Search

Oncolytic virus therapies induce the direct killing of tumor cells and activation of conventional dendritic cells (cDC); however, cDC activation has not been optimized with current therapies. We evaluated the adenoviral delivery of engineered membrane-stable CD40L (MEM40) and IFNβ to locally activate cDCs in mouse tumor models. Combined tumor MEM40 and IFNβ expression induced the highest cDC activation coupled with increased lymph node migration, increased systemic antitumor CD8+ T-cell responses, and regression of established tumors in a cDC1-dependent manner. MEM40 + IFNβ combined with checkpoint inhibitors led to effective control of distant tumors and lung metastases. An oncolytic adenovirus (MEM-288) expressing MEM40 + IFNβ in phase I clinical testing induced cancer cell loss concomitant with enhanced T-cell infiltration and increased systemic presence of tumor T-cell clonotypes in non–small cell lung cancer (NSCLC) patients. This approach to simultaneously target two major DC-activating pathways has the potential to significantly affect the solid tumor immunotherapy landscape.

OBJECTIVE Immune checkpoint inhibitors (ICIs) and epidermal growth factor receptor–tyrosine kinase inhibitors (EGFR-TKIs) are commonly used in the systemic management of non–small cell lung cancer (NSCLC) brain metastases (BMs). However, optimizing control of NSCLC BM with stereotactic radiosurgery (SRS) and various systemic therapies remains an area of investigation. METHODS Between 2016 and 2019, the authors identified 171 NSCLC BM patients with 646 BMs treated with single-fraction SRS within 3 months of receiving treatment with ICIs (n = 56; 33%), EGFR-TKI (n = 30; 18%), chemotherapy and ICIs (n = 23; 14%), or standard chemotherapy alone (n = 62; 36%). Time-to-event analysis was conducted, and outcomes included distant intracranial control (DIC), local control (LC), and overall survival from SRS. RESULTS The median follow-up from BM diagnosis was 8.9 months (range 0.3–127 months). The 12-month Kaplan-Meier DIC rates were 37%, 53%, 41%, and 21% (p = 0.047) for the ICI, EGFR-TKI, ICI and chemotherapy, and chemotherapy-alone groups, respectively. On multivariate analysis, DIC was improved with EGFR-TKI (HR 0.4, 95% CI 0.3–0.8, p = 0.005) compared with conventional chemotherapy and treatment with SRS before systemic therapy (HR 0.5, 95% CI 0.3–0.9, p = 0.03) compared with after; and LC was improved with SRS before (HR 0.4, 95% CI 0.2–0.9, p = 0.03) or concurrently (HR 0.3, 95% CI 0.1–0.6, p = 0.003) compared with after. No differences in radionecrosis were noted by timing or type of systemic therapy. CONCLUSIONS The authors’ analysis showed significant differences in DIC based on receipt of systemic therapy and treatment with SRS before systemic therapy improved DIC. Prospective evaluation of the potential synergism between systemic therapy and SRS in NSCLC BM management is warranted.

Merkel cell carcinoma is among the most aggressive and lethal of primary skin cancers, with a high rate of distant metastasis. Anti-programmed death receptor 1 (anti-PD-1) and programmed death ligand 1 (PD-L1) monotherapy is currently standard of care for unresectable, recurrent, or metastatic Merkel cell carcinoma. We assessed treatment with combined nivolumab plus ipilimumab, with or without stereotactic body radiotherapy (SBRT) in patients with advanced Merkel cell carcinoma as a first-line therapy or following previous treatment with anti-PD-1 and PD-L1 monotherapy.In this randomised, open label, phase 2 trial, we randomly assigned adults from two cancer sites in the USA (one in Florida and one in Ohio) to group A (combined nivolumab and ipilimumab) or group B (combined nivolumab and ipilimumab plus SBRT) in a 1:1 ratio. Eligible patients were aged at least 18 years with histologically proven advanced stage (unresectable, recurrent, or stage IV) Merkel cell carcinoma, a minimum of two tumour lesions measureable by CT, MRI or clinical exam, and tumour tissue available for exploratory biomarker analysis. Patients were stratified by previous immune-checkpoint inhibitor (ICI) status to receive nivolumab 240 mg intravenously every 2 weeks plus ipilimumab 1 mg/kg intravenously every 6 weeks (group A) or the same schedule of combined nivolumab and ipilimumab with the addition of SBRT to at least one tumour site (24 Gy in three fractions at week 2; group B). Patients had to have at least two measurable sites of disease so one non-irradiated site could be followed for response. The primary endpoint was objective response rate (ORR) in all randomly assigned patients who received at least one dose of combined nivolumab and ipilimumab. ORR was defined as the proportion of patients with a complete response or partial response per immune-related Response Evaluation Criteria in Solid Tumours. Response was assessed every 12 weeks. Safety was assessed in all patients. This trial is registered with ClinicalTrials.gov, NCT03071406.50 patients (25 in both group A and group B) were enrolled between March 14, 2017, and Dec 21, 2021, including 24 ICI-naive patients (13 [52%] of 25 group A patients and 11 [44%] of 25 group B patients]) and 26 patients with previous ICI (12 [48%] of 25 group A patients and 14 [56%] of 25 group B patients]). One patient in group B did not receive SBRT due to concerns about excess toxicity. Median follow-up was 14·6 months (IQR 9·1-26·5). Two patients in group B were excluded from the analysis of the primary endpoint because the target lesions were irradiated and so the patients were deemed non-evaluable. Of the ICI-naive patients, 22 (100%) of 22 (95% CI 82-100) had an objective response, including nine (41% [95% CI 21-63]) with complete response. Of the patients who had previously had ICI exposure, eight (31%) of 26 patients (95% CI 15-52) had an objective response and four (15% [5-36]) had a complete response. No significant differences in ORR were observed between groups A (18 [72%] of 25 patients) and B (12 [52%] of 23 patients; p=0·26). Grade 3 or 4 treatment-related adverse events were observed in 10 (40%) of 25 patients in group A and 8 (32%) of 25 patients in group B.First-line combined nivolumab and ipilimumab in patients with advanced Merkel cell carcinoma showed a high ORR with durable responses and an expected safety profile. Combined nivolumab and ipilimumab also showed clinical benefit in patients with previous anti-PD-1 and PD-L1 treatment. Addition of SBRT did not improve efficacy of combined nivolumab and ipilimumab. The combination of nivolumab and ipilimumab represents a new first-line and salvage therapeutic option for advanced Merkel cell carcinoma.Bristol Myers Squibb Rare Population Malignancy Program.

Supplementary Figures 1-14

Supplementary Table 1

Supplementary Table Legends

Supplementary Table 3

Supplementary Table 2

Oncolytic virus therapies induce the direct killing of tumor cells and activation of conventional dendritic cells (cDC); however, cDC activation has not been optimized with current therapies. We evaluated the adenoviral delivery of engineered membrane-stable CD40L (MEM40) and IFNβ to locally activate cDCs in mouse tumor models. Combined tumor MEM40 and IFNβ expression induced the highest cDC activation coupled with increased lymph node migration, increased systemic antitumor CD8+ T-cell responses, and regression of established tumors in a cDC1-dependent manner. MEM40 + IFNβ combined with checkpoint inhibitors led to effective control of distant tumors and lung metastases. An oncolytic adenovirus (MEM-288) expressing MEM40 + IFNβ in phase I clinical testing induced cancer cell loss concomitant with enhanced T-cell infiltration and increased systemic presence of tumor T-cell clonotypes in non–small cell lung cancer (NSCLC) patients. This approach to simultaneously target two major DC-activating pathways has the potential to significantly affect the solid tumor immunotherapy landscape.

Supplementary Data from Olfactory Receptor OR2H1 Is an Effective Target for CAR T Cells in Human Epithelial Tumors

Supplementary Figure from Olfactory Receptor OR2H1 Is an Effective Target for CAR T Cells in Human Epithelial Tumors

Purpose: This joint guideline by American Society for Radiation Oncology (ASTRO) and the European Society for Radiotherapy and Oncology (ESTRO) was initiated to review evidence and provide recommendations regarding the use of local therapy in the management of extracranial oligometastatic non-small cell lung cancer (NSCLC). Local therapy is defined as the comprehensive treatment of all known cancer—primary tumor, regional nodal metastases, and metastases—with definitive intent. Methods: ASTRO and ESTRO convened a task force to address 5 key questions focused on the use of local (radiation, surgery, other ablative methods) and systemic therapy in the management of oligometastatic NSCLC. The questions address clinical scenarios for using local therapy, sequencing and timing when integrating local with systemic therapies, radiation techniques critical for oligometastatic disease targeting and treatment delivery, and the role of local therapy for oligoprogression or recurrent disease. Recommendations were based on a systematic literature review and created using ASTRO guidelines methodology. Results: Based on the lack of significant randomized phase 3 trials, a patient-centered, multidisciplinary approach was strongly recommended for all decision-making regarding potential treatment. Integration of definitive local therapy was only relevant if technically feasible and clinically safe to all disease sites, defined as 5 or fewer distinct sites. Conditional recommendations were given for definitive local therapies in synchronous, metachronous, oligopersistent, and oligoprogressive conditions for extracranial disease. Radiation and surgery were the only primary definitive local therapy modalities recommended for use in the management of patients with oligometastatic disease, with indications provided for choosing one over the other. Sequencing recommendations were provided for systemic and local therapy integration. Finally, multiple recommendations were provided for the optimal technical use of hypofractionated radiation or stereotactic body radiation therapy as definitive local therapy, including dose and fractionation. Conclusions: Presently, data regarding clinical benefits of local therapy on overall and other survival outcomes is still sparse for oligometastatic NSCLC. However, with rapidly evolving data being generated supporting local therapy in oligometastatic NSCLC, this guideline attempted to frame recommendations as a function of the quality of data available to make decisions in a multidisciplinary approach incorporating patient goals and tolerances.

Although chimeric antigen receptor (CAR)-expressing T cells have proven success in hematologic malignancies, their effectiveness in solid tumors has been largely unsuccessful thus far. We found that some olfactory receptors are expressed in a variety of solid tumors of different histologic subtypes, with a limited pattern of expression in normal tissues. Quantification of OR2H1 expression by qRT-PCR and Western blot analysis of 17 normal tissues, 82 ovarian cancers of various histologies, eight non–small cell lung cancers (NSCLCs), and 17 breast cancers demonstrated widespread OR2H1 expression in solid epithelial tumors with expression in normal human tissues limited to the testis. CAR T cells recognizing the extracellular domain of the olfactory receptor OR2H1 were generated with a targeting motif identified through the screening of a phage display library and demonstrated OR2H1-specific cytotoxic killing in vitro and in vivo, using tumor cells with spontaneous expression of variable OR2H1 levels. Importantly, recombinant OR2H1 IgG generated with the VH/VL sequences of the CAR construct specifically detected OR2H1 protein signal in 60 human lung cancers, 40 ovarian carcinomas, and 73 cholangiocarcinomas, at positivity rates comparable with mRNA expression and without OR2H1 staining in 58 normal tissues. CRISPR/Cas9-mediated ablation of OR2H1 confirmed targeting specificity of the CAR and the tumor-promoting role of OR2H1 in glucose metabolism. Therefore, T cells redirected against OR2H1-expressing tumor cells represent a promising therapy against a broad range of epithelial cancers, likely with an admissible toxicity profile.

Purpose Consolidative thoracic radiation therapy (TRT) has been shown to improve outcomes for patients with extensive stage small cell lung cancer. We hypothesized that the addition of ipilimumab (IPI) and nivolumab (NIVO) after TRT would improve outcomes for patients with extensive stage small cell lung cancer. Methods and Materials Eligibility required stable disease or better after platinum doublet chemotherapy. Study therapy included consolidative TRT to 30 Gy in 10 fractions, targeting residual primary tumor and initially involved regional lymph nodes. Two weeks after TRT, patients received concurrent IPI (3 mg/kg) and NIVO (1 mg/kg) every 3 weeks for 4 doses followed by NIVO monotherapy (480 mg) every 4 weeks until progression or up to 1 year. Results The study enrolled 21 patients, with 6-month progression-free survival (PFS) of 24% (90% confidence interval [CI], 11%-40%) and a median PFS of 4.5 months (95% CI, 2.7%-4.6%). The 12-month overall survival (OS) was 48% (95% CI, 29%-64%) with a median OS of 11.7 months (95% CI, 4.7%-16.0%). Fifty-two percent of patients had ≥1 possibly related grade 3 to 4 immune-related adverse event. Grade 3 pulmonary and gastrointestinal immune-related adverse events were recorded in 19% and 24% of patients, respectively. Exploratory analysis showed increased cytotoxic T cell (CD3+CD8+) tumor infiltration was associated with favorable PFS (P = .01) and OS (P = .02). Reduction in peripheral blood CD3+CD8+ from baseline to after first dose of IPI/NIVO was associated with improved PFS (P = .02) and OS (P = .02). Conclusions Consolidative IPI and NIVO after platinum-based chemotherapy and TRT demonstrated a toxicity profile consistent with the known adverse events attributable to IPI and NIVO. Although the study regimen did not significantly improve PFS, the OS was higher than historic expectations. CD3+CD8+ tumor infiltration and migration may identify patients most likely to have improved outcomes in small cell lung cancer.

Despite repeated associations between T cell infiltration and outcome, human ovarian cancer remains poorly responsive to immunotherapy. We report that the hallmarks of tumor recognition in ovarian cancer-infiltrating T cells are primarily restricted to tissue-resident memory (TRM) cells. Single-cell RNA/TCR/ATAC sequencing of 83,454 CD3(+) CD8(+)CD103(+)CD69(+) TRM cells and immunohistochemistry of 122 high-grade serous ovarian cancers shows that only progenitor (TCF1(low)) tissue-resident T cells (TRMstem cells), but not recirculating TCF1(+) T cells, predict ovarian cancer outcome. TRMstem cells arise from transitional recirculating T cells, which depends on antigen affinity/persistence, resulting in oligoclonal, trogocytic, effector lymphocytes that eventually become exhausted. Therefore, ovarian cancer is indeed an immunogenic disease, but that depends on similar to 13% of CD8(+) tumor-infiltrating T cells (similar to 3% of CD8(+) clonotypes), which are primed against high-affinity antigens and maintain waves of effector TRM-like cells. Our results define the signature of relevant tumor-reactive T cells in human ovarian cancer, which could be applicable to other tumors with unideal mutational burden.

Background: Epidermal growth factor receptor (EGFR) mutated non-small cell lung cancer (NSCLC) shows an impressive initial response to EGFR tyrosine kinase inhibitors (EGFR-TKI). However, resistance invariably develops, commonly involving the site of initial gross disease. Cytoreductive stereotactic body radiotherapy (SBRT) for thoracic oligoprogressive disease (OPD) may effectively delay progression through EGFR-TKI therapy.Methods: From a prospectively maintained IRB-approved institutional registry, we identified 23 patients consecutively treated between 2011-2019 with thoracic SBRT and received EGFR-TKI within 6-months of SBRT. Radiographic progression-free (PFS) and overall survival (OS) were estimated using Kaplan-Meier analysis. Toxicity and patient-reported Edmonton Symptom Assessment Scale (ESAS) scores were reviewed.Results: Median follow-up after SBRT was 20-months (range, 4-100), and the median age was 68-years (range, 33-89). Most patients were females (n=21;91.3%). RT dose was 50-60 Gy in 5-10 fractions. EGFR-TKI administered were erlotinib, osimertinib and gefitinib in 15, 5, and 3 patients, respectively. Median PFS and OS following SBRT were 8-months and 31-months, respectively. 1-year PFS and OS were 34.8% and 78.3%. The median duration of EGFR-TKI therapy was 26-months (1-91). Most patients progressed in new distant sites, most commonly bones (n=5;21.7%) and distant lung (n=4;17.4%), with only 2/23 patients having initial progression within the SBRT field. Grade-2 pneumonitis (n=2) and rib fracture (n=1) were noted radiation-related toxicities. Dominant ESAS symptoms were fatigue (21.7%), pain (8.7%), and loss of appetite (8.7%).Conclusions: For EGFR-mutated NSCLC patients with thoracic OPD on EGFR-TKI, SBRT was well tolerated, resulted in changes in subsequent patterns of failure, lengthened PFS, and prolongs the duration of initial TKI therapy.

Simple Summary Non-small cell lung cancer accounts for 80% of all lung cancer cases. While a subset of non-small cell lung cancer patients respond to immunotherapy, those who are treated with chemotherapy or targeted therapy develop resistance to the drugs. Thus, novel therapeutic strategies are needed to combat this disease. Here we show that inhibitors of the cyclin-dependent kinase 9 are highly effective in preventing the growth of a variety of lung cancer cell lines and lung cancer organoids with high potency. These inhibitors suppressed the expression of several genes like Sox2, Sox9, and Mcl1 that promote tumor growth, facilitating growth arrest. Since inhibitors of cyclin-dependent kinase 9 are undergoing clinical trials for hematological malignancies, our studies suggest that these inhibitors would be attractive candidates to combat non-small cell lung cancer. Abstract Non-small cell lung cancer has a 5-year survival rate of less than 12–15%, calling for the development of additional therapeutic strategies to combat this disease. Here we tested the efficacy of inhibiting cyclin-dependent kinase 9 (CDK9) on lung cancer cell lines with K-Ras and EGFR mutations and on lung cancer organoids. Three different CDK9 inhibitors reduced the viability and anchorage-independent growth of lung cancer cell lines at very low nanomolar to micromolar concentrations. CDK9 inhibition suppressed the expression of the anti-apoptotic protein, Mcl1, as well as the embryonic stem cell transcription factors, Sox2 and Sox9, which are pro-tumorigenic. In contrast, treatment with CDK9 inhibitors increased the levels of WT p53 and its downstream target p21 in K-Ras mutant cell lines. Furthermore, the CDK9 inhibitors could markedly reduce the viability of Osimertinib-resistant PC9 and AMG510-resistant H23 and H358 cells with comparable efficacy as the parental cells. CDK9 inhibitors could also significantly reduce the growth and viability of lung cancer organoids with high potency. Taken together, the data presented here strongly suggest that CDK9 inhibitors would be efficacious against K-Ras mutant and EGFR mutant NSCLCs, including those that develop resistance to targeted therapies.

Purpose/Objective(s) We hypothesized that the addition of concurrent ipilimumab (IPI) with chemoradiotherapy followed by consolidative nivolumab (NIVO) would be safe and tolerable for patients with unresectable stage III non-small cell lung cancer (NSCLC). We report early outcomes and toxicity associated with this regimen in a phase I/II clinical trial. Materials/Methods The study was designed as a prospective, multicenter phase I/II trial. Eligible patients had ECOG 0-1 and unresectable stage III NSCLC. Therapy included a platinum-based chemotherapy doublet with concurrent radiotherapy to 60 Gy in 30 fractions over six weeks and two doses of concurrent IPI (1 mg/kg) given weeks 1 and 4. Maintenance NIVO was initiated 1-3 weeks after completion of chemoradiotherapy/IPI and given every 4 weeks (480 mg) for up to 12 cycles. The primary endpoints were to evaluate the safety and tolerability of the regimen (Phase I) and the 12-month PFS (Phase II). Treatment-related toxicity was assessed according to CTCAE v5.0. Time to event analysis was performed with Kaplan Meier (KM) and Cox proportional hazard (CPH) models. Results are reported with 95% confidence intervals (CI). Results Nineteen of a planned 55 patients were enrolled in the trial which was discontinued without proceeding to the Phase II component due to exceeding the futility boundary for toxicity. The median follow-up was 21 months by the reverse KM method. The 12-month PFS estimate was 54% (CI 29-78) and the median PFS was 19 months (CI 6-not reached). The 12-month OS estimate was 60% (CI 36-84) while the median OS was not reached. Ten patients (53%, CI 29-76) experienced grade 2 or higher (G2+) pneumonitis. The median time to development of G2+ pneumonitis was 5.5 months and the risk of G2+ pneumonitis at 6- and 12-months was 57% (CI 30-84) and 74% (CI 49-99), respectively. Sixteen patients (84%, CI 68-100) had any G3+ treatment related toxicity. The most common G3+ toxicities were pulmonary (8 patients, 42%, CI 20-67) and cytopenias (7 patients, 37%, CI 16-62). Five patients (26%, CI 6-46) had possible treatment related G5 toxicity, including three patients with possible treatment related G5 pulmonary toxicity (16%, CI 0-32). There was no difference in the mean percent of lung volume receiving 20 Gy (V20) between those with and without G2+ pneumonitis (26%, CI 20-32 vs 21%, CI 16-27, P = 0.18), nor in the mean lung dose (14 Gy, CI 10-17 vs 15 Gy, CI 12-18, P = 0.35). Neither mean lung dose nor lung V20 were associated with time to G2+ pneumonitis on univariable CPH. Conclusion The combination of concurrent IPI with standard chemoradiation followed by maintenance NIVO for unresectable stage III NSCLC is associated with significant toxicity which may limit opportunities for improved outcomes, although the sample size in this trial is small. Alternative strategies or sequencing should be explored to integrate immunotherapy with cytotoxic chemotherapy and radiation for patients with unresectable stage III NSCLC.

BackgroundWe hypothesized that the radiosensitivity index (RSI), would classify non-small cell lung cancer (NSCLC) patients into radioresistant (RR) or radiosensitive (RS).MethodsWe identified resected pathologic stage III NSCLC. For the radiation group (RT) group, at least 45 Gy of external beam radiation was required. mRNA was extracted from primary tumor. The predefined cut-point was the median RSI with a primary endpoint of local control. Similar criteria were then applied to two extramural datasets (E1; E2) with progression free survival as the primary endpoint.ResultsMedian follow-up from diagnosis was 23.5 months (range: 4.8-169.6 months). RSI was associated with time to local failure in the RT group with a two-year rate of local control of 80% and 56% between RS and RR groups, respectively p=0.02. RSI was the only variable found to be significant on Cox local control analysis (HR 2.9; 95% CI: 1.2-8.2; p=0.02). There was no significance of RSI in predicting local control in patients not receiving RT, p=0.48. A cox regression model between receipt of radiotherapy and RSI combining E1 and E2 showed that the interaction term was significant for PFS (3.7; 95% CI 1.4-10; p=0.009). A summary measure combining E1 and E2 showed statistical significance for PFS between RR and RS patients treated with radiotherapy (HR 2.7l; 95% CI 1.3-5.6; p=0.007) but not in patients not treated with radiotherapy (HR 0.94; 95% CI 0.5-1.78; p=0.86).ConclusionsRSI appears to be predictive for benefit from adjuvant radiation. Prospective validation is required.

Tertiary Lymphoid Structures (TLS) are commonly identified in human tumors with improved outcome, but how they are orchestrated remains elusive. We show that ablation of the genomic organizer SATB1 triggers the polarization of CD4+ T-cells into antigen-specific T Follicular Helper (TFH) cells. In contrast, SATB1 expression is required for conversion of CD4+ T-cells into induced regulatory T-cells (Treg), including T Follicular Regulatory (TFR) cells. Paradoxically, Tgf-β-driven Satb1 silencing causes Icos de-repression and prevents TFR differentiation, driving TFH polarization and increased isotype-switched B cell responses. Tumors in mice carrying Satb1-deficient CD4+ T-cells accumulate more tumor antigen-specific, Light/Cxcl13/Il-21-producing TFH cells, causing germinal center formation and spontaneous TLS assembly, which antagonizes tumor growth. Accordingly, TFH cell transfer induces large TLS within orthotopic ovarian tumors. Therefore, SATB1 repression in CD4+ T-cells licenses TFH cell differentiation while preventing Treg conversion, a central mechanism during TLS assembly that can be exploited to boost anti-tumor immunity.

Introduction: The PACIFIC trial demonstrated that durvalumab significantly improved progression-free and overall survival (PFS/OS), versus placebo, in patients with Stage III NSCLC and stable or responding disease following concurrent, platinum-based chemoradiotherapy (CRT). A range of CT and RT regimens were permitted, and used, in the trial. We report post-hoc, exploratory analyses of clinical outcomes from PACIFIC according to CRT-related variables. Methods: Patients were randomized 2:1 (1-42 days post-CRT) to up to 12 months durvalumab (10 mg/kg intravenously every 2 weeks) or placebo. Efficacy and safety were analyzed in patient subgroups defined by the following baseline variables: platinum-based CT (cisplatin/carboplatin); vinorelbine, etoposide, or taxane-based CT (all yes/no); total RT dose (66 Gy); time from last RT dose to randomization (= 14 days); and use of pre-CRT induction CT (yes/no). Treatment effects for time-to-event endpoints were estimated by hazard ratios (HRs) from unstratified Cox-proportional-hazards models. Results: Overall, 713 patients were randomized, of whom 709 received treatment in either the durvalumab (n/N = 473/476) or placebo arms (n/N = 236/237). Durvalumab improved PFS, versus placebo, across all subgroups (median follow up, 14.5 months; HR range, 0.34-0.63). Durvalumab improved OS across most subgroups (median follow up, 25.2 months; HR range, 0.35-0.86); however, the 95 % confidence interval (CI) of the estimated treatment effect crossed one for the subgroups of patients who received induction CT (HR, 0.78 [95 % CI, 0.51-1.20]); carboplatin (0.86 [0.60-1.23]); vinorelbine (0.79 [0.49-1.27]); and taxane-based CT (0.73 [0.51-1.04]); and patients who were randomized >= 14 days post-RT (0.81 [0.62-1.06]). Safety was broadly similar across the CRT subgroups. Conclusion: Durvalumab prolonged PFS and OS irrespective of treatment variables related to prior CRT to which patients with Stage III NSCLC had previously stabilized or responded. Limited patient numbers and imbalances in baseline factors in each subgroup preclude robust conclusions. AstraZenecaAstraZeneca; NIHR Manchester Biomedical Research CentreNational Institute for Health Research (NIHR) Medical writing support during the preparation of this manuscript, which was in accordance with Good Publication Practice (GPP3) guidelines, was provided by Aaron Korpal, PhD, of Cirrus Communications (Manchester, UK), an Ashfield company, and was funded by AstraZeneca. Professor Corinne Faivre-Finn is supported by a grant from the NIHR Manchester Biomedical Research Centre.

Despite repeated associations between T-cell infiltration and patient outcome, human ovarian cancer remains poorly responsive to immunotherapy. We report that hallmarks of tumor recognition in ovarian cancer-infiltrating T-cells are primarily restricted to tissue-resident memory (TRM) cells. In mouse models we found that TRM T-cells were better than the re-circulating counterpart at controlling tumor growth. Single-cell RNA/TCR/ATAC sequencing of 83,454 CD3+CD8+CD103+CD69+ TRM cells and 24,175 CD3+CD8+CD103− re-circulating TILs showed that progenitor (TCF1low) tissue-resident memory T-cells (TRMstem cells) arise from transitional recirculating T-cells, which depends on antigen affinity/persistence, resulting in oligoclonal, trogocytic, effector lymphocytes. This effector population develops into proliferative lymphocytes that eventually become exhausted TRMs. Immunohistochemistry of 122 high-grade serous ovarian cancer tissues showed that only TRMstem cells, but not re-circulating TCF1+ T-cells, predict ovarian cancer outcome. Therefore, ovarian cancer is indeed an immunogenic disease that depends on ~13% of CD8+ tumor-infiltrating T-cells (~3% of CD8+ clonotypes), which are primed against high-affinity antigens and maintain waves of effector TRM cells. Support for Shared Resources was provided by Cancer Center Support Grant (CCSG) CA076292 to H. Lee Moffitt Cancer Center and by CCSG CA010815 to The Wistar Institute. This study was supported by grants from NIH (R01CA157664, R01CA124515, R01CA178687, R01CA211913 and U01CA232758 to JRCG; R01CA184185 and RO1CA262121 to PCR.)

Chimeric antigen receptor (CAR) T cells have been successful for hematological malignancies, but so far showed limited efficiency against solid tumors. Olfactory receptors are expressed in a variety of epithelial cancers, with a limited expression in healthy tissues. We quantified olfactory receptor OR2H1 expression in ovarian cancer, non-small cell lung cancer (NSCLC), breast cancer, and many normal tissues, and we found OR2H1 is expressed in multiple solid epithelial tumors but limited to testis among healthy human tissues. CAR T cells targeting OR2H1-extracellular domain were generated, and OR2H1-specific cytotoxic killing was confirmed, both in vitro and in vivo. Correspondingly, OR2H1-CAR T cells mediate significant therapeutic effects against OR2H1+ NSCLC and high-grade serous ovarian cancer. Interestingly, OR2H1 ablation significantly delays malignant progression of at least NSCLC, but OR2H1 expression is found to be essential for the cytotoxic effects of the OR2H1-CAR T cells. In summary, T cells directed against OR2H1-expressing tumor cells could be a potential therapeutic approach in future for treating OR2H1-expressing cancers. Supported by CA076292, R01CA157664, R01CA124515, R01CA178687, R01CA211913, U01CA232758

OZGUROGLU, MUSTAFA/0000-0002-8417-8628; Senan, Suresh/0000-0003-3995-2204; Cho, Byoung Chul/0000-0002-5562-270X WOS:000535705600013 PubMed ID: 32209338 Background: In the PACIFIC trial, durvalumab significantly improved progression-free and overall survival (PFS/OS) versus placebo, with manageable safety, in unresectable, stage III non-small-cell lung cancer (NSCLC) patients without progression after chemoradiotherapy (CRT). We report exploratory analyses of outcomes by tumour cell (TC) programmed death-ligand 1 (PD-L1) expression. Patients and methods: Patients were randomly assigned (2:1) to intravenous durvalumab 10 mg/kg every 2 weeks or placebo = 25%, = 1%, = 25% (0.41, 0.26-0.65; 17.8 versus 3.7 months), = 1% (0.46, 0.33-0.64; 17.8 versus 5.6 months), = 25% (0.50, 0.30-0.83; NR versus 21.1 months), = 1% (0.59, 0.41-0.83; NR versus 29.6 months), 1%-24% (0.67, 0.41-1.10; 43.3 versus 30.5 months), and unknown (0.60, 0.43-0.84; 44.2 versus 23.5 months), but not

Treatment of locally advanced, unresectable non-small cell lung cancer (NSCLC) has recently been revolutionized by the incorporation of immunotherapy to standard platinum-based concurrent chemoradiation. This review examines the current standard practices and ongoing studies on the management of locally advanced, unresectable NSCLC. Concurrent chemoradiation is the cornerstone of treatment of unresectable, locally advanced NSCLC. However, chemoradiation can be associated with high therapy-related toxicities, and risk of disease relapse remains significantly elevated despite treatment with curative intent. Durvalumab, a PD-L1 inhibitor, was recently approved as consolidation therapy following concurrent chemoradiation; this agent represents a major advancement in treatment of unresectable stage III NSCLC. Several clinical trials are currently underway to evaluate the benefit of different immunotherapy sequencing and other biomarker-driven strategies in this disease setting. Multiple trials are presently ongoing to assess novel immunotherapy and targeted therapy strategies to improve outcomes and decrease treatment-associated toxicities in patients with locally advanced NSCLC.

The immune checkpoint receptor PD-1 on T follicular helper (Tfh) cells promotes Tfh:B cell interactions and appropriate positioning within tissues. Here, we examined the impact of regulation of PD-1 expression by the genomic organizer SATB1 on Tfh cell differentiation. Vaccination of CD4

Outcomes for patients with inoperable locally advanced non-small cell lung cancer (LA-NSCLC) are poor, with a median survival of about 2 years (1) and a 5-year survival of about 10–15% following diagnosis, even among patients with good performance status at presentation (2). Despite these poor outcomes, conventional radiation therapy (RT) with chemotherapy remains the standard of care.

Purpose To evaluate low- vs high-dose plaque brachytherapy for juxtapapillary choroidal melanoma. Design Retrospective interventional case series. Methods Setting: Single institution. Study Population: Forty-seven patients with juxtapapillary choroidal melanoma. Intervention: Iodine-125 plaque brachytherapy. Eyes were divided into apex low-dose (LD) and high-dose (HD) groups (≤ or > median apex dose 84.35 Gy). Main outcome measures were time to distant failure, local failure, death, enucleation, radiation retinopathy, optic neuropathy, and best-corrected visual acuity (BCVA). Results Freedom from distant failure rates were 96% and 95% in apex LD and HD groups at 5 years and 77% and 95% at 10 years, respectively ( P = .84). Freedom from local failure rates were 90% in the apex LD group vs 89% in the HD group at 5 and 10 years ( P = .96). Apex LD and HD groups did not differ for time to death or enucleation. Five- and 10-year freedom from radiation retinopathy and optic neuropathy rates were higher in the apex LD than HD group. Loss of ≥3 BCVA lines, final BCVA 20/40 or better, and final BCVA 20/200 or worse were more favorable in the 5 mm LD compared to HD group. Visual acuity outcomes did not differ between apex LD and HD groups. Conclusions Low-dose iodine-125 plaque brachytherapy (67.5–81 Gy at tumor apex) provides safe and effective tumor control for juxtapapillary choroidal melanoma and may be associated with reduced radiation toxicity. Larger trials are needed to determine the optimal therapeutic dose for juxtapapillary choroidal melanoma.

Purpose/Objective(s) Immune checkpoint inhibitors (ICI) and epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) have shown responses in the management of non-small cell lung cancer (NSCLC) brain metastases (BM). However, optimizing control with stereotactic radiosurgery (SRS) and various systemic therapies in the management of NSCLC BM remains an area of investigation. We evaluated clinical outcomes in NSCLC BM treated with SRS and ICI, EGFR-TKI, ICI and chemotherapy, compared to conventional chemotherapy. Materials/Methods A total of 174 NSCLC BM patients, treated between 2015 and 2019, to a total of 660 intact (non-operative) BM over 239 single-fraction SRS sessions within 3 months of receiving ICI (n = 58; 33%), EGFR-TKI (n = 30; 17%), chemotherapy and ICI (n = 22; 13%) or standard chemotherapy (n = 64; 37%) were identified. Time-to-event analysis was conducted with the Kaplan-Meier method, and outcomes included distant intracranial control (DIC), local control (LC), and overall survival (OS) from SRS. Cox proportional hazards model was utilized for multivariate analysis (MVA) to identify correlations of clinical variables with outcomes. Results Median follow-up from BM diagnosis was 8.9 months (0.26-126.5 months) and 7.3 months from SRS (2.5-17.6 months). No significant differences in age (P = 0.55), gender (P = 0.49), treated gross tumor volume (P = 0.31), presence of systemic metastasis (P = 0.1), SRS dose (P = 0.61), or KPS (0.35) were noted between treatment groups. The 12-month DIC was 35%, 53%, 41%, and 20% (P = 0.02) for ICI, EGFR-TKI, ICI and chemotherapy, and chemotherapy alone groups, respectively. No differences were noted in LC (P = 0.1) and OS (P = 0.5) between treatment groups. Upon MVA, factors found to be significant for improved DIC included treatment with EGFR-TKI therapy compared to conventional chemotherapy (HR 0.4; 95% CI 0.25-0.76; P = 0.04) and treatment with SRS before systemic therapy (HR 0.6; 95% CI 0.3-0.9; P = 0.03). Factors found to be significant for improved LC on MVA included treatment with SRS before (HR 0.4; 95% CI 0.2-0.9; P = 0.03) or concurrent (HR 0.3; 95% CI 0.1-0.6; P = 0.003) compared to following receipt of systemic therapy. Rates of radiation necrosis (RN) did not differ between treatment groups and were 6% (n = 12), 5% (n = 12), 3% (n = 3), 3% (n = 3), for ICI, EGFR-TKI, ICI and chemotherapy, and chemotherapy alone groups, respectively, P = 0.43. In addition, no differences were noted in RN between timing of SRS and receipt of systemic therapy, (P = 0.81). Conclusion In our analysis of NSCLC BM patients treated with single session SRS alongside systemic therapy, we found significant differences in DIC based on receipt of systemic therapy. In addition, treatment with SRS before or concurrent with systemic therapy improved control rates. No differences in RN were noted between treatment groups or by timing of SRS and systemic therapy. Prospective evaluation of the potential synergistic effect between systemic therapy and SRS in NSCLC BM management is warranted. Author Disclosure A.E. Dohm: None. J. Tang: None. M.N. Mills: None. B.A. Perez: Research Grant; BMS.T.J. Robinson: None. B. Creelan: Research Grant; NGenomics Laboratories, Adaptive Biotechnologies Corp. Consultant; Xilio Inc, E.R. Squibb LLC, F. Hoffmann-La Roche AG, AstraZeneca plc, AbbVie, KSQ Therapeutics Inc, GlaxoSmithKline plc, Gilead Sciences Inc, Celgene corp. Speaker's Bureau; AstraZeneca plc, ARIAD Pharmaceuticals, Hoffmann-La Roche AG.J. Gray: None. A.B. Etame: None. M. Vogelbaum: Honoraria; Celgene, Tocagen. Stock Options; Infuseon Therapeutics. Royalty; Infuseon Therapeutics. P. Forsyth: Research Grant; Pfizer, Celgene. Advisory Board; Novocure, BTG, Inovio, AbbVie, Ziopharm, Tocagen, Pfizer. H.M. Yu: Honoraria; UpToDate. Speaker's Bureau; BrainLab. Advisory Board; Novocure, AbbVie. D.E. Oliver: None. K.A. Ahmed: Research Grant; Bristol-Myers Squibb, Genentech.

Purpose/Objective(s) Prescription dose for lung SBRT remains a controversial topic. Based on previous experience, a BED of 100 Gy is necessary to maximize tumor control, though many have advocated higher prescription doses (or dosimetric “hot spots”). To analyze this "imbalanced" problem (few events) and identify which factors affect not only events but the time leading to these events, we hypothesized that advanced actuarial (survival) analysis with machine learning techniques across the entirety of the IGTV/PTV DVH curves in a very large data set would lead to novel findings. Materials/Methods We evaluated 903 courses of lung SBRT, all prescribed to 50 Gy in 5 fractions (BED = 100). There were 37 local failures (crude rate = 4.1%) with median time-to-failure of 587 days (range: 96-1777). Variables analyzed included patient characteristics (gender, age), tumor features (maximum diameter, IGTV/PTV volumes, tumor site, stage), and IGTV/PTV DVH statistics: V1, V2, ... Dmax; D5, D10, ... D95; D0.03cc; mean/median/standard deviation dose; and area under the curve. Mean number of variables per SBRT course was 184 (nearly all dosimetric). Actuarial machine learning methods using Elastic Net with Cox regression (ENC) and Random Survival Forest (RSF) with right censoring were applied in the analysis. ENC is a weighted combination of ridge (penalized Cox with L2 norm) and LASSO (penalized Cox with L1 norm). RSF is an ensemble of survival decision trees constructed by bagging of bootstrapped samples and provides higher predictive power compared to traditional ENC. Categorical variables were represented using one-hot encoding. The data was split 75:25 for training and testing, respectively. Cross-validation was used to mitigate overfitting pitfalls. Variables’ importance was assessed using feature permutation analysis. Results ENC identified IGTV volume as the primary predictor of local failure. Conversely, RSF found PTV volume to be most predictive (with IGTV volume also playing a role). RSF also identified IGTV minimum dose, PTVD15, D0.03cc of the IGTV and PTV, PTV standard deviation, and IGTV D50 and V50 as important features. This combination of features suggests that a minimum BED of 100 Gy is relevant to local control (IGTV minimum dose, IGTV V50), but also that the “hot spot” plays a role (PTVD15, D0.03cc, IGTV D50). We are currently conducting further analysis of these variables to derive dosimetric parameters to incorporate into treatment planning. Conclusion Actuarial machine learning methods such as RSF can identity relevant important variables from highly imbalanced data with few events as in the case of SBRT local failure, while traditional statistical methods like ENC fail to capture such high order features. Our results indicate that in addition to tumor volume, dosimetric variables related to both minimum IGTV dose as well as to maximum IGTV/PTV dose play important roles in SBRT tumor response.

MEM-288 is a dual-transgene armed oncolytic adenovirus being developed for cancer treatment as a standalone agent or in combination with immune checkpoint inhibitors (ICI). MEM-288 is armed with two potent immune agonist transgenes: MEM40, a novel chimeric CD40 ligand (CD40L) designed for stable cell surface expression of CD40L that functions as a potent activator of CD40 expressing dendritic cells (DCs), and the DC and T cell activating cytokine IFNβ. We have evaluated MEM-288 activity in multiple in vivo immunocompetent mouse models to determine impact on systemic antitumor T cell activity after intratumoral virus injection. We were able to readily detect both tumor and immune cell infection and transgene expression following MEM-288 intratumoral administration in mouse tumor models and freshly resected human NSCLC tumors. MEM-288 injection in the syngeneic mouse lung metastatic model 344SQ demonstrated anti-metastatic activity that correlated with a significant enhancement in tumor infiltrating lymphocytes (TILs) and an increase in the systemic antitumor CD8 T cell response. MEM-288 also generated a highly efficacious response against both injected and distant non-injected contralateral tumors in the B16-F10 melanoma model, both as a monotherapy and in combination with ICI. These antitumor and immune responses were only found with MEM-288 as compared to the base adenovirus vector encoding only GFP transgene, indicating the observed effects were highly transgene-dependent. Dissecting the immune stimulatory effects further, we found MEM-288 injection in B16 tumors led to a significant increase in DC activation markers CD80 and CD86 suggesting that DCs may represent a key target of MEM-288 encoded transgenes leading to systemic T cell responses. In support of this hypothesis, we found the MEM-288 CD8 T cell response was completely abolished in BATF3 knockout (KO) mice which lack the cDC1 DC subset (CD8α conventional DC deficient). This suggests that cDC1s are a key mediator of MEM-288 activity. Furthermore, MEM-288 activity was also impaired in both CD40 and type 1 IFN receptor (IFNAR1) KO mice suggesting that both transgenes mediate MEM-288 immune stimulation. In summary, these results demonstrate MEM-288's capacity to induce a potent increase in systemic T cell responses through transgene-mediated stimulation of tumor DCs. This immune stimulatory capacity complements the additional mechanistic features of MEM-288, including enhanced tumor-specific viral replication, oncolysis, and tumor antigen release. MEM-288 is currently being prepared for first-in-human clinical testing in solid tumors as a monotherapy and in combination with ICI. Citation Format: Hong Zheng, Chase D. Powell, Scott Antonia, Mark J. Cantwell, Bradford A. Perez, Amer A. Beg. Defining anti-tumor immune stimulatory mechanisms of MEM-288, a CD40 ligand and IFN-beta dual-transgene armed oncolytic adenovirus [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 697.

Current standard radiotherapy doses have been derived from empiric methods rather than a scientific framework. Subclinical nodal dosing remains relatively uniform across most disease sites, despite heterogeneity in patient and tumor biology. It is now clear that there are subsets of patients who will benefit from genomically-informed radiotherapy planning, and there are increasing efforts toward prescribing radiation dose to match the radiosensitivity of the tumor. By using novel genomic biomarkers to personalize delivery of radiotherapy, there is an opportunity to improve loco-regional control and cure rates. We survey the current landscape of personalized radiation oncology across commonly treated disease sites.

Purpose To evaluate the feasibility of adaptive planning using positron emission tomography–computed tomography (PET-CT) in locally advanced non-small cell lung cancer. Methods and materials Patients with locally advanced non-small cell lung cancer receiving definitive radiation therapy (RT) were eligible. Initial planning PET-CT was performed and a conventional RT plan (2 Gy/fraction to 60 Gy) was designed. A second planning PET-CT was obtained at ~50 Gy. Dose escalation to ~70 Gy for residual fludeoxyglucose-avid disease was pursued at the discretion of the treating oncologists. The primary endpoint was feasibility of adaptive planning using interim PET-CT. Normal tissue dose-volume parameters were calculated for both adaptive and simulated nonadaptive plans. Results From 2012 to 2014, 33 eligible patients were enrolled and underwent planning PET-CT, 3 of which were found to have new distant metastases. Of 30 patients who initiated RT, interim PET-CT was obtained in 29. This showed complete response in 2 patients, partial response/stable disease in 24, and new distant metastases in 3. Selective dose escalation was performed in 17 patients. For those receiving a boost, the median gross tumor volumes pre-RT and at ~50 Gy were 78 mL and 29 mL, respectively ( P = .01). Reasons for no dose escalation were normal tissue constraints (n = 3), poorly defined residual disease (n = 2), acute toxicity (n = 1), and refusal of further therapy (n = 1). Adaptive planning compared with a simulated nonadaptive approach allowed for significant dose reductions to the lungs, heart, and esophagus (all P Conclusions Adaptive planning using PET-CT was feasible and allows for significant dose reductions to normal tissues compared with traditional planning techniques.

Background: Patients with extensive-stage small cell lung cancer (ES-SCLC) often develop brain metastases. There is significant controversy regarding the benefit of prophylactic cranial irradiation (PCI) for patients with ES-SCLC. Our objective is to identify ES-SCLC patients who might be most likely to benefit from PCI. Methods: We retrospectively reviewed 173 patients with ES-SCLC treated between 2010–2015. Of these, 117 patients were initially diagnosed without brain metastases and received systemic chemotherapy. Following exclusion of patients who received PCI and less than 2 cycles of platinum doublet therapy, 93 patients remained. Patient records were reviewed for clinical and radiographic features previously identified as relevant risk factors. Primary outcome was brain metastasis-free survival (BMFS). Kaplan-Meier analysis, log-rank tests and Cox multivariate models were used to compare outcomes. Results: Median follow-up was 10.7 months (range, 3–58 months). Thirty-eight (40.9%) patients developed brain metastases. Three or more metastatic sites was associated with inferior BMFS on univariable (1-year estimate 43.8% vs . 61.3%; P=0.020) and multivariable (MVA) analysis [hazard ratio (HR) 2.33, 95% CI: 1.08–5.01; P=0.03). Conclusions: Our results suggest that extracranial metastatic burden is associated with an increased risk for brain metastases in patients with ES-SCLC. As there is no clear standard regarding delivery of PCI in this patient population, utilizing the number of metastatic disease sites as a clinical indicator may help to improve selection of patients who benefit from PCI.

Background The appropriate follow-up frequency after definitive chemoradiotherapy (CRT) for locally advanced non–small-cell lung cancer patients is unknown. Although surveillance guidelines have been proposed, very few data support current recommendations. Here we analyze relapse events after CRT and investigate whether symptomatic relapses versus those detected by surveillance imaging influences outcomes. Patients and Methods Stage III non–small-cell lung cancer patients treated with CRT at our institution between 2005 and 2014 were retrospectively analyzed. Relapse events were grouped into posttreatment intervals and analyzed with cumulative tables. Time to relapse and overall survival (OS) were compared between patients with relapse detection via symptomatic presentation versus surveillance imaging. Results A total of 211 patients were identified for analysis. The median follow-up was 43 months for patients alive at the time of analysis. The median age was 63 years, and equal proportions had IIIA or IIIB disease. A total of 135 patients (64%) experienced disease relapse, and of these, 74% did so within 12 months. In those who did not experience relapse at ≤ 12 months, 16%, 6%, and 36 months of follow-up, respectively. In patients with relapse, 56% presented symptomatically, which led to inferior median OS compared to those identified by surveillance imaging (23 vs. 36 months; P = .013). Conclusion This study identified that most relapses occur within 1 year of completing CRT, and approximately half of these occur within 6 months. A symptomatic relapse led to inferior OS. More aggressive surveillance imaging may therefore identify asymptomatic relapses that are amenable to earlier salvage therapy.

Introduction We assessed the radiosensitivity of lung metastases on the basis of primary histologic type by using a validated gene signature and model lung metastases for the gnomically adjusted radiation dose (GARD). Methods Tissue samples were identified from our prospective observational protocol. The radiosensitivity index (RSI) 10-gene assay was run on samples and calculated alongside the GARD by using the previously published algorithms. A cohort of 105 patients with 137 lung metastases treated with stereotactic body radiation therapy (SBRT) at our institution was used for clinical correlation. Results A total of 138 unique metastatic lung lesions from our institution’s tissue biorepository were identified for inclusion. There were significant differences in the RSI of lung metastases on the basis of histology. In order of decreasing radioresistance, the median RSIs for the various histologic types of cancer were endometrial adenocarcinoma (0.49), soft-tissue sarcoma (0.47), melanoma (0.44), rectal adenocarcinoma (0.43), renal cell carcinoma (0.33), head and neck squamous cell cancer (0.33), colon adenocarcinoma (0.32), and breast adenocarcinoma (0.29) (p = 0.002). We modeled the GARD for these samples and identified the biologically effective dose necessary to optimize local control. The 12- and 24-month Kaplan-Meier rates of local control for radioresistant versus radiosensitive histologic types from our clinical correlation cohort after lung SBRT were 92%/87% and 100%, respectively (p = 0.02). Conclusions In this analysis, we have noted significant differences in radiosensitivity on the basis of primary histologic type of lung metastases and have modeled the biologically effective dose necessary to optimize local control. This study suggests that primary histologic type may be an additional factor to consider in selection of SBRT dose to the lung and that dose personalization may be feasible.

Background Radiation induced CT changes may be apparent following completion of TRT. We sought to quantify differences in radiation-associated densities on serial CT scans of patients with ES-SCLC treated with TRT alone versus TRT followed by combined IPI and NIVO. Methods Between 2016 and 2018, patients at a single institution with ES-SCLC who achieved stable disease or better following initial treatment with platinum doublet chemotherapy were offered TRT and prescribed a total dose of 30Gy in 10 fractions targeting initially involved thoracic tumor sites. Combined IPI 3mg/kg and NIVO 1mg/kg was administered every 3 weeks for up to 4 doses. We evaluated an irradiated region of interest (ROI) within the lungs and a volume of lung (outside the Planning Target Volume) receiving > 20 Gy. Within the ROI, we calculated the Hounsfield unit (HU) mean for each patient prior to therapy and at subsequent follow-up CT thorax at least 60 days and closest to 120 days after commencing TRT. To quantify CT density change, we measured the difference in HU mean within the irradiated ROI before and after treatment. Results Seventeen patients enrolled on NCT03043599 received TRT followed by combined IPI/NIVO. Two additional patients received the same treatment off protocol. Eleven patients received TRT alone (no IPI/NIVO). The average increase in HU mean within 20Gy irradiated ROI before and after treatment was 9% (max 59%, min -19%) across the study cohort (n = 30). CTCAE grade 3 or higher pulmonary toxicity (N = 8 of 30) was significantly associated with increased CT density change within the ROI (mean 28% vs 2%, p = 0.001). Treatment with TRT and IPI/NIVO (N = 19 of 30) demonstrated a trend towards increased mean CT density change within the ROI compared to patients treated with TRT alone (mean 13% vs. 0%, p = 0.1). Conclusions Quantifying CT density change within irradiated lung parenchyma may offer a novel approach to predict radiation associated pulmonary toxicities. Measuring density changes across patient cohorts receiving TRT with novel systemic therapies may help to identify combined treatment strategies likely to be associated with diminished risk of toxicity. Legal entity responsible for the study The authors. Funding Bristol-Myers Squibb. Disclosure S. Kim: Research grant / Funding (institution): Bristol-Myers Squibb. S.A. Rosenberg: Advisory / Consultancy: Novocure. J.E. Gray: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca; Honoraria (self), Advisory / Consultancy: Celgene; Honoraria (self), Advisory / Consultancy: Takeda; Honoraria (self), Advisory / Consultancy: Janssen; Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Genentech; Honoraria (self), Advisory / Consultancy: Eli Lilly; Honoraria (self), Advisory / Consultancy: Triptych Health Partners. S.J. Antonia: Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy: Merck; Advisory / Consultancy: CBMG; Advisory / Consultancy: Boehringer Ingelheim; Advisory / Consultancy: AstraZeneca/MedImmune; Advisory / Consultancy: Memgen; Advisory / Consultancy: FLX Bio; Advisory / Consultancy: Nektar; Advisory / Consultancy: Venn. B. Perez: Advisory / Consultancy: Bristol-Myers Squibb; Advisory / Consultancy: AstraZeneca. All other authors have declared no conflicts of interest.

The major problem with ventilation distribution calculations using DIR and 4DCT is the motion artifacts in 4DCT. Quite often not all phases would exhibit mushroom motion artifacts. If the ventilation series similarity is sufficiently robust, the ventilation distribution can be calculated using only the artifact-free phases. This study investigated the ventilation similarity among the data derived from different respiration phases. Fifteen lung cancer cases were analyzed. In each case, DIR was performed between the end-expiration phase and all other phases. Ventilation distributions were then calculated using the deformation matrices. The similarity was compared between the series ventilation distributions. The correlation between the majority phases was reasonably good, with average SCC values between 0.28 and 0.70 for the original data and 0.30 and 0.75 after smoothing. The better correlation between the neighboring phases, with average SCC values between 0.55 and 0.70 for the original data, revealed the nonlinear property of the dynamic ventilation. DSC analysis showed the same trend. To reduce the errors if motion artifacts are present, the phases without serious mushroom artifacts may be used. To minimize the effect of the nonlinearity in dynamic ventilation, the calculation phase should be chosen as close to the end-inspiration as possible.