identified; 472 were treatment-naïve of which 138 (29.2%) had brain metastases, and 225 were previously treated of which 102 (45.3%) had brain metastases. At baseline, 32.3% had stage M1c and 34.4% stage M1d disease. Lactate dehydrogenase was high in 280 patients (40.2%). With a median follow-up of 25.9 months, median OS in the 334 treatment-naïve patients without brain metastases was 53.7 months (95% confidence interval [CI] 40.8-NR) and 38.7 months (95% CI 18.6-NR) for the 138 treatment-naïve patients with brain metastases. For the entire cohort the ORR was 48%, for treatment-naïve patients without brain metastases ORR was 56.6% with a median PFS of was 13.7 months (95% CI 9.6-26.5). Median PFS was 7.9 months (95% CI 5.8-10.4) and OS 38 months (95% CI 31-NR) for the entire cohort. Grade 3-4 trAE were reported in 44% of patients, and 4 (0.7%) treatment-related deaths (1 pneumonitis, 2 myocarditis and 1 colitis) were recorded.The outcome and toxicity of combination immunotherapy with ipilimumab and nivolumab in a real-world patient population are similar to those reported in pivotal trials.

Anti-programmed cell death protein 1 (PD1) antibodies, pembrolizumab and nivolumab, alone or in combination with ipilimumab, have become standard treatment for melanoma and multiple other malignancies. Neurological adverse effects are rare and have not been well characterized to date. Patients who developed neurological adverse effects while being treated with PD1, alone or in combination with ipilimumab, were retrospectively identified from 10 cancer centers. Fifty-eight patients were included, and the median time from treatment initiation to development of neurological adverse effects was 7 weeks (range, 1-86.5 weeks). Thirty-seven (64%) toxicities affected the peripheral nervous system. Fifty (86%) patients were treated with corticosteroids, with 22 (37%) patients requiring further immunomodulation including intravenous immunoglobulin (16), plasmapheresis (7), mycophenolate mofetil (4), cyclophosphamide (1), and rituximab (1). Twenty-seven (46%) had a complete resolution of their neurological symptoms, and two (4%) patients died secondary to complications from their neurological adverse effects. The response rate of the cancer to immunotherapy was 78%, and the median progression free survival was not reached. Neurological adverse effects can occur with PD1 treatment, do not appear to impact treatment response, but may be irreversible or worsen in some patients. Management may require immunomodulation beyond corticosteroids.

PURPOSE Compared with people living without HIV (PWOH), people living with HIV (PWH) and cancer have traditionally been excluded from immune checkpoint inhibitor (ICI) trials. Furthermore, there is a paucity of real-world data on the use of ICIs in PWH and cancer. METHODS This retrospective study included PWH treated with anti–PD-1- or anti–PD-L1-based therapies for advanced cancers. Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS). Objective response rates (ORRs) were measured per RECIST 1.1 or other tumor-specific criteria, whenever feasible. Restricted mean survival time (RMST) was used to compare OS and PFS between matched PWH and PWOH with metastatic NSCLC (mNSCLC). RESULTS Among 390 PWH, median age was 58 years, 85% (n = 331) were males, 36% (n = 138) were Black; 70% (n = 274) received anti–PD-1/anti–PD-L1 monotherapy. Most common cancers were NSCLC (28%, n = 111), hepatocellular carcinoma ([HCC]; 11%, n = 44), and head and neck squamous cell carcinoma (HNSCC; 10%, n = 39). Seventy percent (152/216) had CD4+ T cell counts ≥200 cells/µL, and 94% (179/190) had HIV viral load CONCLUSION Among PWH, ICIs demonstrated differential activity across cancer types with no excess toxicity. Safety and activity of ICIs were similar between matched cohorts of PWH and PWOH with mNSCLC.

Guidelines addressing melanoma in-transit metastasis (ITM) recommend immune checkpoint inhibitors (ICI) as a first-line treatment option, despite the fact that there are no efficacy data available from prospective trials for exclusively ITM disease. The study aims to analyze the outcome of patients with ITM treated with ICI based on data from a large cohort of patients treated at international referral clinics.A multicenter retrospective cohort study of patients treated between January 2015 and December 2020 from Australia, Europe, and the USA, evaluating treatment with ICI for ITM with or without nodal involvement (AJCC8 N1c, N2c, and N3c) and without distant disease (M0). Treatment was with PD-1 inhibitor (nivolumab or pembrolizumab) and/or CTLA-4 inhibitor (ipilimumab). The response was evaluated according to the RECIST criteria modified for cutaneous lesions.A total of 287 patients from 21 institutions in eight countries were included. Immunotherapy was first-line treatment in 64 (22%) patients. PD-1 or CTLA-4 inhibitor monotherapy was given in 233 (81%) and 23 (8%) patients, respectively, while 31 (11%) received both in combination. The overall response rate was 56%, complete response (CR) rate was 36%, and progressive disease (PD) rate was 32%. Median PFS was ten months (95% CI 7.4-12.6 months) with a one-, two-, and five-year PFS rate of 48%, 33%, and 18%, respectively. Median MSS was not reached, and the one-, two-, and five-year MSS rates were 95%, 83%, and 71%, respectively.Systemic immunotherapy is an effective treatment for melanoma ITM. Future studies should evaluate the role of systemic immunotherapy in the context of multimodality therapy, including locoregional treatments such as surgery, intralesional therapy, and regional therapies.

PURPOSE Currently, there are no robust biomarkers that predict immunotherapy outcomes in metastatic melanoma. We sought to build multivariable predictive models for response and survival to anti-programmed cell death protein 1 (anti–PD-1) monotherapy or in combination with anticytotoxic T-cell lymphocyte-4 (ipilimumab [IPI]; anti–PD-1 ± IPI) by including routine clinical data available at the point of treatment initiation. METHODS One thousand six hundred forty-four patients with metastatic melanoma treated with anti–PD-1 ± IPI at 16 centers from Australia, the United States, and Europe were included. Demographics, disease characteristics, and baseline blood parameters were analyzed. The end points of this study were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The final predictive models for ORR, PFS, and OS were determined through penalized regression methodology (least absolute shrinkage and selection operator method) to select the most significant predictors for all three outcomes (discovery cohort, N = 633). Each model was validated internally and externally in two independent cohorts (validation-1 [N = 419] and validation-2 [N = 592]) and nomograms were created. RESULTS The final model for predicting ORR (area under the curve [AUC] = 0.71) in immunotherapy-treated patients included the following clinical parameters: Eastern Cooperative Oncology Group Performance Status, presence/absence of liver and lung metastases, serum lactate dehydrogenase, blood neutrophil-lymphocyte ratio, therapy (monotherapy/combination), and line of treatment. The final predictive models for PFS (AUC = 0.68) and OS (AUC = 0.77) included the same variables as those in the ORR model (except for presence/absence of lung metastases), and included presence/absence of brain metastases and blood hemoglobin. Nomogram calculators were developed from the clinical models to predict outcomes for patients with metastatic melanoma treated with anti–PD-1 ± IPI. CONCLUSION Newly developed combinations of routinely collected baseline clinical factors predict the response and survival outcomes of patients with metastatic melanoma treated with immunotherapy and may serve as valuable tools for clinical decision making.

The role of neoadjuvant therapy is undergoing an historic shift in oncology. The emergence of potent immunostimulatory anticancer agents has transformed neoadjuvant therapy from a useful tool in minimizing surgical morbidity to a life-saving treatment with curative promise, led by research in the field of melanoma. Health practitioners have witnessed remarkable improvements in melanoma survival outcomes over the past decade, beginning with checkpoint immunotherapies and BRAF-targeted therapies in the advanced setting that were successfully adopted into the postsurgical adjuvant setting for high-risk resectable disease. Despite substantial reductions in postsurgical recurrence, high-risk resectable melanoma has remained a life-altering and potentially fatal disease. In recent years, data from preclinical models and early-phase clinical trials have pointed to the potential for greater clinical efficacy when checkpoint inhibitors are administered in the neoadjuvant rather than adjuvant setting. Early feasibility studies showed impressive pathologic response rates to neoadjuvant immunotherapy, which were associated with recurrence-free survival rates of over 90%. Recently, the randomized phase II SWOG S1801 trial (ClinicalTrials.gov identifier: NCT03698019 ) reported a 42% reduction in 2-year event-free survival risk with neoadjuvant versus adjuvant pembrolizumab in resectable stage IIIB-D/IV melanoma (72% v 49%; hazard ratio, 0.58; P = .004), establishing neoadjuvant single-agent immunotherapy as a new standard of care. A randomized phase III trial of neoadjuvant immunotherapy in resectable stage IIIB-D melanoma, NADINA (ClinicalTrials.gov identifier: NCT04949113 ), is ongoing, as are feasibility studies in high-risk stage II disease. With a swathe of clinical, quality-of-life, and economic benefits, neoadjuvant immunotherapy has the potential to redefine the contemporary management of resectable tumors.

Background Immune checkpoint inhibitors (ICIs) have activity across many tumor types, but activation of the immune system may also lead to significant, often steroid-refractory immune-related adverse events (irAEs). We sought to determine the activity of tocilizumab, an anti-interleukin-6 receptor monoclonal antibody, in treatment or prevention of auto-immune irAE in ICI-treated patients. Methods Institutional databases from 2 melanoma centers were reviewed for patients treated with ICIs and tocilizumab. Longitudinal assessment of C-reactive protein (CRP) and assessment of clinical improvement or prevention of flare of pre-existing auto-immune conditions were utilised to evaluate the benefit of tocilizumab. Results Twenty-two patients were identified. Two were treated prophylactically. Twenty were treated for management of irAEs. Median time to irAE onset from ICI start was 48 days (range 8–786) and from irAE onset to tocilizumab 32 days (range 1–192). Median time to irAE resolution from tocilizumab was 6.5 days (range 1–93). Clinical improvement/benefit was demonstrated in 21/22 patients. Median CRP prior to ICI administration was 32 mg/l (range 0.3–99), at the onset of irAE 49.5 mg/L (range 0.3–251, P = 0.047) and after tocilizumab 18 mg/L (range 0.3–18, P = 0.0011). Tocilizumab was well tolerated with self-limiting and transient toxicities in 11 (50%) patients. From start of ICI, median progression-free survival was 6 months (range 3.9–18.8) and median overall survival was not reached. Conclusions Tocilizumab was a well-tolerated and effective steroid-sparing treatment for both management of irAEs, as well as prevention of flare of pre-existing auto-immune disorders. Prospective trials to evaluate its efficacy and impact on cancer outcomes compared with standard strategies are required.

Purpose: Overweight/obese (OW/OB) patients with metastatic melanoma unexpectedly have improved outcomes with immune checkpoint inhibitors (ICI) and BRAF-targeted therapies. The mechanism(s) underlying this association remain unclear, thus we assessed the integrated molecular, metabolic, and immune profile of tumors, as well as gut microbiome features, for associations with patient body mass index (BMI). Experimental Design: Associations between BMI [normal (NL < 25) or OW/OB (BMI ≥ 25)] and tumor or microbiome characteristics were examined in specimens from 782 patients with metastatic melanoma across 7 cohorts. DNA associations were evaluated in The Cancer Genome Atlas cohort. RNA sequencing from 4 cohorts (n = 357) was batch corrected and gene set enrichment analysis (GSEA) by BMI category was performed. Metabolic profiling was conducted in a subset of patients (x = 36) by LC/MS, and in flow-sorted melanoma tumor cells (x = 37) and patient-derived melanoma cell lines (x = 17) using the Seahorse XF assay. Gut microbiome features were examined in an independent cohort (n = 371). Results: DNA mutations and copy number variations were not associated with BMI. GSEA demonstrated that tumors from OW/OB patients were metabolically quiescent, with downregulation of oxidative phosphorylation and multiple other metabolic pathways. Direct metabolite analysis and functional metabolic profiling confirmed decreased central carbon metabolism in OW/OB metastatic melanoma tumors and patient-derived cell lines. The overall structure, diversity, and taxonomy of the fecal microbiome did not differ by BMI. Conclusions: These findings suggest that the host metabolic phenotype influences melanoma metabolism and provide insight into the improved outcomes observed in OW/OB patients with metastatic melanoma treated with ICIs and targeted therapies. See related commentary by Smalley, p. 5

PURPOSE Ipilimumab and nivolumab have each shown treatment benefit for high-risk resected melanoma. The phase III CheckMate 915 trial evaluated adjuvant nivolumab plus ipilimumab versus nivolumab alone in patients with resected stage IIIB-D or IV melanoma. PATIENTS AND METHODS In this randomized, double-blind, phase III trial, 1,833 patients received nivolumab 240 mg once every 2 weeks plus ipilimumab 1 mg/kg once every 6 weeks (916 patients) or nivolumab 480 mg once every 4 weeks (917 patients) for ≤ 1 year. After random assignment, patients were stratified by tumor programmed death ligand 1 (PD-L1) expression and stage. Dual primary end points were recurrence-free survival (RFS) in randomly assigned patients and in the tumor PD-L1 expression-level < 1% subgroup. RESULTS At a minimum follow-up of approximately 23.7 months, there was no significant difference between treatment groups for RFS in the all-randomly assigned patient population (hazard ratio, 0.92; 95% CI, 0.77 to 1.09; P = .269) or in patients with PD-L1 expression < 1% (hazard ratio, 0.91; 95% CI, 0.73 to 1.14). In all patients, 24-month RFS rates were 64.6% (combination) and 63.2% (nivolumab). Treatment-related grade 3 or 4 adverse events were reported in 32.6% of patients in the combination group and 12.8% in the nivolumab group. Treatment-related deaths were reported in 0.4% of patients in the combination group and in no nivolumab-treated patients. CONCLUSION Nivolumab 240 mg once every 2 weeks plus ipilimumab 1 mg/kg once every 6 weeks did not improve RFS versus nivolumab 480 mg once every 4 weeks in patients with stage IIIB-D or stage IV melanoma. Nivolumab showed efficacy consistent with previous adjuvant studies in a population resembling current practice using American Joint Committee on Cancer eighth edition, reaffirming nivolumab as a standard of care for melanoma adjuvant treatment.

Acral melanomas are a unique subset of melanomas occurring on the palms, soles, and nails. There is poor prognosis with surgery alone and no specific guidelines for the treatment of metastatic acral melanoma. This meta-analysis explored the systemic therapy outcomes for metastatic acral melanoma. Medline, Pubmed, EMBASE, and the grey literature were searched from 2010 to August 2020 for studies specifying the treatment outcome of metastatic acral melanoma. Studies were assessed by two investigators. A random-effects meta-analysis was performed and pooled Kaplan-Meier curves for progression-free survival and overall survival were created. Critical appraisal was performed using the Newcastle-Ottawa Scale. Nineteen nonrandomized studies were included, comprising 646 patients with acral melanomas and 1609 patients with nonacral melanomas treated with systemic therapy including chemotherapy, KIT-targeted drugs, as well as anti-CTLA-4 and anti-PD-1 checkpoint inhibitor therapy. Thirteen studies included Kaplan-Meier curves for progression-free survival or overall survival and 11 studies reported treatment responses. Patients with acral melanomas had worse prognosis than nonacral cutaneous melanoma (acral overall survival: median 15 months, 95% CI, 13.7-16.3 months; nonacral cutaneous: median 24 months, 95% CI, 22.6-25.4 months, P

Background: Dabrafenib plus trametinib has demonstrated clinical benefit across multiple BRAF-mutant tumours, leading to approval for resected stage III and metastatic melanoma, non-small-cell lung cancer (NSCLC) and anaplastic thyroid cancer. Pyrexia is a common adverse event in patients treated with dabrafenib plus trametinib. Here, we characterise the incidence, patterns and management of pyrexia in patients receiving dabrafenib plus trametinib in clinical trials. Methods: Patients (N = 1076) included in the analysis received dabrafenib plus trametinib in the following clinical trials: phase II registration trial in advanced NSCLC (N = 82), phase III COMBI-AD study in resectable stage III melanoma (N = 435) and phase III COMBI-d and COMBI-v studies in unresectable or metastatic melanoma (N = 209 and N = 350, respectively). Results: Among the 1076 patients enrolled in the clinical trials, 61.3% developed pyrexia, 5.7% developed grade 3/4 pyrexia and 15.6% developed a protocol-defined serious pyrexia event. Among the 660 patients with pyrexia, 33.0% had 1 occurrence, 19.8% had 2 occurrences and 47.1% had ≥3 occurrences. The incidence of pyrexia was highest early in treatment and decreased with time on treatment. Temporary dose interruption of dabrafenib or trametinib was the most common and effective management strategy. Conclusions: Pyrexia is the most common adverse event associated with dabrafenib plus trametinib but is manageable with dose interruption. Trial registration: ClinicalTrials.gov (Phase II NSCLC, NCT01336634; COMBI-AD, NCT01682083; COMBI-d, NCT01584648; COMBI-v, NCT01597908). Keywords: Adverse event; BRAF V600–mutant melanoma; BRAF inhibitor; MEK inhibitor; Pyrexia.

Introduction: In patients with metastatic melanoma, progression of a single tumour lesion (solitary progression) after response to immune checkpoint inhibition (ICI) is increasingly treated with local therapy. We evaluated the role of local therapy for solitary progression in melanoma.Patients and methods: Patients with metastatic melanoma treated with ICI between 2010 and 2019 with solitary progression as first progressive event were included from 17 centres in 9 countries. Follow-up and survival are reported from ICI initiation.Results: We identified 294 patients with solitary progression after stable disease in 15%, partial response in 55% and complete response in 30%. The median follow-up was 43 months; the median time to solitary progression was 13 months, and the median time to subsequent progression after treatment of solitary progression (TTSP) was 33 months. The estimated 3-year overall survival (OS) was 79%; median OS was not reached. Treatment consisted of systemic therapy (18%), local therapy (36%), both combined (42%) or active surveillance (4%). In 44% of patients treated for solitary progression, no subsequent progression occurred. For solitary progression during ICI (n = 143), the median TTSP was 29 months. Both TTSP and OS were similar for local therapy, ICI continuation and both combined. For solitary progression post ICI (n = 151), the median TTSP was 35 months. TTSP was higher for ICI recommencement plus local therapy than local therapy or ICI recommencement alone (p = 0.006), without OS differences.Conclusion: Almost half of patients with melanoma treated for solitary progression after initial response to ICI had no subsequent progression. This study suggests that local therapy can benefit patients and is associated with favourable long-term outcomes. & ordf;2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Purpose: Standard-dose pembrolizumab plus alternative-dose ipilimumab (1 mg/kg Q3W for 4 doses) were tolerable and had robust antitumor activity in advanced melanoma in cohort B of the phase 1 KEYNOTE-029 study. Cohort C evaluated standard-dose pembrolizumab with two other alternative ipilimumab regimens. Patients and Methods: Patients with treatment-naive unresectable stage III/IV melanoma were randomly assigned 1:1 to pembrolizumab 200 mg Q3W for ≤24 months plus ipilimumab 50 mg Q6W for 4 doses (PEM200+IPI50), or the same pembrolizumab regimen plus ipilimumab 100 mg Q12W for 4 doses (PEM200+IPI100). Primary end points were incidence of grade 3–5 treatment-related adverse events (TRAE) and objective response rate (ORR) per RECIST v1.1 by independent central review. Per protocol-defined thresholds, grade 3–5 TRAE incidence ≤26% indicated meaningful toxicity reduction and ORR ≥48% indicated no decrease in efficacy versus data reported for other PD-1 inhibitor/ipilimumab combinations. Results: Median follow-up on February 18, 2019, was 16.3 months in PEM200+IPI50 (N = 51) and 16.4 months in PEM200+IPI100 (N = 51). Grade 3–5 TRAEs occurred in 12 (24%) patients in PEM200+IPI50 and 20 (39%) in PEM200+IPI100. One patient in PEM200+IPI50 died from treatment-related autoimmune myocarditis. Immune-mediated AEs or infusion reactions occurred in 21 (42%) patients in PEM200+IPI50 and 28 (55%) in PEM200+IPI100. ORR was 55% in PEM200+IPI50; 61% in PEM200+IPI100. Conclusions: Pembrolizumab 200 mg Q3W plus ipilimumab 50 mg Q6W or 100 mg Q12W demonstrated antitumor activity above the predefined threshold; pembrolizumab plus ipilimumab 50 mg Q6W had lower incidence of grade 3–5 TRAEs than the predefined threshold, suggesting a reduction in toxicity. See related commentary by Jameson-Lee and Luke, p. 5153

Background Patients with synchronous clinical stage III melanoma can present with primary melanoma lesions, locally recurrent melanoma or in-transit metastases. Neoadjuvant ipilimumab plus nivolumab induces high pathologic response rates and an impressive relapse-free survival in patients with nodal macroscopic stage III melanoma. Whether primary site melanoma and in-transit metastases respond similarly to lymph node metastases with neoadjuvant immunotherapy is largely unknown. Such data would clarify whether surgical excision of these melanoma lesions should be performed before neoadjuvant therapy or whether it could be deferred and performed in conjunction with lymphadenectomy following neoadjuvant immunotherapy. Patients Patients with synchronous clinical stage III melanoma were identified from the OpACIN, OpACIN-neo and PRADO neoadjuvant trials, where all patients were treated with ipilimumab plus nivolumab. An additional case treated outside those clinical trials was included. Results Seven patients were identified; six patients had a concordant response in primary site melanoma lesions or in-transit metastasis and the lymph node metastases. One patient had concordant progression in both the primary and nodal tumour lesions and developed stage IV disease during neoadjuvant treatment, and thus, no resection was performed. Conclusion Pathologic response following neoadjuvant ipilimumab plus nivolumab in primary site melanoma lesions or in-transit metastasis is concordant with a response in the lymph node metastases, indicating that there may be no need to perform upfront surgery to these melanoma lesions prior to neoadjuvant treatment.

BackgroundAcral melanoma is a rare melanoma subtype with poor prognosis. Importantly, these patients were not identified as a specific subgroup in the landmark melanoma trials involving ipilimumab and the anti-programmed cell death protein-1 (PD-1) agents nivolumab and pembrolizumab. There is therefore an absence of prospective clinical trial evidence regarding the efficacy of checkpoint inhibitors (CPIs) in this population. Acral melanoma has lower tumor mutation burden (TMB) than other cutaneous sites, and primary site is associated with differences in TMB. However the impact of this on the effectiveness of immune CPIs is unknown. We examined the efficacy of CPIs in acral melanoma, including by primary site.MethodsPatients with unresectable stage III/IV acral melanoma treated with CPI (anti-PD-1 and/or ipilimumab) were studied. Multivariable logistic and Cox regression analyses were conducted. Primary outcome was objective response rate (ORR); secondary outcomes were progression-free survival (PFS) and overall survival (OS).ResultsIn total, 325 patients were included: 234 (72%) plantar, 69 (21%) subungual and 22 (7%) palmar primary sites. First CPI included: 184 (57%) anti-PD-1, 59 (18%) anti-PD-1/ipilimumab combination and 82 (25%) ipilimumab. ORR was significantly higher with initial anti-PD-1/ipilimumab compared with anti-PD-1 (43% vs 26%, HR 2.14, p=0.0004) and significantly lower with ipilimumab (15% vs 26%, HR 0.49, p=0.0016). Landmark PFS at 1 year was highest for anti-PD-1/ipilimumab at 34% (95% CI 24% to 49%), compared with 26% (95% CI 20% to 33%) with anti-PD-1 and 10% (95% CI 5% to 19%) with ipilimumab. Despite a trend for increased PFS, anti-PD-1/ipilimumab combination did not significantly improve PFS (HR 0.85, p=0.35) or OS over anti-PD-1 (HR 1.30, p=0.16), potentially due to subsequent therapies and high rates of acquired resistance. No outcome differences were found between primary sites.ConclusionWhile the ORR to anti-PD-1/ipilimumab was significantly higher than anti-PD-1 and PFS numerically higher, in this retrospective cohort this benefit did not translate to improved OS. Future trials should specifically include patients with acral melanoma, to help determine the optimal management of this important melanoma subtype.

Primary scalp melanomas are associated with a higher rate of brain metastasis than primary cutaneous melanomas occurring at other head and neck and body sites, but the reason is unclear. Spread to brain parenchyma via emissary veins draining from the scalp to dural sinuses has been suggested. We sought to examine the locations of metastases from primary scalp and nonscalp head and neck melanomas to determine whether there was anatomical evidence supporting direct venous spread to the brain. Data from patients who developed distant metastases from cutaneous head and neck melanomas (CHNMs) between 2000 and 2018 were analyzed. Anatomical sites of primary scalp melanomas and their respective intracranial metastases were compared. Times to first brain and nonbrain metastases were investigated for scalp and nonscalp primary CHNMs. Of 693 patients with CHNMs, 244 developed brain metastases: 109 (44.7%) had scalp primaries and 135 (55.3%) had nonscalp primaries. There was no significant association between anatomical sites of scalp primary melanomas and brain metastases (Cramer's V = 0.21; Chi-square P = 0.63). Compared with nonscalp CHNMs, scalp melanomas had no greater propensity for the brain as the first distant metastatic site ( P = 0.52) but had a shorter time to both brain metastasis (76.3 vs. 168.5 months; P0.001) and nonbrain metastasis (22.6 vs. 35.8 months; P0.001). No evidence was found to support a direct vascular pathway for metastatic spread of scalp melanomas to the brain. The increased incidence of brain metastases from scalp melanomas is probably driven by aggressive biological mechanisms.

Purpose: We evaluated the predictive value of pretreatment ctDNA to inform therapeutic outcomes in patients with metastatic melanoma relative to type and line of treatment. Experimental Design: Plasma circulating tumor DNA (ctDNA) was quantified in 125 samples collected from 110 patients prior to commencing treatment with immune checkpoint inhibitors (ICIs), as first- (n = 32) or second-line (n = 27) regimens, or prior to commencing first-line BRAF/MEK inhibitor therapy (n = 66). An external validation cohort included 128 patients commencing ICI therapies in the first- (N = 77) or second-line (N = 51) settings. Results: In the discovery cohort, low ctDNA (≤20 copies/mL) prior to commencing therapy predicted longer progression-free survival (PFS) in patients treated with first-line ICIs [HR, 0.20; 95% confidence interval (CI) 0.07–0.53; P < 0.0001], but not in the second-line setting. An independent cohort validated that ctDNA is predictive of PFS in the first-line setting (HR, 0.42; 95% CI, 0.22–0.83; P = 0.006), but not in the second-line ICI setting. Moreover, ctDNA prior to commencing ICI treatment was not predictive of PFS for patients pretreated with BRAF/MEK inhibitors in either the discovery or validation cohorts. Reduced PFS and overall survival were observed in patients with high ctDNA receiving anti–PD-1 monotherapy, relative to those treated with combination anti–CTLA-4/anti–PD-1 inhibitors. Conclusions: Pretreatment ctDNA is a reliable indicator of patient outcome in the first-line ICI treatment setting, but not in the second-line ICI setting, especially in patients pretreated with BRAF/MEK inhibitors. Preliminary evidence indicated that treatment-naïve patients with high ctDNA may preferentially benefit from combined ICIs.

The analysis of plasma circulating tumour nucleic acids provides a non-invasive approach to assess disease burden and the genetic evolution of tumours in response to therapy. BRAF splicing variants are known to confer melanoma resistance to BRAF inhibitors. We developed a test to screen cell-free RNA (cfRNA) for the presence of BRAF splicing variants. Custom droplet digital PCR assays were designed for the detection of BRAF splicing variants p61, p55, p48 and p41 and then validated using RNA from cell lines carrying these variants. Evaluation of plasma from patients with reported objective response to BRAF/MEK inhibition followed by disease progression was revealed by increased circulating tumour DNA (ctDNA) in 24 of 38 cases at the time of relapse. Circulating BRAF splicing variants were detected in cfRNA from 3 of these 38 patients; two patients carried the BRAF p61 variant and one the p55 variant. In all three cases the presence of the splicing variant was apparent only at the time of progressive disease. BRAF p61 was also detectable in plasma of one of four patients with confirmed BRAF splicing variants in their progressing tumours. Isolation and analysis of RNA from extracellular vesicles (EV) from resistant cell lines and patient plasma demonstrated that BRAF splicing variants are associated with EVs. These findings indicate that in addition to plasma ctDNA, RNA carried by EVs can provide important tumour specific information.

PURPOSE Improved understanding of the incidence, risk factors, and timing of CNS metastasis is needed to inform surveillance strategies for patients with melanoma. PATIENTS AND METHODS Clinical data were extracted from the databases of 2 major melanoma centers in the United States and Australia for 1,918 patients with American Joint Committee on Cancer (AJCC) 8th edition stage III melanoma, diagnosed from 1998-2014, who had (negative) baseline CNS imaging within 4 months of diagnosis. The cumulative incidence of CNS metastasis was calculated in the presence of the competing risk of death, from stage III presentation and at benchmark time points 1, 2, and 5 years postdiagnosis. RESULTS At a median follow-up of 70.2 months, distant recurrence occurred in 711 patients (37.1%). The first site of distant metastasis was CNS only for 3.9% of patients, CNS and extracranial (EC) for 1.8%, and EC only for 31.4%. Overall, 16.7% of patients were diagnosed with CNS metastasis during follow-up. The cumulative incidence of CNS metastasis was 3.6% (95% CI, 2.9% to 4.6%) at 1 year, 9.6% (95% CI, 8.3% to 11.0%) at 2 years, and 15.8% (95% CI, 14.1% to 17.6%) at 5 years. The risk of CNS metastasis was significantly influenced by patient sex, age, AJCC stage, primary tumor site, and primary tumor mitotic rate in multivariable and conditional analyses. High primary tumor mitotic rate was significantly associated with increased risk of CNS metastasis at diagnosis and all subsequent time points examined. CONCLUSION Similar rates of CNS metastasis were observed in 2 large, geographically distinct cohorts of patients with stage III melanoma. The results highlight the importance of primary tumor mitotic rate. Furthermore, they provide a framework for developing evidence-based surveillance strategies and evaluating the impact of contemporary adjuvant therapies on the risk of CNS metastasis development.

Detection of melanoma mutations using circulating tumor DNA (ctDNA) is a potential alternative to using genomic DNA from invasive tissue biopsies. To date, mutations in the GC-rich TERT promoter region, which is commonly mutated in melanoma, have been technically difficult to detect in ctDNA using next-generation sequencing (NGS) panels. In this study, we developed a custom melanoma NGS panel for detection of ctDNA, which encompasses the top 15 gene mutations in melanoma including the TERT promoter. We analyzed 21 stage III and IV melanoma patient samples who were treatment-naïve or on therapy. The overall detection rate of the custom panel, based on BRAF/NRAS/TERT promoter mutations, was 14/21 (67%) patient samples which included a TERT C250T mutation in one BRAF and NRAS mutation negative sample. A BRAF or NRAS mutation was detected in the ctDNA of 13/21 (62%) patients while TERT promoter mutations were detected in 10/21 (48%) patients. Co-occurrence of TERT promoter mutations with BRAF or NRAS mutations was found in 9/10 (90%) patients. The custom ctDNA panel showed a concordance of 16/21 (76%) with tissue based-detection and included 12 BRAF/NRAS mutation positive and 4 BRAF/NRAS mutation negative patients. The ctDNA mutation detection rate for stage IV was 12/16 (75%) and for stage III was 1/5 (20%). Based on BRAF, NRAS and TERT promoter mutations, the custom melanoma panel displayed a limit of detection of ~0.2% mutant allele frequency and showed significant correlation with droplet digital PCR. For one patient, a novel MAP2K1 H119Y mutation was detected in an NRAS/BRAF/TERT promoter mutation negative background. To increase the detection rate to >90% for stage IV melanoma patients, we plan to expand our custom panel to 50 genes. This study represents one of the first to successfully detect TERT promoter mutations in ctDNA from cutaneous melanoma patients using a targeted NGS panel.

Background: Immune checkpoint inhibitor (ICI) immunotherapies have revolutionized the treatment of melanoma, although drug resistance or concurrent immune-related adverse events (irAEs) still impact many patients. There is growing evidence that immunotherapy outcomes are influenced by the gut microbiome. This includes differential associations for key bacterial groups such as Bacteroidaceae and Ruminococacceae. However, how gut microbes interact with the immune system to influence the success of ICIs and/or the development of irAEs remains unclear. Methods: We longitudinally profiled the gut microbiome and circulating immune cell subsets in stage III melanoma patients from Australia and the Netherlands (n=126) treated on trial with combination anti-PD-1/anti-CTLA-4 immunotherapy in the neo-adjuvant setting (NCT02977052). Paired pre- and post-treatment (baseline/week 6) stool samples were analyzed using 16S rRNA gene sequencing (n=126) and matched PBMCs were comprehensively profiled using mass cytometry (n=71). Results: Treatment with anti-PD-1/anti-CTLA-4 immunotherapy was associated with an increase in the frequency (% total CD45+) of CD8+ effector memory T cells (Tem) (CD45RA- CCR7-) (P= 0.0096) and a reduction in regulatory T cells (Tregs) (CD25+FoxP3+) (P= 0.0029) between baseline and week 6. The reduction in Tregs was dominantly observed in responders (P= 0.0016) compared to non-responders (P= 0.9515). However, patients who developed severe irAEs were also particularly deficient in Tregs at week 6 compared to patients with no or mild toxicities (P= 0.0293). Notably, in patients where circulating Tregs were reduced, the degree of reduction in Tregs positively correlated with the baseline relative abundance of Bacteroides (P< 0.0001). Higher pre-treatment Bacteroides abundance was also linked to the development of more severe irAEs (P= 0.0472) and overall steroid use (P= 0.0345) prior to week 6. Thus, while Bacteriodes here is linked to a response-associated parameter (reduction in Tregs), it is also linked to severe, early irAEs. In contrast, a higher abundance of Ruminococcaceae was protective, and overall a greater proportion of patients with Ruminococcaceae dominated microbiomes were responders, highlighting a role for both bacterial groups in shaping ICI outcomes. Conclusions: While response to ICI therapy was associated with a decrease in circulating Tregs, excessive reduction in Tregs was observed in patients that develop severe irAEs. Together, this highlights the delicate balance between immune activation and regulation in facilitating anti-tumor immune responses whilst avoiding irAEs. Our data suggests that the gut microbiome may have a role in establishing immune tone prior to and during immunotherapy and may influence this “tipping point” and the risk of developing irAEs. Citation Format: Rebecca C. Simpson, Erin R. Shanahan, Marcel Batten, Ines P. Silva, Irene L. Reijers, Judith M. Versluis, Alexander M. Menzies, Maria Gonzalez, Umaimainthan Palendira, Andrew Holmes, James S. Wilmott, Christian U. Blank, Richard A. Scolyer, Georgina V. Long. Longitudinal microbiome-immune dynamics in melanoma patients treated with immune checkpoint inhibitor immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3463.

Purpose Patients with melanoma liver metastases have significantly reduced overall response and survival when treated with immune checkpoint inhibitors (ICI) compared to those without liver metastases. Melanoma liver metastases are less likely to respond to ICI compared to other sites of metastases, and the presence of liver metastases has also been associated with reduced responses to ICI at other metastatic sites. We aimed to profile circulating and tumor immune profiles of melanoma patients with versus without liver metastases to elucidate the factors behind this observation. Methods Pre-treatment PBMCs from 37 advanced melanoma patients (Cohort A) were profiled using mass cytometry (CyTOF) spanning 46 markers. Expression of specific immune cells were compared between those with (n = 8) vs without (n = 29) liver metastases. In a separate independent cohort of 93 untreated metastatic melanoma patients (Cohort B), FFPE tumour samples comprised of subcutaneous, lymph node (LN) and brain metastases were stained for myeloid and T cell markers using multiplex IHC. Immune cell populations in cohort B tissues were compared between patients with (n=40) vs without (n=53) liver metastases. Results PBMCs from patients in Cohort A with liver metastases had an increased proportion of a myeloid population characterised as HLA-DR+CD14+CD16- compared to patients without liver metastases (p = 0.035). However, a difference in CD68+CD14+CD16- myeloid cells was not seen in cohort B melanoma tissues (subcut, LN, brain metastases) between patients with vs without liver metastases. In subcutaneous tissues, there was a significantly reduced density of T cells in patients with liver metastases (median = 59 cells/mm2) compared to those without (median = 217 cells/mm2; p = 0.037). This trend was also observed in LN and brain metastases but did not reach significance. In brain metastases, a higher proportion of FoxP3+ T cells was observed in patients with liver metastases (p = 0.003). An increase in this population was also observed in the LN and subcutaneous metastases in the presence (vs absence) of liver metastases, however this did not reach significance. LN metastases also showed a reduced proportion of both TIM3+ (p = 0.049) and CD103+ (p = 0.048) T cells in patients with liver metastases (vs absence), and a similar trend was observed in subcutaneous metastases. In contrast, brain metastases showed the opposite trend as well as higher proportion of PD1+ T cells in patients with liver metastases vs those without (p = 0.033). Conclusion These data provide insights into the differences in the anti-tumor immune profiles of patients with versus without liver metastases; the presence of liver metastases may have a specific impact at different metastatic sites. This highlights the need for further validation and investigation into the mechanism by which the presence of liver metastases may exert this effect. Citation Format: Jordan W. Conway, Felix Marsh-Wakefield, Kazi J. Nahar, Serigne N. Lo, Ismael A. Vergara, Tuba N. Gide, Grace H. Attrill, Jorja Braden, Matteo S. Carlino, Robyn P. Saw, John F. Thompson, Andrew J. Spillane, Kerwin F. Shannon, Brindha Shivalingam, Alexander M. Menzies, Umaimainthan Palendira, James S. Wilmott, Georgina V. Long, Richard A. Scolyer, Ines Pires Da Silva. The association between melanoma liver metastases (mets) and the systemic anti-tumor immune profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 81.

Background: While immune checkpoint inhibitors (ICI) have become the standard-of-care for advanced melanoma patients, only half of treated patients will survive beyond 5-years and many develop significant toxicity. The PIP study is combining pre-treatment clinical, molecular, and immunological profiles of melanoma patients to provide accurate prediction of response to ICI therapies. Methods: 504 patients with advanced melanoma who received anti-PD-1±CTLA-4 ICI were studied to develop predictive models of resistance to ICI. Resistance was defined as patients with progressive disease as best response, or partial response/stable disease with Results: Models were developed and validated using sequential addition of omics features to relevant clinical factors. Baseline clinical data alone achieved an AUC of 68%. Clinical plus three-tier TMB (20 mut/mb) achieved an AUC of 78%. Clinical data plus GEP achieved 79% AUC, inclusive of tumor inflammation, antigen presentation and T-cell related signatures. Clinical and MIF spatial pathology achieved an 82% AUC including the distances between T-cells, CD16+ cells and melanoma cells as features in the model. Finally, the combination of TMB and GEP achieved an 83% AUC. Prospective validation of the models is awaiting follow-up milestones. Conclusion: Multi-omic models using pre-treatment tissue and clinicopathology can significantly improve the accuracy of predicting patient outcomes to ICI treatments compared to baseline clinical data alone. Several models may be required based on different omic combinations to account for the reality of biopsy suitability and assay failures. These findings prove personalized precision treatment of patients with immunotherapies is possible in the clinical setting and such approaches should become routine care. Citation Format: Tuba N. Gide, Nurudeen A. Adegoke, Yizhe Mao, Monica Lennox, Saurab Raj, Camelia Quek, Ismael A. Vergara, Nigel Maher, Alison Potter, Robyn P. Saw, John F. Thompson, Andrew J. Spillane, Kerwin F. Shannon, Matteo S. Carlino, Maria Gonzalez, Serigne N. Lo, Alexander M. Menzies, Inês Pires da Silva, Richard A. Scolyer, Georgina V. Long, James S. Wilmott. Predictive biomarker models of immunotherapy response in patients with metastatic melanoma: genomic, transcriptomic, and immune profiles from the Personalised Immunotherapy Program (PIP). [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5701.

Background: Different metastatic sites have distinct response rates to immune checkpoint inhibitors (ICI), suggesting that anatomical locations play a role in treatment response and survival. This project investigated the impact that sites of metastases present at baseline - ie. before starting treatment - have on the anatomical patterns of progression and their association with survival in patients (pts) exposed to ICI and BRAF/MEK inhibitors (BRAF/MEKi) as first line treatment. Methods: We curated the progression history of distant metastases of 568 stage IV pts; 352 pts had first line treatment with antiPD1 +/- antiCTLA4, and 216 pts had first line BRAF/MEKi. We sought to investigate the association between sites of metastases at baseline and (a) sites of progression in pts who failed first line anti-PD1 vs first line BRAF/MEKi, (b) sites of progression in pts who failed first line anti-PD1 with innate vs acquired resistance, and (c) survival of all pts, from time of first line treatment to last follow-up. Results: Using a sophisticated mathematical graph representation of anatomical disease progression, we unveiled sites of metastases at baseline that impacted where new sites of metastases developed on treatment failure. In pts with brain metastasis at baseline, pts who failed anti-PD1 had higher progression in the brain compared to BRAF/MEKi progressors (68.1% in anti-PD1 progressors vs 62.5% in BRAF/MEKi progressors). In contrast, the opposite trend was observed in the progression to the brain in pts with no brain metastasis at baseline, which was lower in anti-PD1 progressors compared to BRAF/MEKi progressors (20.6% in anti-PD1 progressors vs 32.6% in BRAF/MEKi progressors).Within pts who failed anti-PD1, pts with innate resistance (n=95) had a higher rate of progression in the brain (42.1%) compared to pts with acquired (n=36) resistance (25%). Among pts with innate resistance who had brain metastasis at baseline (n=36), 80.6% progressed in the brain. In contrast, among pts with innate resistance without brain metastasis at baseline (n=59), only 18.6% progressed to the brain.Sites of metastases at baseline also had an impact on the survival of pts. In BRAF/MEKi pts, brain metastasis at baseline was not associated with survival (log-rank p-value=0.6). In contrast, anti-PD1 pts with brain metastasis at baseline had worst survival (2-yr survival 56%) compared to pts without brain metastasis at baseline (2-yr survival 73%, log-rank p-value=0.005). Utilisation of this graph representation for the development of a time-dependent predictor of brain metastases will be presented. Further associations of metastatic sites of disease at baseline with progression and survival will be discussed. Conclusions: Different sites of metastases at baseline have a distinct effect on the progression patterns and survival of pts who received BRAF/MEKi or anti-PD1 as first line treatment. Citation Format: Ismael A. Vergara, Serigne N. Lo, Isabel Li, Alexander M. Menzies, Matteo S. Carlino, Richard A. Scolyer, Georgina V. Long, Ines Pires da Silva. Sites of metastases prior to systemic treatment influence progression patterns and survival in stage IV melanoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6747.

PURPOSE: Neoadjuvant immunotherapy may improve the clinical outcome of regionally advanced operable melanoma and allows for rapid clinical and pathologic assessment of response. We examined neoadjuvant pembrolizumab and high dose interferon alfa-2b (HDI) therapy in patients with resectable advanced melanoma. PATIENTS AND METHODS: Patients with resectable stage III/IV melanoma were treated with concurrent pembrolizumab 200 mg intravenously (IV) every 3 weeks and HDI 20 MU/m(2)/day IV, 5 days/week for 4 weeks, then 10 MU/m(2)/day subcutaneously 3 days/week for 2 weeks. Definitive surgery followed, and adjuvant combination immunotherapy completing a year of treatment. Primary endpoint was safety of the combination. Secondary endpoints included overall response rate (ORR), pathologic complete response (pCR), recurrence-free survival (RFS), and overall survival (OS). Blood samples for correlative studies were collected throughout. Tumor tissue was assessed by immunohistochemistry (IHC) and flow cytometry at baseline and at surgery. RESULTS: 31 patients were enrolled, and 30 were evaluable. At data cutoff (October 2, 2019), median follow-up for OS was 37.87 months (range; 33.2–43.47). Median OS and RFS were not reached. Radiographic ORR was 73.3% (95% CI: 55.5%−85.8%), with a 43% (95% CI: 27.3%−60.1%) pathologic complete response (pCR) rate. None of the patients with a pCR have recurred. HDI and pembrolizumab were discontinued in 73% and 43% of patients, respectively. Correlative analyses suggested that intratumoral PD-1/PD-L1 interaction and HLA-DR expression are associated with pCR (p=0.002 and p=0.008, respectively). CONCLUSIONS: Neoadjuvant concurrent HDI and pembrolizumab demonstrated promising clinical activity despite high rates of treatment discontinuation. pCR is a prognostic indicator.

9575 Background: Both anti-PD-1 antibodies and BRAK/MEK inhibitors (BRAF/MEKi) reduce the risk of recurrence for patients with resected stage III melanoma. For patients with V600 BRAF-mutated melanoma who recur with resectable disease on or after adjuvant, many may be suitable for ‘second adjuvant' treatment after surgery. We sought to examine the efficacy and safety of ‘second adjuvant’ BRAF/MEKi in patients who recurred despite adjuvant PD-1 based immunotherapy. Methods: Patients with V600 BRAF-mutated melanoma treated with adjuvant PD-1 based immunotherapy for resected stage III/IV disease who recurred, underwent resection of recurrence and were then treated with adjuvant BRAF/MEKi were identified retrospectively from 13 centres. Demographics, disease characteristics, treatment details, and outcome data were examined. Results: 55 patients were included; median age at commencement of PD-1 was 53y, most were V600E (91%) and had IIIB (42%) or IIIC (44%) melanoma. PD-1 based adjuvant therapy included nivolumab (71%), nivolumab plus ipilimumab (14%), pembrolizumab (13%) and pembrolizumab plus mRNA-4157 vaccine (2%). Patients had initial recurrence after mean 8.4 months (95% CI 7.4-10.6), mainly while on treatment (65%), in regional nodes (42%), in-transit metastases (ITMs; 38%), both regional nodes and ITMs (7%) and distant metastases (13%). Surgical management included CLND (36%), selected nodal resection (11%), ITM resection (33%) and resection of distant metastasis (13%). A minority had adjuvant radiotherapy (17%). Stage at start of second adjuvant BRAF/MEKi included IIIB (29%), IIIC (53%) IIID (4%) and IV (15%). Patients received dabrafenib and trametinib (95%, N = 52) and encorafenib and binimetinib (5%, N = 3). After a median follow up of 21.4 months (19.7-25.4), 17 (31%) patients have recurred again. Mean duration of treatment was 9 months (95% CI 7.4-10.6); 20% ceased for toxicity, 7% for recurrence and 35% were on treatment at last follow up. The most common toxicity was pyrexia (43%) and 21% patients experienced a severe (G3-4) adverse event. Median RFS was 33.4 months (14.3.7-NR) and median DMFS was not reached. At 12 months, 72% (59-88) of patients were recurrence free and 90% (81-100) were free of distant recurrence. For those whose disease recurred again, most recurred after cessation of second adjuvant BRAF/MEKi (13/17, 76%). 7 (41%) recurred locally and 8 (47%) recurred with new metastatic disease but none had brain metastases. Conclusions: This is the first study examining outcomes of patients receiving second adjuvant targeted therapy for melanoma, after failure of adjuvant PD-1 based immunotherapy. While RFS appears shorter compared to first line trials, second adjuvant treatment with BRAF/MEKi appears safe and active in preventing further recurrence. Further data on sequencing adjuvant therapies are needed.

Sarcoidosis is a non‐infective granulomatous disorder of unknown aetiology, with cutaneous involvement affecting up to 30% of patients. Drug‐induced sarcoidosis has been reported secondary to modern melanoma therapies including immune‐checkpoint inhibitors and first generation BRAF inhibitors such as vemurafenib and dabrafenib. Herein, we report a case of cutaneous micropapular sarcoidosis that first developed on immune‐checkpoint inhibition with ipilimumab and nivolumab for metastatic melanoma, which was exacerbated and further complicated by pityriasis rubra pilaris‐like palmar plaques upon transition to a next‐generation BRAF‐dimerisation inhibitor. Both the micropapular eruption and palmar plaques rapidly resolved after cessation of the novel BRAF‐inhibitor and concurrent commencement of hydroxychloroquine. It is unclear how inhibition of BRAF‐dimerisation results in granuloma formation, though upregulation of TH1/TH17 T‐cells and impairment of T‐reg cells may be responsible. Clinicians should be aware of the potential for exacerbation of sarcoidosis when transitioning from immune‐checkpoint inhibitors to these novel BRAF‐dimerisation inhibitors, particularly as their uptake in treating cancers increases beyond clinical trials. Further studies are required to assess whether these next‐generation agents can trigger sarcoidosis de‐novo, or simply exacerbate pre‐existing sarcoidosis.

COMBI-AD demonstrated long-term benefit of adjuvant dabrafenib plus trametinib in patients with resected stage III BRAF V600E/K-mutant melanoma; however, 9% of patients permanently discontinued therapy due to pyrexia. COMBI-APlus evaluated whether an adapted pyrexia management algorithm reduces high-grade pyrexia and pyrexia-related adverse outcomes.COMBI-APlus is an open-label, phase IIIb trial evaluating an adapted pyrexia management algorithm in patients with high-risk resected stage III BRAF V600E/K-mutant melanoma treated with up to 12 months of adjuvant dabrafenib plus trametinib. Both drugs were interrupted for pyrexia (temperature ≥38°C) or the occurrence of pyrexia syndrome for suspected recurrent pyrexia. Treatment was restarted at the same dose once patients were symptom free for ≥24 h. The primary endpoint was the composite rate of grade 3/4 pyrexia, hospitalisation due to pyrexia, or permanent discontinuation due to pyrexia versus historical COMBI-AD control (20.0%; 95% confidence interval [CI], 16.3%-24.1%).At data cutoff (5 October 2020), COMBI-APlus met its primary endpoint of significant improvement in the composite rate of pyrexia (8.0% [95% CI, 5.9%-10.6%]), with rates of 3.8% for grade 3/4 pyrexia, 4.3% for hospitalisation due to pyrexia, and 2.4% for discontinuation due to pyrexia. Estimated 12-month relapse-free survival was 91.8% (95% CI, 89.0%-93.9%). The most common adverse events were consistent with those in COMBI-AD, and 14.7% of patients permanently discontinued treatment due to adverse events.The adapted pyrexia management algorithm appears to reduce the incidence of severe pyrexia outcomes, enables patients to manage pyrexia at home, and helps patients remain on treatment.NCT03551626.

Background Adjuvant immunotherapy is revolutionising care for patients with resected stage III and IV melanoma. However, immunotherapy may be associated with toxicity, making treatment decisions complicated. This study aimed to identify factors physicians and nurses considered regarding adjuvant immunotherapy for melanoma. Methods In-depth interviews were conducted with physicians (medical oncologists, surgeons and dermatologists) and nurses managing patients with resected stage III melanoma at three Australian tertiary melanoma centres between July 2019 and March 2020. Factors considered regarding adjuvant immunotherapy were explored. Recruitment continued until data saturation and thematic analysis was undertaken. Results Twenty-five physicians and nurses, aged 28–68 years, 60% females, including eleven (44%) medical oncologists, eight (32%) surgeons, five (20%) nurses, and one (4%) dermatologist were interviewed. Over half the sample managed five or more new resected stage III patients per month who could be eligible for adjuvant immunotherapy. Three themes about adjuvant immunotherapy recommendations emerged: [1] clinical and patient factors, [2] treatment information provision, and [3] individual physician/nurse factors. Melanoma sub-stage and an individual patient’s therapy risk/benefit profile were primary considerations. Secondary factors included uncertainty about adjuvant immunotherapy’s effectiveness and their views about treatment burden patients might consider acceptable. Conclusions Patients’ disease sub-stage and their treatment risk versus benefit drove the melanoma health care professionals’ adjuvant immunotherapy endorsement. Findings clarify clinician preferences and values, aiding clinical communication with patients and facilitating clinical decision-making about management options for resected stage III melanoma.

Despite remarkably improved outcomes with immune checkpoint inhibition, many patients with metastatic melanoma will eventually require further therapy. Chemotherapy has limited activity when used first-line but can alter the tumour microenvironment and does improve efficacy when used in combination with immunotherapy in lung cancer. Whether chemotherapy after checkpoint inhibitor failure has relevant activity in patients with metastatic melanoma is unknown.Patients with metastatic melanoma treated with chemotherapy after progression on immunotherapy with checkpoint inhibitors were identified retrospectively from 24 melanoma centres. Objective response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety were examined.In total, 463 patients were treated between 2007 and 2017. Fifty-six per cent had received PD-1-based therapy before chemotherapy. Chemotherapy regimens included carboplatin + paclitaxel (32%), dacarbazine (25%), temozolomide (15%), taxanes (9%, nab-paclitaxel 4%), fotemustine (6%) and others (13%). Median duration of therapy was 7.9 weeks (0-108). Responses included 0.4% complete response (CR), 12% partial response (PR), 21% stable disease (SD) and 67% progressive disease (PD). Median PFS was 2.6 months (2.2, 3.0), and median PFS in responders was 8.7 months (6.3, 16.3), respectively. Twelve-month PFS was 12% (95% CI 2-15%). In patients who had received anti-PD-1 before chemotherapy, the ORR was 11%, and median PFS was 2.5 months (2.1, 2.8). The highest activity was achieved with single-agent taxanes (N = 40), with ORR 25% and median PFS 3.9 months (2.1, 6.2). Median OS from chemotherapy start was 7.1 months (6.5, 8.0). Subsequent treatment with checkpoint inhibitors achieved a response rate of 16% with a median PFS of 19.1 months (2.0-43.1 months). No unexpected toxicities were observed.Chemotherapy has a low response rate and short PFS in patients with metastatic melanoma who have failed checkpoint inhibitor therapy, although activity varied between regimens. Chemotherapy has a limited role in the management of metastatic melanoma.

BACKGROUND Patients with metastatic melanoma have variable responses to combination ipilimumab and nivolumab. The objectives of this study were to examine the patterns of response and survival in patients treated with combination ipilimumab and anti-PD-1 therapy (IPI + PD1) and to explore the nature of pseudoprogression and acquired resistance. METHODS Patients with metastatic melanoma who received treatment with first-line IPI + PD1 had all metastases ≥5 mm measured on computed tomography/magnetic resonance imaging studies. The lesional response rate (LRR) and the overall response rate (ORR) were determined according to Response Evaluation Criteria in Solid Tumors, version 1.1. RESULTS In total, 140 patients who had 833 metastases were studied. The ORR and the overall complete response (CR) rate decreased as tumor burden or the number of metastases increased. Metastases that had a CR (49%) were smaller than metastases without a CR (median, 13 vs 17 mm; P

Checkpoint inhibitors produce durable responses in numerous metastatic cancers, but immune-related adverse events (irAEs) complicate and limit their benefit. IrAEs can affect organ systems idiosyncratically; presentations range from mild and self-limited to fulminant and fatal. The molecular mechanisms underlying irAEs are poorly understood. Here, we report a fatal case of encephalitis arising during anti-programmed cell death receptor 1 therapy in a patient with metastatic melanoma. Histologic analyses revealed robust T cell infiltration and prominent programmed death ligand 1 expression. We identified 209 reported cases in global pharmacovigilance databases (across multiple cancer types) of encephalitis associated with checkpoint inhibitor regimens, with a 19% fatality rate. We performed further analyses from the index case and two additional cases to shed light on this recurrent and fulminant irAE. Spatial and multi-omic analyses pinpointed activated memory CD4+ T cells as highly enriched in the inflamed, affected region. We identified a highly oligoclonal T cell receptor repertoire, which we localized to activated memory cytotoxic (CD45RO+GZMB+Ki67+) CD4 cells. We also identified Epstein-Barr virus-specific T cell receptors and EBV+ lymphocytes in the affected region, which we speculate contributed to neural inflammation in the index case. Collectively, the three cases studied here identify CD4+ and CD8+ T cells as culprits of checkpoint inhibitor-associated immune encephalitis.

Purpose: Immunotherapies targeting costimulating and coinhibitory checkpoint receptors beyond PD-1 and CTLA-4 have entered clinical trials. Little is known about the relative abundance, coexpression, and immune cells enriched for each specific drug target, limiting understanding of the biological basis of potential treatment outcomes and development of predictive biomarkers for personalized immunotherapy. We sought to assess the abundance of checkpoint receptors during melanoma disease progression and identify immune cells enriched for them. Experimental Design: Multiplex immunofluorescence staining for immune checkpoint receptors (ICOS, GITR, OX40, PD-1, TIM-3, VISTA) was performed on 96 melanoma biopsies from 41 treatment-naïve patients, including patient-matched primary tumors, nodal metastases, and distant metastases. Mass cytometry was conducted on tumor dissociates from 18 treatment-naïve melanoma metastases to explore immune subsets enriched for checkpoint receptors. Results: A small subset of tumor-infiltrating leukocytes expressed checkpoint receptors at any stage of melanoma disease. GITR and OX40 were the least abundant checkpoint receptors, with 70%) and other coinhibitory but not costimulatory receptors. The proportion of GITR+ T cells decreased from primary melanoma (>5%) to lymph node ( Conclusions: This study provides the first comprehensive assessment of immune checkpoint receptor expression in any cancer and provides important data for rational selection of targets for trials and predictive biomarker development.

Purpose: Combination PD-1 and CTLA-4 inhibitor therapy has dramatically improved the survival of patients with advanced melanoma but is also associated with significant immune-related toxicities. This study sought to identify circulating cytokine biomarkers of treatment response and immune-related toxicity. Experimental Design: The expression of 65 cytokines was profiled longitudinally in 98 patients with melanoma treated with PD-1 inhibitors, alone or in combination with anti-CTLA-4, and in an independent validation cohort of 49 patients treated with combination anti-PD-1 and anti-CTLA-4. Cytokine expression was correlated with RECIST response and immune-related toxicity, defined as toxicity that warranted permanent discontinuation of treatment and administration of high-dose steroids. Results: Eleven cytokines were significantly upregulated in patients with severe immune-related toxicities at baseline (PRE) and early during treatment (EDT). The expression of these 11 cytokines was integrated into a single toxicity score, the CYTOX (cytokine toxicity) score, and the predictive utility of this score was confirmed in the discovery and validation cohorts. The AUC for the CYTOX score in the validation cohort was 0.68 at PRE [95% confidence interval (CI), 0.51–0.84; P = 0.037] and 0.70 at EDT (95% CI, 0.55–0.85; P = 0.017) using ROC analysis. Conclusions: The CYTOX score is predictive of severe immune-related toxicity in patients with melanoma treated with combination anti-CTLA-4 and anti-PD-1 immunotherapy. This score, which includes proinflammatory cytokines such as IL1a, IL2, and IFNα2, may help in the early management of severe, potentially life-threatening immune-related toxicity. See related commentary by Johnson and Balko, p. 1452

Purpose: BRAF V600E and V600K melanomas have distinct clinicopathologic features, and V600K appear to be less responsive to BRAFi±MEKi. We investigated mechanisms for this and explored whether genotype affects response to immunotherapy. Experimental Design: Pretreatment formalin-fixed paraffin-embedded tumors from patients treated with BRAFi±MEKi underwent gene expression profiling and DNA sequencing. Molecular results were validated using The Cancer Genome Atlas (TCGA) data. An independent cohort of V600E/K patients treated with anti–PD-1 immunotherapy was examined. Results: Baseline tissue and clinical outcome with BRAFi±MEKi were studied in 93 patients (78 V600E, 15 V600K). V600K patients had numerically less tumor regression (median, −31% vs. −52%, P = 0.154) and shorter progression-free survival (PFS; median, 5.7 vs. 7.1 months, P = 0.15) compared with V600E. V600K melanomas had lower expression of the ERK pathway feedback regulator dual-specificity phosphatase 6, confirmed with TCGA data (116 V600E, 17 V600K). Pathway analysis showed V600K had lower expression of ERK and higher expression of PI3K-AKT genes than V600E. Higher mutational load was observed in V600K, with a higher proportion of mutations in PIK3R1 and tumor-suppressor genes. In patients treated with anti–PD-1, V600K (n = 19) had superior outcomes than V600E (n = 84), including response rate (53% vs. 29%, P = 0.059), PFS (median, 19 vs. 2.7 months, P = 0.049), and overall survival (20.4 vs. 11.7 months, P = 0.081). Conclusions: BRAF V600K melanomas appear to benefit less from BRAFi±MEKi than V600E, potentially due to less reliance on ERK pathway activation and greater use of alternative pathways. In contrast, these melanomas have higher mutational load and respond better to immunotherapy.

Simple Summary Immune checkpoint therapies have significantly improved the survival of patients with metastatic melanoma, however approximately 50% of patients exhibit no response. Understanding the underlying clinical, pathologic and genetic factors associated with failed response to immunotherapies is key to identifying therapeutic strategies to overcome resistance. Here, we investigated the baseline tumour characteristics of patients with innate resistance to anti-PD-1-based immunotherapies. This study is the first on non-responders to integrate detailed clinical and molecular analyses and has identified two distinct clusters of patients with clinically relevant key targetable proteins. Abstract While immune checkpoint inhibitors targeting the CTLA-4 and PD-1 receptors have significantly improved outcomes of many patients with metastatic melanoma, there remains a group of patients who demonstrate no benefit. In this study, we sought to characterise patients who do not respond to anti-PD-1-based therapies based on their clinical, genetic and immune profiles. Forty patients with metastatic melanoma who did not respond to anti-PD-1 +/− anti-CTLA-4 treatment were identified. Targeted RNA sequencing (n = 37) was performed on pretreatment formalin-fixed paraffin-embedded (FFPE) melanoma specimens. Patients clustered into two groups based on the expression profiles of 26 differentially expressed genes: an immune gene rich group (n = 17) expressing genes associated with immune and T cell signalling, and a second group (n = 20) expressing genes associated with metabolism, signal transduction and neuronal signalling. Multiplex immunohistochemistry validated significantly higher densities of tumour-infiltrating lymphocytes (TILs) and macrophages in the immune gene-rich group. This TIL-high subset of patients also demonstrated higher expression of alternative immune-regulatory drug targets compared to the TIL-low group. Patients were also subdivided into rapid progressors and other progressors (cut-off 2 mo progression-free survival), with significantly lower TILs (p = 0.04) and CD68+ macrophages (p = 0.0091) in the rapid progressors. Furthermore, a trend towards a higher tumour burden was observed in rapid progressors (p = 0.06). These data highlight the need for a personalised and multilayer (clinical and molecular) approach for identifying the most appropriate treatments for anti-PD-1 resistant patients and provides insight into how individual treatment strategies can be achieved.

Purpose: Programmed cell death receptor-1 (PD-1) inhibitors are frontline therapy in advanced melanoma. Severe immune-related adverse effects (irAEs) often require immunosuppressive treatment with glucocorticoids (GCCs), but GCC use and its correlation with patient survival outcomes during anti–PD-1 monotherapy remains unclear. Experimental Design: In this multicenter retrospective analysis, patients treated with anti–PD-1 monotherapy between 2009 and 2019 and detailed GCC use, data were identified from five independent cohorts, with median follow-up time of 206 weeks. IrAEs were tracked from the initiation of anti–PD-1 until disease progression, initiation of a new therapy, or last follow-up. Correlations between irAEs, GCC use, and survival outcomes were analyzed. Results: Of the entire cohort of 947 patients, 509 (54%) developed irAEs. In the MGH cohort [irAE(+) n = 90], early-onset irAE (within 8 weeks of anti–PD-1 initiation) with high-dose GCC use (≥60-mg prednisone equivalent once a day) was independently associated with poorer post-irAE PFS/OS (progression-free survival/overall survival) [post-irAE PFS: HR, 5.37; 95% confidence interval (CI), 2.10–13.70; P < 0.001; post-irAE OS: HR, 5.95; 95% CI, 2.20–16.09; P < 0.001] compared with irAEs without early high-dose GCC use. These findings were validated in the combined validation cohort [irAE(+) n = 419, post-irAE PFS: HR, 1.69; 95% CI, 1.04–2.76; P = 0.04; post-irAE OS: HR, 1.97; 95% CI, 1.15–3.39; P = 0.01]. Similar findings were also observed in the 26-week landmark analysis for post–irAE-PFS but not for post–irAE-OS. A sensitivity analysis using accumulated GCC exposure as the measurement achieved similar results. Conclusions: Early high-dose GCC use was associated with poorer PFS and OS after irAE onset. Judicious use of GCC early during anti–PD-1 monotherapy should be considered. Further prospective randomized control clinical trials designed to explore alternative irAE management options are warranted.

Although previously the mainstay of treatment, the role of surgery in the management of patients with oligometastatic stage IV melanoma has changed with the advent of effective systemic therapies (most notably immunotherapy). Contemporary treatment options for patients with asymptomatic solitary or oligo-metastases include upfront surgery followed by adjuvant immunotherapy or upfront immunotherapy with salvage surgery as required. For suspected solitary or oligo-metastases, surgery serves both diagnostic and therapeutic purposes. Advances in radiological technology allow metastases to be detected earlier and surgery to be less morbid. Surgical morbidities are generally more tolerable than serious immune-related adverse effects, but surgery may be less effective. Upfront immunotherapy ensures that futile surgery is not offered for rapidly progressive disease. It also provides an opportunity to assess response to treatment, which predicts outcome, and may obviate the need for surgery. However, it is important not to miss a window of opportunity for surgical intervention, whereby if disease progresses on immunotherapy it becomes unresectable. In situations where local therapy is recommended but surgery is not desired, stereotactic radiosurgery may be an effective alternative. The decision-making process regarding upfront surgery versus immunotherapy needs to take place within a specialist melanoma multidisciplinary setting and be customised to individual patient and tumour factors. Ultimately, high-level clinical trial evidence is required to resolve uncertainties in the management of patients with oligometastatic stage IV melanoma but the complexity of the varying presentations may make trial design challenging.

Background: Safe, effective treatment options for advanced melanoma that progressed on a PD-1/PD-L1 inhibitor is an unmet medical need. Results of the phase 1b KEYNOTE-029 trial showed promising antitumor activity in advanced melanoma with pembro combined with a CTLA-4 inhibitor. This ongoing, open-label, multiarm phase 1/2 study (NCT03179436) evaluating the CTLA-4 inhibitor Qmab + pembro showed antitumor activity as first-line treatment for advanced NSCLC and for previously treated extensive-stage SCLC. Data from the efficacy expansion phase in pts with advanced melanoma that progressed on a PD-1/PD-L1 inhibitor are presented. Methods: Pts with unresectable stage III-IV melanoma and confirmed progressive disease (PD) per iRECIST within 12 wk of the last dose of a PD-1/PD-L1 inhibitor given alone or in combination for ≥2 doses (combinations with CTLA-4 inhibitors were not allowed) were randomly assigned (1:1) to receive Qmab 25 mg IV Q6W with or without pembro 400 mg IV Q6W; 100 pts in the Qmab + pembro arm and 40 pts in the Qmab monotherapy arm were planned for enrollment. Treatment in both arms was given for up to 18 cycles (~2 y) or until PD, toxicity, or pt withdrawal. Pts who had PD after ≥2 Qmab monotherapy cycles could crossover to Qmab + pembro. Tumor imaging was assessed Q9W to wk 54 and Q12W thereafter. Primary end points were safety and ORR by BICR per RECIST v1.1. Secondary and exploratory end points included DOR and PFS by BICR per RECIST v1.1 and OS. Results: 151 pts were enrolled (n = 111, Qmab + pembro; n = 40, Qmab monotherapy); median time from first dose to database cutoff was 7.7 mo. In all pts, median age was 64 y; 66% of pts were male, 33% had BRAF-mutant tumors, and 50% had elevated LDH. Treatment-related adverse events (TRAEs) were reported in 87 pts (78%) in the Qmab + pembro arm and 24 pts (60%) in the Qmab monotherapy arm; grade 3/4 TRAEs were reported in 16 pts (14%) and 3 pts (8%), respectively. The most common TRAEs were pruritus (26%), fatigue (14%), diarrhea (14%), and rash (13%). No treatment-related deaths occurred in either arm; 5% of pts discontinued because of TRAEs. Confirmed ORR was 9% (95% CI, 4.4-15.9) with Qmab + pembro (1 CR, 9 PRs) and 3% (95% CI, 0.1-13.2) with Qmab monotherapy (1 PR). Median DOR was not reached (NR; range, 2.0+ to 13.8+ mo) with Qmab + pembro. DOR was 1.9+ with Qmab monotherapy. Median PFS was 2.1 mo (95% CI, 2.1-3.2) with Qmab + pembro and 2.1 mo (95% CI, 2.1-2.5) with Qmab monotherapy; 6-mo PFS rates were 21% and 13%, respectively. Median OS was NR (95% CI, 11.2 mo to NR) with Qmab + pembro and 7.8 mo (95% CI, 6.3 to NR) with Qmab monotherapy; 6-mo OS rates were 74% and 73%, respectively. Conclusions: Qmab + pembro was generally well tolerated and provided modest antitumor activity in pts with advanced melanoma that progressed on a PD-1/PD-L1 inhibitor. This combination and a coformulation of Qmab + pembro will be further investigated in the KEYMAKER-U02 study. Citation Format: Sanjeev Deva, Jacek Mackiewicz, Stephane Dalle, Helen Gogas, Iwona Lugowska, Alfonso Berrocal, Alexander M. Menzies, Michele Maio, Adnan Nagrial, Karmele Mujika Eizmendi, Jean-Jacques Grob, Christian Caglevic, Megan Lyle, Juan Martin-Liberal, Rachel Altura, Yixin Ren, Anuradha Khilnani, Jobin Cyrus, Shabana Siddiqi, Michal Lotem. Phase 1/2 study of quavonlimab (Qmab) + pembrolizumab (pembro) in patients (pts) with advanced melanoma that progressed on a PD-1/PD-L1 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT557.

9558 Background: Adjuvant immunotherapy has revolutionized the management of resectable melanoma, substantially reducing the risk of recurrence but at the risk of immune-related adverse events (AE). This study aimed to quantify patients' preferences for adjuvant immunotherapy, the influence of varying levels of key attributes, and baseline characteristics associated with preferences. Methods: We performed a discrete choice experiment (DCE), including patients with resected stage III melanoma considering or having received adjuvant immunotherapy. Patients chose between twelve randomly presented choice tasks of two alternative options (adjuvant immunotherapy versus observation without adjuvant immunotherapy). The two options varied across two-three levels of six attributes: chance of 3-year melanoma recurrence, mild, permanent, or fatal AE, drug regimen, and out-of-pocket costs. We calculated the marginal rate of substitution (MRS, how much an individual was willing to trade one attribute for preferred levels of another) and willingness-to-pay (WTP, maximum price to trade their preferred attributes) per year. Results: One hundred and sixteen patients completed the DCE. Patients chose adjuvant immunotherapy over observation without adjuvant immunotherapy in 70% of choice tasks. Patients preferred adjuvant immunotherapy with reduced probabilities of recurrence (OR 0.76, 95% CI 0.70-0.83, p

TPS9599 Background: Anti-PD1-based immunotherapies have been approved for many cancer types and are now a standard therapy for advanced melanoma. Despite this, ̃50% of advanced melanoma patients (pts) fail to respond or eventually progress after response. It is therefore critical to identify pts with a low likelihood of response to anti-PD1-based therapy and efficiently assess activity of rationally-selected alternative novel immunotherapies. Methods: We designed this investigator-initiated phase II PIP-Trial to evaluate two consecutive biomarker testing platforms, followed by the activity of rationally selected 5 novel agents in pts with advanced melanoma. Two separate pt populations are included: Part-A) treatment-naïve pts predicted to be resistant to either anti-PD-1 alone or combined with ipilimumab using Biomarker Test-1); and Part-B) pts who had progressed on 1 prior line of PD1-based therapy. Part-A) is a Bayesian adaptive multi-arm multi-stage design using response adaptive randomisation after a burn-in period where pts are randomised to the existing arms with equal probability. From then on, regular interim analyses will be carried out with the objective to either drop poorly performing arms or continue. Part-B) is an open platform without control that combined a selection and an expansion phase to identify best novel agent(s) as second-line therapy. Expansion phase decisions will be based on enrichment for biomarker Test-2. Dropping an arm occurs when the posterior probability of observing a clinically significant effect on the primary outcome (i.e. 6-month RECIST objective response rate (ORR)) is low. The operational characteristics of the design were investigated through simulations considering 4 plausible scenarios with 40% ORR in the control arm (anti-PD1 + Anti-CTLA4). Simulations were based on the upcoming R package BATS. Part-A has at least 85% power to detect a 30% absolute improvement in ORR with respect to the control arm (with a max N = 216 – Table below). Part-B will be able to select two promising treatments in the expansion phase and formally test their efficacy against a minimum ORR of 25% at 80% power (max N = 150). [Table: see text]

BackgroundAdjuvant immune checkpoint inhibitor (ICI) immunotherapies have significantly reduced the recurrence rate in high-risk patients with stage III melanoma compared with surgery alone. However, 48% of anti-PD-1-treated patients will develop recurrent disease within 4 years. There is a need to identify biomarkers of recurrence after adjuvant ICI to enable identification of patients in need of alternative treatment strategies. As cytotoxic T cells are critical for the antitumor response to anti-PD-1, we sought to determine whether specific subsets were predictive of recurrence in anti-PD-1-treated high-risk patients with stage III melanoma.MethodsAssociations with recurrence in patients with stage III melanoma were sought by analyzing resection specimens (n=103) taken prior to adjuvant nivolumab/pembrolizumab±low-dose/low-interval ipilimumab. Multiplex immunohistochemistry was used to quantify intratumoral CD8+ T-cell populations using phenotypical markers CD39, CD103, and PD-1.ResultsWith a median follow-up of 19.3 months, 37/103 (36%) of patients had a recurrence. Two CD8+ T-cell subpopulations were significantly associated with recurrence. First, CD39+ tumor-resident memory cells (CD39+CD103+PD-1+CD8+ (CD39+ Trm)) comprised a significantly higher proportion of CD8+ T cells in recurrence-free patients (p=0.0004). Conversely, bystander T cells (CD39−CD103−PD-1−CD8+) comprised a significantly greater proportion of T cells in patients who developed recurrence (p=0.0002). Spatial analysis identified that CD39+ Trms localized significantly closer to melanoma cells than bystander T cells. Multivariable analysis confirmed significantly improved recurrence-free survival (RFS) in patients with a high proportion of intratumoral CD39+ Trms (1-year RFS high 78.1% vs low 49.9%, HR 0.32, 95% CI 0.15 to 0.69), no complete lymph node dissection performed, and less advanced disease stage (HR 2.85, 95% CI 1.13 to 7.19, and HR 1.29, 95% CI 0.59 to 2.82). The final Cox regression model identified patients who developed recurrence with an area under the curve of 75.9% in the discovery cohort and 69.5% in a separate validation cohort (n=33) to predict recurrence status at 1 year.ConclusionsAdjuvant immunotherapy-treated patients with a high proportion of CD39+ Trms in their baseline melanoma resection have a significantly reduced risk of melanoma recurrence. This population of T cells may not only represent a biomarker of RFS following anti-PD-1 therapy, but may also be an avenue for therapeutic manipulation and enhancing outcomes for immunotherapy-treated patients with cancer.

9539 Background: Neoadjuvant IPI + NIVO induces high pathologic response rates (pRR) of 74-78% in macroscopic stage III melanoma. Pathologic response ( < 50% viable tumor) is strongly associated with improved relapse-free survival (RFS); the previous OpACIN-neo study demonstrated a 2-year RFS of 96.9% in patients (pts) with pathologic response, whereas the 2-year RFS in non-responders was 35.5%. These data highlight the need for baseline biomarkers predictive for response and survival. Here, we present the predictive value of the 10-gene IFN-y expression signature algorithm (based on Ayers et al.) for pathologic response and relapse in a cohort of melanoma pts treated with neoadjuvant IPI + NIVO. Methods: Baseline tumor biopsies from lymph node metastases of stage III melanoma pts were used for IFN-y signature assessment. Pts were treated with a maximum of two cycles of neoadjuvant IPI 1mg/kg + NIVO 3mg/kg in the OpACIN-neo (arm B) and PRADO studies. RNA expression analysis was conducted using the nCounter® PanCancer Immune Profiling panel on the NanoString Flex machine (NanoString Technologies), which is clinically applicable due to its fast turn-around-time (two days). An IFN-y signature gene expression score (IFN-y score) was calculated using a NKI-developed algorithm. Association between IFN-y score and pathologic response or event-free survival (EFS) was examined by logistic regression and Cox analyses. The optimal cutoff between a high and low IFN-y score was defined based on a summary receiver operating characteristic (sROC) curve. Results: In total, 103 pts treated in the OpACIN-neo and PRADO studies had baseline tumor material available. Median age was 56 years, 62% was male, and 52% had a high baseline IFN-y score. The pRR of the total cohort was 70% (72/103 pts), including 56% (58/103) major pathologic response (MPR, 0-≤10% viable tumor) and 14% (14/103) partial responses (pPR, 10-≤50% viable tumor). 30% (31/103 pts) had no pathologic response. After a median follow-up of 25.2 months, 26 pts (25.2%) developed a melanoma relapse. The IFN-y score was significantly associated with response (OR 1.061, p < 0.001) and relapse (OR 0. 974, p = 0.029). The pRR was 89% (48/54) in pts with a high IFN-y score versus 49% (24/49) in those with a low IFN-y score (p < 0.001). Pts with a high IFN-y score were also less likely to develop a relapse (11% [6/54] versus 41% [20/49], p = 0.001). Conclusions: Pts with a high IFN-y score in pre-treatment biopsies are more likely to respond to neoadjuvant IPI + NIVO with favorable EFS. A rapid gene expression analysis enables the IFN-y score to be used in daily clinical practice to identify pts who might qualify for treatment escalation or de-escalation. The DONIMI study [NCT04133948] currently investigates different neoadjuvant treatment combinations in stage III melanoma pts based on their intratumoral IFN-y score.

TPS9605 Background: Adjuvant treatment with anti-PD1 therapy improves the recurrence free survival (RFS) in resectable stage III melanoma. The Checkmate-238 and KEYNOTE-054 trials respectively reported a 4-year RFS of 52.5% for adjuvant nivolumab and a 3-year RFS of 63.7% for adjuvant pembrolizumab. Despite these improved outcomes, a considerable proportion of patients have a relapse in the years after therapeutic lymph node dissection (TLND). The OpACIN trial showed that neoadjuvant treatment with nivolumab (NIVO) plus ipilimumab (IPI) is feasible and induces a stronger and broader T-cell response. The subsequent OpACIN-neo trial identified 2 cycles of NIVO 3mg/kg + IPI 1mg/kg as a neoadjuvant dosing scheme with decreased toxicity and preserved high pathologic response rates (77%), which was confirmed in the PRADO trial. A favorable 2-year RFS (83,6%) was achieved in the overall OpACIN-neo population, although patients with a pathological partial or non-response have a worse prognosis and may therefore benefit from additional adjuvant therapy. The efficacy of neoadjuvant checkpoint inhibition versus the current standard of adjuvant therapy needs to be confirmed in a phase III trial, before neoadjuvant therapy can be considered as a standard option for this patient population. Methods: This international, randomized phase 3 trial aims to compare the efficacy of neoadjuvant IPI + NIVO with adjuvant NIVO in macroscopic stage III melanoma. In total 420 patients diagnosed with recurrent or de novo melanoma, with at least one pathologically proven, clinically detectable lymph node (up to 3 in-transit metastases (ITMs) allowed), will be randomized to neoadjuvant or adjuvant treatment. The population will be stratified by BRAF mutation, continent and the presence of ITMs. Patients in arm A will receive 2 cycles of IPI 80mg + NIVO 240mg and will undergo TLND at week 6. In the case of pathological partial response or non-response, surgery will be followed by adjuvant NIVO (11 cycles) or adjuvant dabrafenib + trametinib (46 weeks) if BRAFV600-mutation is present. Patients in arm B will undergo upfront TLND followed by 12 cycles of NIVO 480mg. The primary endpoint will be the event free survival (EFS) defined as the time from randomization until progression to unresectable stage III or stage IV melanoma, recurrent melanoma, a new primary melanoma or death due to melanoma or treatment. Final analysis will be performed after 132 events have been observed, or at latest 2 years after the last patient is included. Baseline biopsies and blood samples (screening, week 0, 3, 6, 9 and 12) will be collected for translational research. Quality of Life questionnaires and electronic Patient Reported Outcomes will be collected using the Kaiku application. The first patient was enrolled on the 23rd of July 2021. Clinical trial information: NCT04949113.

9503 Background: Combination anti-PD(L)1 and BRAF/MEK-targeted therapy (TT) improves PFS in stage IV melanoma vs TT. In stage IV melanoma recent data suggest immunotherapy 1st until progression, rather than BRAF-TT, improves OS, and induction TT upfront adds little benefit. NeoTrio explored the optimal combination of BRAF-TT and anti-PD1 using the NAT platform in pts with stage III melanoma (NCT02858921). Methods: 60 pts with resectable, RECIST measurable stage III (no in-transit) BRAFV600-mutant melanoma were randomized 1:1:1 to 3 arms of 6 wks of NAT followed by complete lymph node dissection (CLND): A) Pembro ALONE (200mg Q3W x 2); B) SEQ - D+T (150mg bd + 2mg od) for 1 wk followed by pembro (200mg x 2); C) CON – D+T+pembro (doses as SEQ). Pts had 46 wks pembro post-CLND. Primary endpoint was the pathological response rate (pRR) and pathological complete response (pCR) at wk 6. Secondary endpoints; RECIST RR at wk 6, event-free survival (EFS), RFS, OS, adverse events (AE) and translational endpoints. Results: At data cutoff 2 Jan 2022, 20 pts per arm had similar baseline characteristics; overall 42% female, med age 53 yrs, 82% BRAF V600E, 62% clinical N1b. Med f/u was 20 months (95% CI 17-31). The pCR rate and pRR were highest in CON arm, and similar in ALONE and SEQ arms (Table). Events (progression before surgery, recurrence after surgery or death) were highest in ALONE arm at this 1st analysis (Table). Assessment of the durability of path response subtypes in each arm is ongoing. Most common Rx related AE were fatigue (65%, 70%, 70%, ALONE, SEQ and CON respectively), pyrexia (0%, 25%, 85%) and rash (50%, 35%, 35%). Gd 3/4 AE occurred in 30%, 25% and 55%, respectively; pyrexia and hepatitis were common in CON during NAT. Rx interruptions during NAT occurred in 0, 3 and 19 pts, respectively; 1, 0 and 8 pts permanently discontinued. Post NAT surgical operability was the same or improved in 81%. Longitudinal analysis of melanoma tissue, microenvironment and microbiome is ongoing. Conclusions: CON D+T+pembro achieved the highest pRR, pCR rate, but with greater toxicity. Recurrences were seen in those with pCR/near pCR in BRAF-TT containing arms, but not in pembro ALONE, in keeping with previous data of NAT with checkpoint inhibitors vs BRAF-TT. Short course of D+T prior to PD1 did not improve path response, despite previous translational data showing increased tumour infiltrating T-cells early-during treatment with D+T. Follow up is ongoing. Clinical trial information: NCT02858921. [Table: see text]

9501 Background: In the OpACIN-neo study, 2 cycles neoadjuvant (neoadj) IPI 1mg/kg + NIVO 3mg/kg (I1N3) have been identified as most favorable dosing scheme with a pathologic response rate (pRR) of 77% and 20% grade 3-4 irAEs. After 24.6 months median follow-up (FU), the 2-year (2y) RFS was 96.9% for patients (pts) with pathologic response versus 35.5% for non-responders (>50% viable tumor; pNR). These data raised the question whether therapeutic lymph node dissection (TLND) could be safely omitted in pts achieving a major pathologic response (MPR; ≤10% viable tumor) in their index node (ILN; largest LN metastasis at baseline), and if additional adjuvant (adj) therapy could improve the outcome of pNR pts. Methods: PRADO is an extension cohort of the phase 2 OpACIN-neo study aiming to confirm the pRR and safety of neoadj I1N3 and to test response-driven subsequent therapy. Pts with stage III melanoma were included to receive 2 cycles neoadj I1N3 after marker placement in the ILN. ILN resection was planned at week 6. Pts that achieved MPR in the ILN did not undergo TLND; pts with partial response (pPR; >10 – ≤50% viable tumor) underwent TLND; and pts with pNR underwent TLND and received adj NIVO or dabrafenib plus trametinib (D+T) for 52 weeks ±radiotherapy (RT). Primary endpoints were pRR in the ILN and RFS at 2y. The 2y RFS rates were calculated using a Kaplan Meier based method. Results: Between Nov 2018 and Jan 2020, 99 patients were enrolled and treated with at least 1 cycle of neoadj I1N3. We previously showed a pRR of 72% (95% CI 62 - 80), including 60 (61%) pts with MPR and 11 (11%) pts with pPR. TLND omission in MPR pts resulted in significant reduced surgical morbidity and improved quality of life. There were 27 non-responders of whom 6 developed distant metastasis before ILN resection. Of the other 21 pNR pts, 7 received adj NIVO, 10 adj D+T, 3 no adj therapy, and 1 was lost to FU. After a median FU of 27.9 months (data cutoff Jan 31, 2022), the estimated 2y RFS rate for MPR pts was 93.3% (95% CI 87.2 – 99.9), with 4/60 pts developing a regional relapse. Distant metastasis-free survival (DMFS) was 100%. Of the 11 pPR pts, 4 developed a relapse (all distant), resulting in a 2y RFS and DMFS rate of 63.6% (95% CI 40.7 – 99.5). The 2y RFS rate of the pNR pts was 71.4% (95% CI 54.5 – 93.6), and DMFS 76.2%. At data cutoff, relapse occurred in 2/7 pNR pts with adj NIVO and 3/10 with adj D+T. Final data cutoff is planned mid Feb, 2022. Conclusions: MPR pts in whom TLND was omitted showed a 2y RFS rate of 93.3% and DMFS of 100%, indicating that the ILN procedure and omitting adj therapy could become a safe approach in these pts. Adj systemic therapy in pNR pts seems to improve RFS as compared to historic control (OpACIN-neo), thus should be considered in this unfavorable pNR group. The DMFS rate of 63.6% observed in the pPR group advocates the consideration of adj therapy also for this subgroup in the future. Clinical trial information: NCT02977052.