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Purpose We hypothesised that plasticity in signal transduction may be a mechanism of drug resistance and tested this hypothesis in the setting of cetuximab resistance in patients with KRAS/NRAS/BRAFV600 wild-type colorectal cancer (CRC). Methods A multiplex antibody-based platform was used to study simultaneous changes in signal transduction of 55 phospho-proteins in 12 KRAS/NRAS/BRAFV600 wild-type CRC cell lines (6 cetuximab sensitive versus 6 cetuximab resistant) following 1 and 4 h in vitro cetuximab exposure. We validated our results in CRC patient samples (n = 4) using ex vivo exposure to cetuximab in KRAS/NRAS/BRAFV600 cells that were immunomagnetically separated from the serous effusions of patients with known cetuximab resistance. Results Differences in levels of phospho-proteins in cetuximab sensitive and resistant cell lines included reductions in phospho-RPS6 and phospho-PRAS40 in cetuximab sensitive, but not cetuximab resistant cell lines at 1 and 4 h, respectively. In addition, phospho-AKT levels were found to be elevated in 3/4 patient samples following ex vivo incubation with cetuximab for 1 h. We further explored these findings by studying the effects of combinations of cetuximab and two PI3K pathway inhibitors in 3 cetuximab resistant cell lines. The addition of PI3K pathway inhibitors to cetuximab led to a significantly higher reduction in colony formation capacity compared to cetuximab alone. Conclusion Our findings suggest activation of the PI3K pathway as a mechanism of cetuximab resistance in KRAS/NRAS/BRAFV600 wild-type CRC.

Five to ten percent of ER+ metastatic breast cancer (MBC) tumors harbor somatic PTEN mutations. Loss of function of this tumor-suppressor gene defines a highly aggressive, treatment-refractory disease for which new therapies are urgently needed. This Phase I multipart expansion study assessed oral capivasertib with fulvestrant in patients with PTEN-mutant ER+ MBC. Safety and tolerability were assessed by standard methods. Plasma and tumor were collected for NGS and immunohistochemistry analyses of PTEN protein expression. In 31 eligible patients (12 fulvestrant naive; 19 fulvestrant pretreated), the 24-week clinical benefit rate was 17% in fulvestrant-naive and 42% in fulvestrant-pretreated patients, with objective response rate of 8% and 21%, respectively. Non-functional PTEN was centrally confirmed in all cases by NGS or immunohistochemistry. Co­mutations occurred in PIK3CA (32%), with less ESR1 (10% vs 72%) and more TP53 (40% vs 28%) alterations in fulvestrant-naive versus fulvestrant-pretreated patients, respectively. PTEN was clonally dominant in most patients. Treatment-related grade ≥3 adverse events occurred in 32% of patients, most frequently diarrhea and maculopapular rash (both n = 2). In this clinical study, which selectively targeted the aggressive PTEN-mutant ER+ MBC, capivasertib plus fulvestrant was tolerable and clinically active. Phenotypic and genomic differences were apparent between fulvestrant-naive and -pretreated patients.Trial registration number for the study is NCT01226316.

Background: AZD9833 is an oral selective estrogen receptor (ER) antagonist and degrader (SERD) in Phase 2 clinical development for the treatment of ER+ HER2− breast cancer. Here we report data from Parts C and D of the ongoing Phase 1 study (SERENA-1) examining AZD9833 in combination with palbociclib, together with updated data from Parts A and B examining AZD9833 monotherapy. Methods: SERENA-1 (NCT03616587) is an ongoing open-label Phase 1 study of AZD9833 in pre- and post-menopausal women with ER+, HER2− advanced breast cancer who have previously received ≥1 endocrine therapy and ≤2 prior chemotherapies. Prior treatment with fulvestrant and/or CDK4/6 inhibitors was permitted. The primary objective is to determine the safety and tolerability of once daily (QD) AZD9833, with dose-limiting toxicities (DLTs) in the first 28 days defining the maximum tolerated dose. Secondary objectives include anti-tumor response (including circulating tumor [ct] DNA response) and pharmacokinetics. Parts A (escalation) and B (expansion) assess AZD9833 as a monotherapy, and Parts C (escalation) and D (expansion) assess AZD9833 in combination with palbociclib. Results: At a data cut-off of March 24 2020, 17 patients had received either 150 mg or 300 mg AZD9833 in combination with palbociclib, given according to its product labeling. Eighty patients had received AZD9833 monotherapy at doses of 25, 75, 150, 300, and 450 mg QD. In patients treated with AZD9833 and palbociclib, treatment-related adverse events (AEs; experienced by ≥10% of patients) included visual disturbances*, bradycardia*, asthenia, anemia, QTcF prolongation, nausea, neutropenia, decreased white blood cell count, and vomiting (*combined terms). All instances of AZD9833-related bradycardia were Grade 1. One DLT was observed in the 150 mg cohort: CTCAE Grade 2 visual disturbances, which began on Cycle 1 Day 8 and resolved by Cycle 1 Day 9 following dose interruption. The patient restarted treatment on Cycle 1 Day 15 at 75 mg and continued this dose until data cut-off. No causally related AEs led to discontinuation of AZD9833. The tolerability of AZD9833 with palbociclib was consistent with the observed tolerability profile of AZD9833 monotherapy, and the known tolerability profile of palbociclib. Pharmacokinetic analysis showed similar AZD9833 exposure for monotherapy and palbociclib combination therapy. Similarly, palbociclib exposure was comparable with simulations using a published population pharmacokinetic model. In Part A, ESR1 hotspot mutations were detected in ctDNA at baseline in 26/56 (46%) patients; 13/26 (50%) of these patients achieved a partial response or stable disease at 24 weeks, including 5/10 (50%) with a Y537S ESR1 mutation. Further, in patients with ESR1 mutations and samples available for longitudinal ctDNA analysis, 17/20 (85%) exhibited a reduction or loss of mutant ESR1 on treatment with AZD9833. Efficacy data to be presented include objective response rate and clinical benefit rate at 24 weeks. Of note, unconfirmed partial responses have been observed in Part C after the data cut-off for this abstract. Conclusions: AZD9833 continues to show an encouraging efficacy and dose-dependent safety profile as a monotherapy or in combination with palbociclib. A Phase 2 study comparing the efficacy and safety of three doses of AZD9833 versus fulvestrant (NCT04214288), and a Phase 2 pre-surgical ‘window of opportunity’ study (EUDRA-CT; 2019-003706-2) are ongoing. Citation Format: Richard Baird, Mafalda Oliveira, Eva Maria Ciruelos Gil, Manish R Patel, Begoña Bermejo de las Heras, Manuel Ruiz-Borrego, Javier García-Corbacho, Anne Armstrong, Udai Banerji, Chris Twelves, Valentina Boni, Jason Incorvati, Peter Kabos, Adam L Cohen, Bruno de Paula, Marta Capelán Rodríguez, Judy S Wang, Christina Hernando, Alejandro Falcón Gonzalez, Ivan Victoria Ruiz, Julia Lai-Kwon, Anosheh Afghani, Christos Vaklavas, Tim Brier, Steven Fox, Bistra Kirova, Teresa Klinowska, Chris Leach, Justin PO Lindemann, Richard Mather, Rhiannon Maudsley, Christopher J Morrow, Nitharsan Sathiyayogan, Andy Sykes, Li Zhang, Erika Hamilton. Updated data from SERENA-1: A Phase 1 dose escalation and expansion study of the next generation oral SERD AZD9833 as a monotherapy and in combination with palbociclib, in women with ER-positive, HER2-negative advanced breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS11-05.

Background KRAS is mutated in ∼90% of pancreatic ductal adenocarcinomas, ∼35% of colorectal cancers and ∼20% of non-small-cell lung cancers. There has been recent progress in targeting G12CKRAS specifically, but therapeutic options for other mutant forms of KRAS are limited, largely because the complexity of downstream signaling and feedback mechanisms mean that targeting individual pathway components is ineffective. Design The protein kinases RAF and SRC are validated therapeutic targets in KRAS-mutant pancreatic ductal adenocarcinomas, colorectal cancers and non-small-cell lung cancers and we show that both must be inhibited to block growth of these cancers. We describe CCT3833, a new drug that inhibits both RAF and SRC, which may be effective in KRAS-mutant cancers. Results We show that CCT3833 inhibits RAF and SRC in KRAS-mutant tumors in vitro and in vivo, and that it inhibits tumor growth at well-tolerated doses in mice. CCT3833 has been evaluated in a phase I clinical trial (NCT02437227) and we report here that it significantly prolongs progression-free survival of a patient with a G12VKRAS spindle cell sarcoma who did not respond to a multikinase inhibitor and therefore had limited treatment options. Conclusions New drug CCT3833 elicits significant preclinical therapeutic efficacy in KRAS-mutant colorectal, lung and pancreatic tumor xenografts, demonstrating a treatment option for several areas of unmet clinical need. Based on these preclinical data and the phase I clinical unconfirmed response in a patient with KRAS-mutant spindle cell sarcoma, CCT3833 requires further evaluation in patients with other KRAS-mutant cancers., Highlights • We synthesized new drug, CCT3833, that inhibits both RAF and SRC, and so may be effective in KRAS-mutant cancers. • CCT3833 inhibits both signaling pathways in vitro and in vivo, inhibits tumor growth and leads to regressions in mice. • CCT3833 significantly prolonged progression-free survival of a patient with a G12VKRAS spindle cell sarcoma. • CCT3833 is a potential treatment option for several areas of unmet clinical need.

Background CH5126766 (also known as VS-6766, and previously named R05126766), a novel MEK-pan-RAF inhibitor, has shown antitumour activity across various solid tumours; however, its initial development was limited by toxicity. We aimed to investigate the safety and toxicity profile of intermittent dosing schedules of CH5126766, and the antitumour activity of this drug in patients with solid tumours and multiple myeloma harbouring RAS-RAF-MEK pathway mutations. Methods We did a single-centre, open-label, phase 1 dose-escalation and basket dose-expansion study at the Royal Marsden National Health Service Foundation Trust (London, UK). Patients were eligible for the study if they were aged 18 years or older, had cancers that were refractory to conventional treatment or for which no conventional therapy existed, and if they had a WHO performance status score of 0 or 1. For the dose-escalation phase, eligible patients had histologically or cytologically confirmed advanced or inetastatic solid tumours. For the basket doseexpansion phase, eligible patients had advanced or metastatic solid tumours or multiple myeloma harbouring RAS-RAF-MEK pathway mutations. During the dose-escalation phase, we evaluated three intermittent oral schedules (28-day cycles) in patients with solid tumours: (1) 4.0 mg or 3.2 mg CH5126766 three times per week; (2) 4.0 mg CH5126766 twice per week; and (3) toxicity-guided dose interruption schedule, in which treatment at the recommended phase 2 dose (4.0 mg CH5126766 twice per week) was de-escalated to 3 weeks on followed by 1 week off if patients had prespecified toxic effects (grade 2 or worse diarrhoea, rash, or creatinine phosphokinase elevation). In the basket dose-expansion phase, we evaluated antitumour activity at the recommended phase 2 dose, determined from the dose-escalation phase, in biomarker-selected patients. The primary endpoints were the recommended phase 2 dose at which no more than one out of six patients had a treatment-related dose-limiting toxicity, and the safety and toxicity profile of each dosing schedule. The key secondary endpoint was investigator-assessed response rate in the dose-expansion phase. Patients who received at least one dose of the study drug were evaluable for safety and patients who received one cycle of the study drug and underwent baseline disease assessment were evaluable for response. This trial is registered with ClinicalTrials.gov, NCT02407509. Findings Between June 5,2013, and Jan 10,2019,58 eligible patients were enrolled to the study: 29 patients with solid tumours were included in the dose-escalation cohort and 29 patients with solid tumours or multiple myeloma were included in the basket dose-expansion cohort (12 non-small-cell lung cancer, five gynaecological malignancy, four colorectal cancer, one melanoma, and seven multiple myeloma). Median follow-up at the time of data cutoff was 2.3 months (IQR 1.6-3.5). Dose-limiting toxicities included grade 3 bilateral retinal pigment epithelial detachment in one patient who received 4.0 mg CH5126766 three times per week, and grade 3 rash (in two patients) and grade 3 creatinine phosphokinase elevation (in one patient) in those who received 3.2 mg CH5126766 three times per week. 4.0 mg CH5126766 twice per week (on Monday and Thursday or Tuesday and Friday) was established as the recommended phase 2 dose. The most common grade 3-4 treatment-related adverse events were rash (11 [19%] patients), creatinine phosphokinase elevation (six [11%1), hypoalbuminaemia (six [11%]), and fatigue (four [7%1). Five (9%) patients had serious treatment-related adverse events. There were no treatment-related deaths. Eight (14%) of 57 patients died during the trial due to disease progression. Seven (27% [95% CI 11.6-47.8]) of 26 response-evaluable patients in the basket expansion achieved objective responses. Interpretation To our knowledge, this is the first study to show that highly intermittent schedules of a RAF-MEK inhibitor has antitumour activity across various cancers with RAF-RAS-MEK pathway mutations, and that this inhibitor is tolerable. CH5126766 used as a monotherapy and in combination regimens warrants further evaluation. Copyright (C) 2020 Elsevier Ltd. All rights reserved.

Preclinical studies have demonstrated synergy between PARP and PI3K/AKT pathway inhibitors in BRCA1 and BRCA2 (BRCA1/2)–deficient and BRCA1/2-proficient tumors. We conducted an investigator-initiated phase I trial utilizing a prospective intrapatient dose- escalation design to assess two schedules of capivasertib (AKT inhibitor) with olaparib (PARP inhibitor) in 64 patients with advanced solid tumors. Dose expansions enrolled germline BRCA1/2-mutant tumors, or BRCA1/2 wild-type cancers harboring somatic DNA damage response (DDR) or PI3K–AKT pathway alterations. The combination was well tolerated. Recommended phase II doses for the two schedules were: olaparib 300 mg twice a day with either capivasertib 400 mg twice a day 4 days on, 3 days off, or capivasertib 640 mg twice a day 2 days on, 5 days off. Pharmacokinetics were dose proportional. Pharmacodynamic studies confirmed phosphorylated (p) GSK3β suppression, increased pERK, and decreased BRCA1 expression. Twenty-five (44.6%) of 56 evaluable patients achieved clinical benefit (RECIST complete response/partial response or stable disease ≥ 4 months), including patients with tumors harboring germline BRCA1/2 mutations and BRCA1/2 wild-type cancers with or without DDR and PI3K–AKT pathway alterations. Significance: In the first trial to combine PARP and AKT inhibitors, a prospective intrapatient dose- escalation design demonstrated safety, tolerability, and pharmacokinetic–pharmacodynamic activity and assessed predictive biomarkers of response/resistance. Antitumor activity was observed in patients harboring tumors with germline BRCA1/2 mutations and BRCA1/2 wild-type cancers with or without somatic DDR and/or PI3K–AKT pathway alterations. This article is highlighted in the In This Issue feature, p. 1426

PURPOSE Preclinical studies demonstrated that ATR inhibition can exploit synthetic lethality (eg, in cancer cells with impaired compensatory DNA damage responses through ATM loss) as monotherapy and combined with DNA-damaging drugs such as carboplatin. PATIENTS AND METHODS This phase I trial assessed the ATR inhibitor M6620 (VX-970) as monotherapy (once or twice weekly) and combined with carboplatin (carboplatin on day 1 and M6620 on days 2 and 9 in 21-day cycles). Primary objectives were safety, tolerability, and maximum tolerated dose; secondary objectives included pharmacokinetics and antitumor activity; exploratory objectives included pharmacodynamics in timed paired tumor biopsies. RESULTS Forty patients were enrolled; 17 received M6620 monotherapy, which was safe and well tolerated. The recommended phase II dose (RP2D) for once- or twice-weekly administration was 240 mg/m2. A patient with metastatic colorectal cancer harboring molecular aberrations, including ATM loss and an ARID1A mutation, achieved RECISTv1.1 complete response and maintained this response, with a progression-free survival of 29 months at last assessment. Twenty-three patients received M6620 with carboplatin, with mechanism-based hematologic toxicities at higher doses, requiring dose delays and reductions. The RP2D for combination therapy was M6620 90 mg/m2 with carboplatin AUC5. A patient with advanced germline BRCA1 ovarian cancer achieved RECISTv1.1 partial response and Gynecologic Cancer Intergroup CA125 response despite being platinum refractory and PARP inhibitor resistant. An additional 15 patients had RECISTv1.1 stable disease as best response. Pharmacokinetics were dose proportional and exceeded preclinical efficacious levels. Pharmacodynamic studies demonstrated substantial inhibition of phosphorylation of CHK1, the downstream ATR substrate. CONCLUSION To our knowledge, this report is the first of an ATR inhibitor as monotherapy and combined with carboplatin. M6620 was well tolerated, with target engagement and preliminary antitumor responses observed.

Purpose: Drug-induced interstitial lung disease (DILD) is a rare, but potentially fatal toxicity. Clinical and radiological features of DILD in the early experimental setting are poorly described. Patients and Methods: A total of 2,499 consecutive patients with advanced cancer on phase I clinical trials were included. DILD was identified by a dedicated radiologist and investigators, categorized per internationally recognized radiological patterns, and graded per Common Terminology Criteria for Adverse Events (CTCAE) and the Royal Marsden Hospital (RMH) DILD score. Clinical and radiological features of DILD were analyzed. Results: Sixty patients overall (2.4%) developed DILD. Median time to onset of DILD was 63 days (range, 14–336 days). A total of 45% of patients who developed DILD were clinically asymptomatic. Incidence was highest in patients receiving drug conjugates (7.4%), followed by inhibitors of the PI3K/AKT/mTOR pathway (3.9%). The most common pattern seen was hypersensitivity pneumonitis (33.3%), followed by nonspecific interstitial pneumonia (30%), and cryptogenic organizing pneumonia (26.7%). A higher DILD score [OR, 1.47, 95% confidence interval (CI), 1.19–1.81; P < 0.001] and the pattern of DILD (OR, 5.83 for acute interstitial pneumonia; 95% CI, 0.38–90.26; P = 0.002) were significantly associated with a higher CTCAE grading. The only predictive factor for an improvement in DILD was an interruption of treatment (OR, 0.05; 95% CI, 0.01–0.35; P = 0.01). Conclusions: DILD in early-phase clinical trials is a toxicity of variable onset, with diverse clinical and radiological findings. Radiological findings precede clinical symptoms. The extent of the affected lung parenchyma, scored by the RMH DILD score, correlates with clinical presentation. Most events are low grade, and improve with treatment interruption, which should be considered early.

Purpose:The activating mutation AKT1E17K occurs in approximately 7% of estrogen receptor–positive (ER+) metastatic breast cancer (MBC). We report, from a multipart, first-in-human, phase I study (NCT01226316), tolerability and activity of capivasertib, an oral AKT inhibitor, as monotherapy or combined with fulvestrant in expansion cohorts of patients with AKT1E17K-mutant ER+ MBC.Patients and Methods:Patients with an AKT1E17K mutation, detected by local (next-generation sequencing) or central (plasma-based BEAMing) testing, received capivasertib 480 mg twice daily, 4 days on, 3 days off, weekly or 400 mg twice daily combined with fulvestrant at the labeled dose. Study endpoints included safety, objective response rate (ORR; RECIST v1.1), progression-free survival (PFS), and clinical benefit rate at 24 weeks (CBR24). Biomarker analyses were conducted in the combination cohort.Results:From October 2013 to August 2018, 63 heavily pretreated patients received capivasertib (20 monotherapy, 43 combination). ORR was 20% with monotherapy, and within the combination cohort was 36% in fulvestrant-pretreated and 20% in fulvestrant-naïve patients, although the latter group may have had more aggressive disease at baseline. AKT1E17K mutations were detectable in plasma by BEAMing (95%, 41/43), droplet digital PCR (80%, 33/41), and next-generation sequencing (76%, 31/41). A ≥50% decrease in AKT1E17K at cycle 2 day 1 was associated with improved PFS. Combination therapy appeared more tolerable than monotherapy [most frequent grade ≥3 adverse events: rash (9% vs. 20%), hyperglycemia (5% vs. 30%), diarrhea (5% vs. 10%)].Conclusions:Capivasertib demonstrated clinically meaningful activity in heavily pretreated patients with AKT1E17K-mutant ER+ MBC, including those with prior disease progression on fulvestrant. Tolerability and activity appeared improved by the combination.

Through the use of an unbiased, genome-scale CRISPR modifier screen, we identified NF1 suppression as a mechanism of resistance to EGFR inhibition in NRAS/KRAS/BRAFV600-wild-type colorectal cancer cells. Reduced NF1 expression permitted sustained signaling through the MAPK pathway to promote cell proliferation in the presence of EGFR inhibition. Targeting of MEK in combination with EGFR inhibition leads to synergistic antiproliferative activity. Human KRAS/NRAS/BRAFV600-wild-type colorectal cancer cell lines with NF1 mutations displayed reduced NF1 mRNA or protein expression and were resistant to EGFR blockade by gefitinib or cetuximab. Cooccurring loss-of-function mutations in PTEN were associated with resistance to dual EGFR/MEK inhibition but cotreatment with a PI3K inhibitor further suppressed proliferation. Loss of NF1 may be a useful biomarker to identify patients that are less likely to benefit from single-agent anti-EGFR therapy in colorectal cancer and may direct potential combination strategies. Implications: This study suggests that further clinical validation of NF1 status as predictor of response to anti-EGFR targeting antibodies in patients with colorectal cancer with KRAS/NRAS/BRAFV600-wild-type tumors is warranted.

Drug resistance mediated by clonal evolution is arguably the biggest problem in cancer therapy today. However, evolving resistance to one drug may come at a cost of decreased fecundity or increased sensitivity to another drug. These evolutionary trade-offs can be exploited using ‘evolutionary steering’ to control the tumour population and delay resistance. However, recapitulating cancer evolutionary dynamics experimentally remains challenging. Here, we present an approach for evolutionary steering based on a combination of single-cell barcoding, large populations of 108–109 cells grown without re-plating, longitudinal non-destructive monitoring of cancer clones, and mathematical modelling of tumour evolution. We demonstrate evolutionary steering in a lung cancer model, showing that it shifts the clonal composition of the tumour in our favour, leading to collateral sensitivity and proliferative costs. Genomic profiling revealed some of the mechanisms that drive evolved sensitivity. This approach allows modelling evolutionary steering strategies that can potentially control treatment resistance., Evolutionary steering uses therapies to control tumour evolution by exploiting trade-offs. Here, using a barcoding approach applied to large cell populations, the authors explore evolutionary steering in lung cancer cells treated with EGFR inhibitors.

Folate receptor α (FRα) came into focus as an anticancer target many decades after the successful development of drugs targeting intracellular folate metabolism, such as methotrexate and pemetrexed. Binding to FRα is one of several methods by which folate is taken up by cells; however, this receptor is an attractive anticancer drug target owing to the overexpression of FRα in a range of solid tumours, including ovarian, lung and breast cancers. Furthermore, using FRα to better localize effective anticancer therapies to their target tumours using platforms such as antibody–drug conjugates, small-molecule drug conjugates, radioimmunoconjugates and, more recently, chimeric antigen receptor T cells could further improve the outcomes of patients with FRα-overexpressing cancers. FRα can also be harnessed for predictive biomarker research. Moreover, imaging FRα radiologically or in real time during surgery can lead to improved functional imaging and surgical outcomes, respectively. In this Review, we describe the current status of research into FRα in cancer, including data from several late-phase clinical trials involving FRα-targeted therapies, and the use of new technologies to develop FRα-targeted agents with improved therapeutic indices. Cancer cells, like non-malignant cells, are dependent on folate uptake for growth. However, cancer cells are much more reliant on folate receptors (FRs) and particularly FRα for folate uptake than non-malignant cells. In this Review, the authors describe the available data on the role of FRα as a biomarker and as a target of imaging probes, and of targeted therapies in patients with solid tumours.

Background: Loss of function in the tumor suppressor gene, PTEN, activates PI3K/AKT signaling, driving tumor growth. Somatic mutations in PTEN occur in 5-10% of estrogen-receptor-positive (ER+) breast cancer (BC), and PTEN loss/inactivation is associated with an aggressive BC phenotype and poor outcome. Capivasertib, a pan-AKT kinase inhibitor, has shown antitumor activity in solid tumors. In ER+ BC, suppression of PI3K/AKT signaling results in a compensatory increase in ER-dependent transcription, potentially limiting the efficacy of AKT inhibitors when given as monotherapy. We therefore investigated concurrent inhibition of AKT and ER with combination therapy of capivasertib and fulvestrant in PTEN-mutant ER+ metastatic BC (MBC). Methods: In an expansion cohort (part F) of a Phase I study (NCT01226316), oral capivasertib 400 mg twice daily, 4 days on 3 days off, and fulvestrant at labeled dose, was administered to ER+ MBC patients (pts) with tumors harboring a deleterious PTEN alteration (identified in tissue/plasma by local next-generation sequencing [NGS], with central NGS and immunohistochemistry [IHC] performed retrospectively). Pts were enrolled in fulvestrant-naïve (FN) or fulvestrant-resistant (FR) cohorts (max 24 pts/cohort). Key objectives included safety and efficacy based on 24-week clinical benefit rate (CBR). Results: At data cut-off, 31 pts (12 FN; 19 FR) received treatment. Median number of prior metastatic regimens was 7. FN pts had higher rates of visceral disease (100%) and prior chemotherapy receipt (median 4 [range 0-8]) than FR pts (84%; median 2 [1-7]), respectively]. CBR and median progression-free survival (PFS) were 17% and 2.6 months in FN pts, and 37% and 4.1 months in FR pts, respectively (Table). Twenty-four patients (77%) had PTEN mutations and 7 (23%) had PTEN gene deletions determined by local NGS. Central plasma NGS confirmed 79% (19/24) of the PTEN mutations, and IHC confirmed complete loss of the PTENprotein in 85% (22/26) of cases. Treatment-related grade ≥3 adverse events (AEs) occurred in 32%, most frequently diarrhea and maculopapular rash (both n=2 pts). Treatment-related AEs resulted in dose reduction in 2 pts. Table. Clinical efficacyFN, n=12FR, n=19ORR, % (95% CI)8 (0.2, 39)21 (6, 46)CBR, % (95% CI)17 (2, 48)37 (16, 62)Confirmed response, n (%)1 (8)4 (21)Stable disease ≥24 weeks, n (%)2 (17)3 (16)Median PFS, months (95% CI)2.6 (1.2–4.2)4.1 (1.5–6.7)Median duration of response, months (95% CI)5.5 (NC–NC)6.9 (1.4–NC)Data cut-off was 21 March 2019. Median time from last fulvestrant administration to study entry in FR pts (n=19) was 13.8 months (range 0.7–28.2). CBR was defined as confirmed responders and those with stable disease ≥24 weeks. NC, not calculable (because of limited pt numbers); ORR, objective response rate Conclusions: Capivasertib plus fulvestrant is clinically active in heavily pretreated PTEN-mutated ER+ MBC, including in pts with prior resistance to fulvestrant. Efficacy appeared marginally better in FR than FN pts, possibly due to enrichment of pts with more aggressive disease in the FN cohort. Further analyses of the relationship between genomic features, such as concurrent mutations with drug activity, will be reported. Citation Format: Lillian M Smyth, Gerald Batist, Funda Meric-Bernstam, Peter Kabos, Iben Spanggaard, Ana Lluch, Alison Schram, Andrea Varga, Andrea Wong, Helen Ambrose, Alan Barnicle, T. Hedley Carr, Elza C de Bruin, Carolina Salinas-Souza, Andrew Foxley, Joana Hauser, Justin PO Lindemann, Rhiannon Maudsley, Robert McEwen, Michele Moschetta, Martine Roudier, Gaia Schiavon, Pedram Razavi, Udai Banerji, Sarat Chandarlapaty, José Baselga, David M Hyman. Capivasertib (AZD5363) in combination with fulvestrant in PTEN-mutant ER+ metastatic breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-19-05.

Background Activation of the PI3K/AKT/mTOR pathway through loss of phosphatase and tensin homolog (PTEN) occurs in approximately 50% of patients with metastatic castration-resistant prostate cancer (mCRPC). Recent evidence suggests that combined inhibition of the androgen receptor (AR) and AKT may be beneficial in mCRPC with PTEN loss. Patients and methods mCRPC patients who previously failed abiraterone and/or enzalutamide, received escalating doses of AZD5363 (capivasertib) starting at 320 mg twice daily (b.i.d.) given 4 days on and 3 days off, in combination with enzalutamide 160 mg daily. The co-primary endpoints were safety/tolerability and determining the maximum tolerated dose and recommended phase II dose; pharmacokinetics, antitumour activity, and exploratory biomarker analysis were also evaluated. Results Sixteen patients were enrolled, 15 received study treatment and 13 were assessable for dose-limiting toxicities (DLTs). Patients were treated at 320, 400, and 480 mg b.i.d. dose levels of capivasertib. The recommended phase II dose identified for capivasertib was 400 mg b.i.d. with 1/6 patients experiencing a DLT (maculopapular rash) at this level. The most common grade ≥3 adverse events were hyperglycemia (26.7%) and rash (20%). Concomitant administration of enzalutamide significantly decreased plasma exposure of capivasertib, though this did not appear to impact pharmacodynamics. Three patients met the criteria for response (defined as prostate-specific antigen decline ≥50%, circulating tumour cell conversion, and/or radiological response). Responses were seen in patients with PTEN loss or activating mutations in AKT, low or absent AR-V7 expression, as well as those with an increase in phosphorylated extracellular signal-regulated kinase (pERK) in post-exposure samples. Conclusions The combination of capivasertib and enzalutamide is tolerable and has antitumour activity, with all responding patients harbouring aberrations in the PI3K/AKT/mTOR pathway. Clinical Trial Number NCT02525068, Highlights • Preclinical data suggest that inhibition of both the AR and PI3K/AKT/mTOR signalling has synergistic activity in PTEN loss prostate cancer models. • Here we present a phase I clinical trial of enzalutamide combined with the AKT inhibitor capivasertib in patients with mCRPC and show that this regimen is safe and tolerable. • This combination has antitumour activity with all responding patients harbouring aberrations in the PI3K/AKT/mTOR pathway.

Introduction Immune checkpoint inhibitors (ICIs) are increasingly a standard of care for many cancers; these agents can result in immune-related adverse events (irAEs) including fever, which is common but can rarely be associated with systemic immune activation (SIA or acquired HLH). Methods All consecutive patients receiving ICIs in the Drug Development Unit of the Royal Marsden Hospital between May 2014 and November 2019 were retrospectively reviewed. Patients with fever ≥ 38°C or chills/rigors (without fever) ≤ 6 weeks of commencing ICIs were identified for clinical data collection. Results Three patients met diagnostic criteria for SIA/HLH with median time to onset of symptoms of 10 days. We describe the clinical evolution, treatment used, and outcomes for these patients. High-dose steroids are used first-line with other treatments, such as tocilizumab, immunoglobulin and therapeutic plasmapheresis can be considered for steroid-refractory SIA/HLH. Conclusion SIA/HLH post ICI is a rare but a potentially fatal irAE that presents with fever and a constellation of nonspecific symptoms. Early recognition and timely treatment are key to improving outcomes.

HSP90 is involved in stability and function of cancer-related proteins. This study was conducted to define the MTD, safety, pharmacokinetics, pharmacodynamics, and preliminary antitumor efficacy of TAS-116, a novel class, orally available, highly selective inhibitor of HSP90. Patients with advanced solid tumors received TAS-116 orally once daily (QD, step 1) or every other day (QOD, step 2) in 21-day cycles. Each step comprised a dose escalation phase to determine MTD and an expansion phase at the MTD. In the dose escalation phase, an accelerated dose-titration design and a “3+3” design were used. Sixty-one patients were enrolled in Japan and the United Kingdom. MTD was determined to be 107.5 mg/m2/day for QD, and 210.7 mg/m2/day for QOD. In the expansion phase of step 1, TAS-116 was administered 5 days on/2 days off per week (QD × 5). The most common treatment-related adverse events included gastrointestinal disorders, creatinine increases, AST increases, ALT increases, and eye disorders. Eye disorders have been reported with HSP90 inhibitors; however, those observed with TAS-116 in the expansion phases were limited to grade 1. The systemic exposure of TAS-116 increased dose-proportionally with QD and QOD regimens. Two patients with non–small cell lung cancer and one patient with gastrointestinal stromal tumor (GIST) achieved a confirmed partial response. TAS-116 had an acceptable safety profile with some antitumor activity, supporting further development of this HSP90 inhibitor. This is a result from a first-in-human study, in which the HSP90 inhibitor TAS-116 demonstrated preliminary antitumor efficacy in patients with advanced solid tumors, including those with heavily pretreated GIST.

Aim: We explore HER3 expression in lung adenocarcinoma (adeno-NSCLC) and identify potential mechanisms of HER3 expression. Materials & methods: Tumor samples from 45 patients with adeno-NSCLC were analyzed. HER3 and HER2 expression were identified using immunohistochemistry and bioinformatic interrogation of The Cancer Genome Atlas (TCGA). Results: HER3 was highly expressed in 42.2% of cases. ERBB3 copy number did not account for HER3 overexpression. Bioinformatic analysis of TCGA demonstrated that MEK activity score (a surrogate of functional signaling) did not correlate with HER3 ligands. ERBB3 RNA expression levels were significantly correlated with MEK activity after adjusting for EGFR expression. Conclusion: HER3 expression is common and is a potential therapeutic target by virtue of frequent overexpression and functional downstream signaling., Tweetable abstract HER3 expression is common in adeno-NSCLC and is a potential therapeutic target by virtue of frequent overexpression and functional downstream signaling.

Background Malignant pleural mesothelioma (MPM) is traditionally characterized by local destructive spread of the pleura and surrounding tissues. Patient outcomes in MPM with distant metastatic dissemination are lacking. Methods In this retrospective study, we reviewed a cohort of 164 MPM patients referred to a Phase I trials unit, aiming to describe identified metastatic sites, and correlate with clinical outcomes. Results 67% of patients were diagnosed with distant metastatic disease with a high incidence of bone (19%), visceral (14%), contralateral lung (35%) and peritoneal metastases (22%). Peritoneal metastases were more likely in epithelioid versus biphasic/ sarcomatoid MPM (p = 0.015). Overall survival was 23.8 months with no statistical difference in survival between those with distant metastases and those without. Conclusions This report highlights the frequency of distant metastases and encourages further radiological investigations in the presence of symptoms. In particular, given the relatively high incidence of bone metastases, bone imaging should be considered in advanced MPM clinical workflow and trial protocols. The presence of distant metastases does not appear to have prognostic implications under existing treatment paradigms. This cohort of MPM patients gives an indication of patterns of metastatic spread that are likely to become prevalent as prognosis improves with emerging treatment paradigms.

Purpose: AT13148 is an oral AGC kinase inhibitor, which potently inhibits ROCK and AKT kinases. In preclinical models, AT13148 has been shown to have antimetastatic and antiproliferative activity. Patients and Methods: The trial followed a rolling six design during dose escalation. An intrapatient dose escalation arm to evaluate tolerability and a biopsy cohort to study pharmacodynamic effects were later added. AT13148 was administered orally three days a week (Mon–Wed–Fri) in 28-day cycles. Pharmacokinetic profiles were assessed using mass spectrometry and pharmacodynamic studies included quantifying p-GSK3β levels in platelet-rich plasma (PRP) and p-cofilin and p-MLC2 levels in tumor biopsies. Results: Fifty-one patients were treated on study. The safety of 5–300 mg of AT13148 was studied. Further, the doses of 120–180–240 mg were studied in an intrapatient dose escalation cohort. The dose-limiting toxicities included hypotension (300 mg), pneumonitis, and elevated liver enzymes (240 mg), and skin rash (180 mg). The most common side effects were fatigue, nausea, headaches, and hypotension. On the basis of tolerability, 180 mg was considered the maximally tolerated dose. At 180 mg, mean Cmax and AUC were 400 nmol/L and 13,000 nmol/L/hour, respectively. At 180 mg, ≥50% reduction of p-cofilin was observed in 3 of 8 posttreatment biopsies. Conclusions: AT13148 was the first dual potent ROCK-AKT inhibitor to be investigated for the treatment of solid tumors. The narrow therapeutic index and the pharmacokinetic profile led to recommend not developing this compound further. There are significant lessons learned in designing and testing agents that simultaneously inhibit multiple kinases including AGC kinases in cancer.

BackgroundHER-3 has a role in pathogenesis and development of resistance to targeted therapies in non-small cell lung cancer (NSCLC). MethodsWe analysed tumour samples from 45 patients with adenocarcinoma of the lung. HER-3 and HER-2 expression was identified using immunohistochemistry as well as bioinformatic interrogation of The Cancer Genome Atlas (TGCA). ResultsHER-3 was highly expressed in 42.2% of cases and observed more frequently than HER-2 overexpression. ERBB3 copy number alone did not account for HER-3 overexpression. Bioinformatic analysis of TCGA demonstrated that MEK activity score (a score of downstream pathway activity and surrogate of functional HER-3 signalling) did not correlate with HER-3 ligands. EGFR pathway signalling was predominant with a significantly positive correlation of EGFR and AREG expression with MEK activity score. In the ERBB3 expressed group, ERBB3 RNA expression levels were significantly correlated with MEK activity score. ERBB3 expression level remained highly positively correlated with MEK activity after adjusting for EGFR expression. ConclusionHER-3 expression is common and it is not associated with gene amplification nor is it ligand dependent. HER-3 is an alternative pathway to EGFR activating MEK. HER-3 is a potential therapeutic target in NSCLC by virtue of frequent overexpression and functional downstream signalling.

Background The incidence and clinical significance of electrolyte abnormalities (EAs) in phase I clinical trials are unknown. The objective of this study is to evaluate the incidence and severity of EAs, graded according to CTCAE, v4.03, to identify variables associated with EAs and their prognostic significance in a phase I population. Methods A retrospective chart review was performed of 1088 cases in 82 phase I clinical trials consecutively treated from 2011 to 2015 at the Drug Development Unit of the Royal Marsden Hospital. Cox regression analysis was performed to examine the relationship between overall survival (OS) and baseline characteristics, treating the occurrence of grade III/IV EAs as a time-varying covariate. Results The most common emergent EAs (all grades) were as follows: hyponatraemia 62%, hypokalaemia 40%, hypophosphataemia 32%, hypomagnesaemia 17% and hypocalcaemia 12%. Grade III/IV EAs occurred in 19% of cases. Grade III/IV EAs occurred during the dose-limiting toxicity window in 8.46% of cases. Diarrhoea was associated with hypomagnesaemia at all grades (p, Highlights • Patients who develop grade III/IV electrolyte abnormalities have poorer overall survival. • Hyponatraemia is linked to higher risk of developing other electrolyte abnormalities. • Hypoalbuminaemia is linked to higher risk of developing electrolyte abnormalities.

Highlights • Summary of a protocol for a phase I study combining the ATR inhibitor and palliative radiotherapy. • Study design is discussed. • Study aims and objectives, brief eligibility criteria, DLT criteria and dose escalation is discussed. • Brief summary of translational research to be carried out., PATRIOT is a phase I study of the ATR inhibitor, AZD6738, as monotherapy, and in combination with palliative radiotherapy. Here, we describe the protocol for this study, which opened in 2014 and is currently recruiting and comprises dose escalation of both drug and radiotherapy, and expansion cohorts.

PURPOSE: AZD5363 is a potent pan-AKT inhibitor originally formulated as a capsule; a tablet was developed for patient convenience and manufacturing ease. This study assessed the PK comparability of both formulations (Part A) and the effect of food (Part B) on the PK/safety of the tablet.METHODS: Adults with advanced solid tumours received AZD5363 480 mg bid in a partially fasted state by tablet (Week 1) and capsule (Week 2) in a '4-days-on/3-days-off' schedule (Part A). PK parameters were evaluated using pre-defined 90% CIs for AUCτ and Cmax ratios of 0.75-1.33 to assess comparability. In Part B, AZD5363 tablet was given to a new cohort of patients under the same conditions as Part A, except on the morning of PK assessment days, when it was administered after an overnight fast (Week 1) and standard meal (Week 2).RESULTS: In evaluable patients (N = 11), the geometric least-squares mean ratios (tablet:capsule) for AUCτ and Cmax were 0.90 (0.77-1.06) and 1.02 (0.86-1.20), respectively, demonstrating comparable PK in the partially fasted state. Tablet and capsule safety data were also comparable. Tablet PK profiles indicated later tmax and lower Cmax after food versus overnight fast. Fed and fasted AUCτ and Cmax ratios were 0.89 (0.76-1.05) and 0.67 (0.55-0.82), respectively (N = 9). The safety/tolerability profile of the tablet was comparable between fed and fasted states.CONCLUSIONS: PK and safety/tolerability of AZD5363 tablet and capsule were comparable. Food did not affect the bioavailability of AZD5363, but reduced the absorption rate without discernibly affecting safety/tolerability.

Although the neutrophil-lymphocyte ratio (NLR) is prognostic in many oncological settings, its significance in the immunotherapy era is unknown. Mechanistically, PD-1/PD-L1 inhibitors may alter NLR. We sought to characterise NLR kinetics in patients with advanced solid tumours treated with PD-1/PD-L1 inhibitors.Electronic records of patients treated with PD-1/PD-L1 inhibitors on phase I trials across three sites were reviewed. A high NLR (hNLR) was predefined as5. Univariate logistic regression models were used for toxicity, response analyses and Cox models for overall survival (OS) and progression-free survival analyses. Landmark analyses were performed (cycle two, three). Longitudinal analysis of NLR was performed utilising a mixed effect regression model.The median OS for patients with hNLR was 8.5 months and 19.4 for patients with low NLR, (hazard ratio [HR] = 1.85, 95% confidence interval [CI] 1.15-2.96, p = 0.01). On landmark analysis, hNLR was significantly associated with inferior OS at all time points with a similar magnitude of effect over time (p 0.05). On multivariate analysis, NLR was associated with OS (HR 1.06, 95% CI 1.01-1.11, p = 0.01). NLR did not correlate with increased immune toxicity. Longitudinally, NLR correlated with response: NLR decreased by 0.09 (95% CI: -0.15 to -0.02; p = 0.01) per month in responders compared with non-responders.hNLR at baseline and during treatment is adversely prognostic in patients with advanced malignancies receiving PD-1/PD-L1 blockade. Importantly, NLR reduced over time in responders to immunotherapy. Taken together, these data suggest that baseline and longitudinal NLR may have utility as a unique biomarker to aid clinical decision-making in patients receiving immunotherapy.

SummaryKRAS mutations drive a wide variety of cancers. Drugs targeting the protein product of KRASG12C mutations are currently being evaluated show preliminary efficacy in clinical trials. A clinical trial of VS-6766, a dual RAF–MEK inhibitor, has reported early single agent activity in non-G12C mutated KRAS driven cancers.

Aims Despite improved understanding of effector T-cell trafficking into the central nervous system, initial trials with anti-PD1/PD-L1 immune checkpoint inhibitors (ICIs) have failed to meet their primary endpoints. PTEN loss of function is frequent in GBM and has been correlated with not only poor overall prognosis, but also impaired antitumour responses, including reduced T cell infiltration into tumour and reduced efficacy of ICIs. Ipatasertib is a novel, potent, selective, small-molecule inhibitor of Akt. We have shown that Ipatasertib efficiently depletes FOXP3+ regulatory T cells from the tumour microenvironment (TME) resulting in increased infiltration of effector T cells in solid tumours (Lopez 2020, AACR). We hypothesize that the use of AKT inhibition in PTEN glioblastomas may deplete the TME of suppressive immune cells, and render malignant brain tumours more responsive to ICIs. We present updated data for the combination of Ipat+ATZ in patients with glioblastoma. Method Patients with relapsed WHO grade IV GBM with stable neurological symptoms ≥5 days prior to enrolment, requiring The Ice-CAP A2 cohort assessed safety, pharmacodynamic, and preliminary clinical activity of Ipat (200mg or 400mg OD) + ATZ (1200mg Q3W) in pts with potentially resectable relapsed WHO Grade IV GBM. Pts had a 14-21-day run-in phase of Ipat then surgical tumour resection. Combination Ipat+ATZ commenced post surgery. Patients who declined surgery or who were deemed high risk for surgery proceeded directly to combination. Patients in the expansion cohort B3 commenced directly on Ipat+ATZ at the RP2D of 400mg Ipat with ATZ. Results 16 evaluable recurrent GBM pts were enrolled across two cohorts. Median age 56 yrs (25-71 yrs). Median ECOG PS 1. Median lines of prior therapy 1 (range 1-4). 10 pts had PTEN loss by IHC (H No DLTs, treatment-related (TR) serious adverse events (AEs), or immune-related AEs were observed. Most common TR AEs were G1 diarrhoea (44%), mucositis (17%), rash (28%). Clinical benefit rate (CR, PR and SD> 6 cycles) at clinical cutoff date (23/02/21) in patients with PTEN aberration was 30% (3/10). A 58-year-old man with PTEN loss had MRI at Cycle 5 showing worsening enhancement suggestive of disease progression. Resection of the lesion showed intense lymphocyte infiltration and pathological CR. He is currently on Cycle 22 with no evidence of disease. Two other patients with PTEN loss with radiological stable disease per RANO criteria remain well on study for >6 cycles. Conclusion Combination Ipat+ATZ appears safe and tolerable in GBM pts, with 400mg Ipatasertib OD + 1200mg ATZ Q3W declared as RP2D. Early efficacy signals were detected with PTEN loss being a promising predictive biomarker for response to combination. An expansion cohort enriched with pts with PTEN loss is ongoing.

IntroductionEarly phase cancer clinical trials have become increasingly complicated in terms of patient selection and trial procedures—this is reflected in the increasing length of participant information sheets (PIS). Informed consent for early phase clinical trials has been contentious due to the potential ethical issues associated with performing experimental research on a terminally ill population which has exhausted standard treatment options. Empirical studies have demonstrated significant gaps in patient understanding regarding the nature and intent of these trials. This study aims to test whether enhanced informed consent for patient education can improve patient scores on a validated questionnaire testing clinical trial comprehension.Methods and analysisThis is a randomised controlled trial that will allocate patients who are eligible to participate in one of four investigator-initiated clinical trials at the Royal Marsden Drug Development Unit to either a standard arm or an experimental arm, stratified by age and educational level. The standard arm will involve the full length trial PIS, followed by electronic or paper administration of the Quality of Informed Consent Questionnaire Parts A and B (QuIC-A and QuIC-B). The experimental arm will involve the full length trial PIS, exposure to a two-page study aid and 10 online educational videos, followed by administration of the QuIC-A and QuIC-B. The primary endpoint will be the difference (using a one-sided two-sample t-test) in the QuIC-A score, which measures objective understanding, between the standard and experimental arm. Accrual target is at least 17 patients per arm to detect an 8 point difference (80% power, alpha 0.05).Ethics and disseminationEthics approval was granted by the National Health Service Health Research Authority on 15 June 2020—IRAS Project ID 277065, Protocol Number CCR5165, REC Reference 20/EE/0155. Results will be disseminated via publication in a relevant journal.Trial registration numberNCT04407676; Pre-results.

Purpose of study: CHK1 and WEE1 are critical determinants of the G2/M cell cycle checkpoint. The G2/M checkpoint is crucial to enable DNA repair caused by endogenous and exogenous stress. We hypothesised that simultaneous inhibition of CHK1 and WEE1 would cause cell death in TP53 mutated cell lines because of the associated replication stress due to an abrogated G1/S checkpoint. Experimental procedures: The potentiation index of the combination of SRA737 and adavosertib was calculated in six cancer cell lines harbouring TP53 mutations (OVCAR3, COV505, BT20, MDA-MB-436 and CAPAN1, MIAPaCa2) using Cell Titre Blue assays. Cell death and DNA damage was quantified using c-PARP, p-CHK1 Ser345 and gamma H2AX using western blot analysis. In-vivo studies evaluated the efficacy of vehicle control, SRA737, adavosertib and the combination in OVCAR3 and MDA-MB-436 xenograft models. We further explored the mechanisms of DNA damage repair caused by the single agents and the combination using two functional fluorescent multiplex DNA repair assay platforms in OVCAR3 and MDA-MB-436 cells; Exy-SPOT (base excision repair/nucleotide excision repair) and Next-SPOT (double strand break repair). Results: The potentiation index of the addition of SRA737 to adavosertib were 19, 8.6, 8.8, 9.7, 27.2 and 5.7 for COV504, OVCAR3, BT20, MDA-MB-436, CAPAN1 and MIAPaCa2 respectively. The combination of both drugs at single agent GI50 concentrations caused increase in c-PARP, p-CHK1 Ser345 and gamma H2AX in all cell lines studied. We chose to explore the combination in the TP53 mutated OVCAR3 and the TP53 and BRCA1 mutated MDA-MB-436 cell lines. In the OVCAR3 xenograft model, the combination of SRA737 and adavosertib caused tumour regressions and tumour volumes were significantly smaller than controls, p Conclusions: The combination of SRA737 and adavosertib caused cell death in TP53 mutated cell lines. There were differences in the DNA damage repair mechanisms in across cell lines and the combination showed significant activity in the xenograft models studied. The combination of SRA737 and adavosertib warrants further evaluation for the treatment of selected TP53 mutated cancers. Citation Format: Adam Stewart, Lisa Pickard, Albert E. Hallsworth, Sylvie Sauvaigo, Giovanna Muggiolu, Florence Raynaud, UDAI BANERJI. A study of combinatorial growth inhibition, cell death and DNA damage repair caused by CHK1 inhibitor SRA737 and WEE1 inhibitor adavosertib in TP53 mutated cell lines [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 1010.

Background: Hyperactivation of the PI3K/AKT pathway correlates with impaired antitumour response, including reduced T cell infiltration into tumour and reduced efficacy of immune checkpoint inhibitors (ICIs). PTEN loss of function, often observed in GBM, may contribute to refractoriness of ICIs in this disease. Methods: The Ice-CAP A2 cohort assessed safety, pharmacodynamic, and preliminary clinical activity of Ipa (200mg or 400mg OD) + A (1200mg Q3W) in pts with potentially resectable relapsed WHO Grade IV GBM. Key inclusion criteria were stable neurological symptoms ≥5 days prior to enrolment, steroid requirement 12wks, both on 400mg Ipa. A 58-year-old man with PTEN loss had MRI at Cycle 5 showing worsening enhancement suggestive of disease progression. Resection of the lesion showed intense lymphocyte infiltration and pathological CR. He is currently on Cycle 18 with no evidence of disease. Conclusion: Combination Ipa+A appears safe and tolerable in GBM pts, with 400mg Ipa OD + 1200mg A Q3W declared as RP2D. PTEN loss may be a promising predictive biomarker for response to combination. An expansion cohort enriched with pts with PTEN loss is ongoing. Cytokine and FACS data will be presented at AACR Table 1.Clinical Benefit Rate of glioblastoma patients stratified according to PTEN aberrationsPTEN statusnBest responseClinical Benefit RatePTEN loss on IHC (H12 wks, ongoingb3 PDPTEN aberration on NGS but PTEN protein expression pending11 PDcPTEN loss of heterozygozity on PCR11 PDWild type PTEN on NGS or IHC (H≥30)33 PDLegend: IHC = immunohistochemistry; NGS = next generation sequencing; PCR = polymerase chain reaction;pCR = pathologic complete response; SD = stable disease; PD = progressive diseaseaExceptional responder with PTEN H=5 on IHC and splice site 75_79+2delGACCTGT on NGSb PTENY68*; c PTENQ298* Citation Format: Crescens Tiu, Andrea Biondo, Liam C. Welsh, Timothy L. Jones, Anna Zachariou, Toby Prout, Alison J. Turner, Robert Daly, Igor Vivanco, Christina Yap, Ben Jenkins, Mateus Crespo, Ruth Riisnaes, Suzanne Carreira, Bora Gurel, Nina Tunariu, Anna Minchom, Udai Banerji, Johann S. de Bono, Juanita S. Lopez. Results of the glioblastoma multiforme (GBM) cohort of phase 1 trial Ice-CAP (NCT03673787): Preliminary evidence of antitumour activity of Ipatasertib (Ipa) and Atezolizumab (A) in patients (pts) with PTEN loss [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 CT120.

Activation of the PI3K/mTOR pathway has been shown to be correlated with resistance to chemotherapy in ovarian cancer. We aimed to investigate the effects of combining inhibition of mTORC1 and 2 using the mTOR kinase inhibitor vistusertib (AZD2014) with paclitaxel in in vitro and in vivo ovarian cancer models. The combination of vistusertib and paclitaxel on cell growth was additive in a majority of cell lines in the panel (n = 12) studied. A cisplatin- resistant model (A2780Cis) was studied in vitro and in vivo. We demonstrated inhibition of mTORC1 and mTORC2 by vistusertib and the combination by showing reduction in p-S6 and p-AKT levels, respectively. In the A2780CisR xenograft model compared to control, there was a significant reduction in tumor volumes (p = 0.03) caused by the combination and not paclitaxel or vistusertib alone. In vivo, we observed a significant increase in apoptosis (cleaved PARP measured by immunohistochemistry; p = 0.0003). Decreases in phospholipid and bioenergetic metabolites were studied using magnetic resonance spectroscopy and significant changes in phosphocholine (p = 0.01), and ATP (p = 0.04) were seen in tumors treated with the combination when compared to vehicle-control. Based on this data, a clinical trial evaluating the combination of paclitaxel and vistusertib has been initiated (NCT02193633). Interestingly, treatment of ovarian cancer patients with paclitaxel caused an increase in p-AKT levels in platelet-rich plasma and it was possible to abrogate this increase with the co-treatment with vistusertib in 4/5 patients: we believe this combination will benefit patients with ovarian cancer.

Purpose AKT1 E17K mutations are oncogenic and occur in many cancers at a low prevalence. We performed a multihistology basket study of AZD5363, an ATP-competitive pan-AKT kinase inhibitor, to determine the preliminary activity of AKT inhibition in AKT-mutant cancers. Patients and Methods Fifty-eight patients with advanced solid tumors were treated. The primary end point was safety; secondary end points were progression-free survival (PFS) and response according to Response Evaluation Criteria in Solid Tumors (RECIST). Tumor biopsies and plasma cell-free DNA (cfDNA) were collected in the majority of patients to identify predictive biomarkers of response. Results In patients with AKT1 E17K–mutant tumors (n = 52) and a median of five lines of prior therapy, the median PFS was 5.5 months (95% CI, 2.9 to 6.9 months), 6.6 months (95% CI, 1.5 to 8.3 months), and 4.2 months (95% CI, 2.1 to 12.8 months) in patients with estrogen receptor–positive breast, gynecologic, and other solid tumors, respectively. In an exploratory biomarker analysis, imbalance of the AKT1 E17K–mutant allele, most frequently caused by copy-neutral loss-of-heterozygosity targeting the wild-type allele, was associated with longer PFS (hazard ratio [HR], 0.41; P = .04), as was the presence of coincident PI3K pathway hotspot mutations (HR, 0.21; P = .045). Persistent declines in AKT1 E17K in cfDNA were associated with improved PFS (HR, 0.18; P = .004) and response ( P = .025). Responses were not restricted to patients with detectable AKT1 E17K in pretreatment cfDNA. The most common grade ≥ 3 adverse events were hyperglycemia (24%), diarrhea (17%), and rash (15.5%). Conclusion This study provides the first clinical data that AKT1 E17K is a therapeutic target in human cancer. The genomic context of the AKT1 E17K mutation further conditioned response to AZD5363.

Drug resistance to conventional anticancer therapies is almost inevitable in patients with advanced ovarian cancer (AOC), limiting their available treatment options. Novel phase I trial therapies within a dedicated drug development unit may represent a viable alternative; however, there is currently little evidence for patient outcomes in such patients. To address this, we undertook a retrospective review of patients with AOC allocated to phase I trials in the Drug Development Unit at Royal Marsden Hospital (RMH) between June 1998 and October 2010. A total of 200 AOC patients with progressive disease were allocated to ≥1 trial each, with a total of 281 allocations. Of these, 135 (68%) patients commenced ≥1 trial (mean 1.4 [1-8]), totaling 216 allocated trials; 65 (32%) patients did not start due to deterioration resulting from rapidly progressive disease (63 patients) or patient choice (2 patients). Response Evaluation Criteria in Solid Tumours (RECIST) complete/partial responses (CR/PR) were observed in 43 (20%) of those starting trials, including those on poly(ADP-ribose) polymerase (PARP) inhibitors (18/79 [23%]), antiangiogenics (9/65 [14%]) and chemotherapy combinations (14/43 [33%]). Factors associated with CR/PR included: fewer prior treatments, platinum-sensitive disease, CR/PR with prior therapy, (the United States-based) Eastern Cooperative Oncology Group (ECOG) performance status score, fewer metastatic sites, higher albumin and haemoglobin levels, lower white cell counts and baseline CA125 levels, germline BRCA1/2 mutations and better RMH Prognostic Score. Mean survival was 32° months for patients who achieved CR/PR. Treatments were generally well tolerated. Most patients with AOC (134/200 [67%]) received ≥1 subsequent line of therapy after phase I trials. Our data suggest that phase I trial referrals should be considered earlier in the AOC treatment pathway and before the onset of rapid disease progression particularly with the emergence of promising novel agents in the era of precision medicine.

Purpose To evaluate MK-8242 in patients with wild-type TP53 advanced solid tumors. Patients and Methods MK-8242 was administered orally twice a day on days 1 to 7 in 21-day cycles. The recommended phase II dose (RP2D) was determined on the basis of safety, tolerability, pharmacokinetics (PK), and by mRNA expression of the p53 target gene pleckstrin homology-like domain, family A, member 3 ( PHLDA3). Other objectives were to characterize the PK/pharmacodynamic (PD) relationship, correlate biomarkers with response, and assess tumor response. Results Forty-seven patients received MK-8242 across eight doses that ranged from 60 to 500 mg. Initially, six patients developed dose-limiting toxicities (DLTs): grade (G) 2 nausea at 120 mg; G3 fatigue at 250 mg; G2 nausea and G4 thrombocytopenia at 350 mg; and G3 vomiting and G3 diarrhea at 500 mg. DLT criteria were revised to permit management of GI toxicities. Dosing was resumed at 400 mg, and four additional DLTs were observed: G4 neutropenia and G4 thrombocytopenia at 400 mg and G4 thrombocytopenia (two patients) at 500 mg. Other drug-related G3 and G4 events included anemia, leukopenia, pancytopenia, nausea, hyperbilirubinemia, hypophosphatemia, and anorexia. On the basis of safety, tolerability, PK, and PD, the RP2D was established at 400 mg (15 evaluable patients experienced two DLTs). PK for 400 mg (day 7) showed Cmax 3.07 μM, Tmax 3.0 hours, t1/2 (half-life) 6.6 hours, CL/F (apparent clearance) 28.9 L/h, and Vd/F (apparent volume) 274 L. Blood PHLDA3 mRNA expression correlated with drug exposure ( R2 = 0.68; P < .001). In 41 patients with postbaseline scans, three patients with liposarcoma achieved a partial response (at 250, 400, and 500 mg), 31 showed stable disease, and eight had progressive disease. In total, 27 patients with liposarcoma had a median progression-free survival of 237 days. Conclusion At the RP2D of 400 mg twice a day, MK-8242 activated the p53 pathway with an acceptable safety and tolerability profile. The observed clinical activity (partial response and prolonged progression-free survival) provides an impetus for further study of HDM2 inhibitors in liposarcoma.

Background: SYD985 is a HER2-targeting antibody-drug conjugate (ADC) based on trastuzumab and a cleavable linker-duocarmycin (vc-seco-DUBA) payload. Following proteolytic cleavage the synthetic duocarmycin prodrug is activated, binds to the minor groove of DNA, and subsequently causes irreversible DNA-alkylation. SYD985 has demonstrated unprecedented anti-tumor activity in preclinical breast cancer models with high (HER2 3+) or moderate/low expression of HER2 (HER2 2+ and HER2 1+). Clinical data of patients with HER2-positive and HER2-negative breast cancer treated with SYD985 in an ongoing first-in-human phase I trial (NCT02277717) in patients with locally advanced or metastatic solid tumors are presented. Trial design: Main inclusion criteria are ECOG performance status 0-1, left ventricular ejection fraction ≥ 55%, and adequate organ function. Patients are treated with SYD985 every three weeks until tumor progression or unacceptable toxicity. Thirty nine patients, including 26 breast cancer patients, were enrolled in the dose-escalation part and treated with doses varying from 0.3 mg/kg to 2.4 mg/kg SYD985. Patients enrolling in the first expanded cohort will be treated with 1.2 mg/kg SYD985. In this cohort a total of 48 patients with HER2-positive breast cancer (IHC 3+ or ISH positive) will be enrolled from May 2016 onwards. HER2 status was determined locally in the dose-escalation part but will be done centrally in the expanded cohort part of the trial. Tumor evaluation (RECIST 1.1) is performed every 6 weeks. Results: Enrolled breast cancer patients were heavily pretreated with a median of 7 systemic therapies. All patients with HER2-positive breast cancer were previously treated with trastuzumab and ado-trastuzumab emtansine (T-DM1). As of 16 May 2016, tumor evaluation data were available for 19 of the 26 enrolled breast cancer patients. In total, 8 partial responses were observed of which 6 were confirmed by a second CT-scan. The number of cycles administered ranged from 1 to 11. Ten of the 26 patients are still on treatment. Best overall response HER2 statusN EvaluablePRSDPDORR All dosesORR Doses ≥1.2 mg/kgHER2-positive (all T-DM1 pretreated)1458136%42%HER2-negative (IHC 1+/2+ and ISH neg)531160%75%Overall1989242%50% One dose-limiting toxicity occurred at 2.4 mg/kg SYD985, i.e. pneumonitis (grade 5). Overall, SYD985 is well tolerated up to doses of 1.8 mg/kg every 3 weeks. The most frequently reported drug-related AEs were conjunctivitis, stomatitis, fatigue, and decreased appetite. The majority of drug-related AEs were of mild or moderate intensity. Conclusion: SYD985 shows promising efficacy in both HER2-positive and HER2-negative metastatic breast cancer patients with an acceptable safety profile. SYD985 may offer a new targeted treatment option for patients who have become refractory to the available HER2-targeting therapies, and potentially for breast cancer patients who are not indicated for HER2-targeting therapies. Updated data, including additional results of up to 48 HER2-positive breast cancer patients, will be presented during the meeting. Citation Format: Aftimos PG, van Herpen CM, Mommers EC, Koper NP, Goedings P, Oesterholt M, Awada A, Desar IM, Lim J, Dean E, Rolfo C, Macpherson I, Banerji U. SYD985, a novel anti-HER2 ADC, shows promising activity in patients with HER2-positive and HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-02.

KRAS mutation is a key driver of pancreatic cancer and PI3K pathway activity is an additional requirement for Kras-induced tumorigenesis. Clinical trials of PI3K pathway inhibitors in pancreatic cancer have shown limited responses. Understanding the molecular basis for this lack of efficacy may direct future treatment strategies with emerging PI3K inhibitors. We sought new therapeutic approaches that synergize with PI3K inhibitors through pooled CRISPR modifier genetic screening and a drug combination screen. ERBB family receptor tyrosine kinase signaling and mTOR signaling were key modifiers of sensitivity to alpelisib and pictilisib. Inhibition of the ERBB family or mTOR was synergistic with PI3K inhibition in spheroid, stromal cocultures. Near-complete loss of ribosomal S6 phosphorylation was associated with synergy. Genetic alterations in the ERBB–PI3K signaling axis were associated with decreased survival of patients with pancreatic cancer. Suppression of the PI3K/mTOR axis is potentiated by dual PI3K and ERBB family or mTOR inhibition. Surprisingly, despite the presence of oncogenic KRAS, thought to bestow independence from receptor tyrosine kinase signaling, inhibition of the ERBB family blocks downstream pathway activation and synergizes with PI3K inhibitors. Further exploration of these therapeutic combinations is warranted for the treatment of pancreatic cancer.

Background Trastuzumab duocarmazine is a novel HER2-targeting antibody-drug conjugate comprised of trastuzumab covalently bound to a linker drug containing duocarmycin. Preclinical studies showed promising antitumour activity in various models. In this first-in-human study, we assessed the safety and activity of trastuzumab duocarmazine in patients with advanced solid tumours.Methods We did a phase 1 dose-escalation and dose-expansion study. The dose-escalation cohort comprised patients aged 18 years or older enrolled from three academic hospitals in Belgium, the Netherlands, and the UK with locally advanced or metastatic solid tumours with variable HER2 status who were refractory to standard cancer treatment. A separate cohort of patients were enrolled to the dose-expansion phase from 15 hospitals in Belgium, the Netherlands, Spain, and the UK. Dose-expansion cohorts included patients aged 18 years or older with breast, gastric, urothelial, or endometrial cancer with at least HER2 immunohistochemistry 1+ expression and measurable disease according to Response Evaluation Criteria in Solid Tumors (RECIST). Trastuzumab duocarmazine was administered intravenously on day 1 of each 3-week cycle. In the dose-escalation phase, trastuzumab duocarmazine was given at doses of 0.3 mg/kg to 2.4 mg/kg (3 + 3 design) until disease progression or unacceptable toxicity. The primary endpoint of the dose-escalation phase was to assess safety and ascertain the recommended phase 2 dose, which would be the dose used in the dose-expansion phase. The primary endpoint of the dose-expansion phase was the proportion of patients achieving an objective response (complete response or partial response), as assessed by the investigator using RECIST version 1.1. This ongoing study is registered with ClinicalTrials.gov, number NCT02277717, and is fully recruited.Findings Between Oct 30, 2014, and April 2, 2018, 39 patients were enrolled and treated in the dose-escalation phase and 146 patients were enrolled and treated in the dose-expansion phase. One dose-limiting toxic effect (death from pneumonitis) occurred at the highest administered dose (2.4 mg/kg) in the dose-escalation phase. One further death occurred in the dose-escalation phase (1.5 mg/kg cohort) due to disease progression, which was attributed to general physical health decline. Grade 3-4 treatment-related adverse events reported more than once in the dose-escalation phase were keratitis (n=3) and fatigue (n=2). Based on all available data, the recommended phase 2 dose was set at 1.2 mg/kg. In the dose-expansion phase, treatment-related serious adverse events were reported in 16 (11%) of 146 patients, most commonly infusion-related reactions (two [1%]) and dyspnoea (two [1%]). The most common treatment-related adverse events (grades 1-4) were fatigue (48 [33%] of 146 patients), conjunctivitis (45 [31%]), and dry eye (45 [31%]). Most patients (104 [71%] of 146) had at least one ocular adverse event, with grade 3 events reported in ten (7%) of 146 patients. No patients died from treatment-related adverse events and four patients died due to disease progression, which were attributed to hepatic failure (n=1), upper gastrointestinal haemorrhage (n=1), neurological decompensation (n=1), and renal failure (n=1). In the breast cancer dose-expansion cohorts, 16 (33%, 95% CI 20.4-48.4) of 48 assessable patients with HER2-positive breast cancer achieved an objective response (all partial responses) according to RECIST. Nine (28%, 95% CI 13.8-46.8) of 32 patients with HER2-low, hormone receptor-positive breast cancer and six (40%, 16.3-67.6) of 15 patients with HER2-low, hormone receptor-negative breast cancer achieved an objective response (all partial responses). Partial responses were also observed in one (6%, 95% CI 0.2-30.2) of 16 patients with gastric cancer, four (25%, 7.3-52.4) of 16 patients with urothelial cancer, and five (39%, 13.9-68.4) of 13 patients with endometrial cancer.Interpretation Trastuzumab duocarmazine shows notable clinical activity in heavily pretreated patients with HER2-expressing metastatic cancer, including HER2-positive trastuzumab emtansine-resistant and HER2-low breast cancer, with a manageable safety profile. Further investigation of trastuzumab duocarmazine for HER2-positive breast cancer is ongoing and trials for HER2-low breast cancer and other HER2-expressing cancers are in preparation. Copyright (C) 2019 Elsevier Ltd. All rights reserved.

Drug resistance mediated by clonal evolution is arguably the biggest problem in cancer therapy today. However, evolving resistance to one drug may come at a cost of decreased growth rate or increased sensitivity to another drug due to evolutionary trade-offs. This weakness can be exploited in the clinic using an approach called ‘evolutionary herding’ that aims at controlling the tumour cell population to delay or prevent resistance. However, recapitulating cancer evolutionary dynamics experimentally remains challenging. Here we present a novel approach for evolutionary herding based on a combination of single-cell barcoding, very large populations of 108–109cells grown without re-plating, longitudinal non-destructive monitoring of cancer clones, and mathematical modelling of tumour evolution. We demonstrate evolutionary herding in non-small cell lung cancer, showing that herding allows shifting the clonal composition of a tumour in our favour, leading to collateral drug sensitivity and proliferative fitness costs. Through genomic analysis and single-cell sequencing, we were also able to determine the mechanisms that drive such evolved sensitivity. Our approach allows modelling evolutionary trade-offs experimentally to test patient-specific evolutionary herding strategies that can potentially be translated into the clinic to control treatment resistance.

Background Molecular aberrations in cancer may represent therapeutic targets, and, if arising from the germline, may impact further cancer risk management in patients and their blood relatives. Annually, 600–700 patients are referred for consideration of experimental drug trials in the Drug Development Unit (DDU) in our institution. A proportion of patients may merit germline genetic testing because of suspicious personal/family history or findings of tumour-based testing. We aimed to assess the impact of different multidisciplinary interventions on family history taking and referral rates from DDU to Cancer Genetics Unit (CGU). Methods Over 42 months, three interventions were undertaken at different intervals: (1) embedding a genetics provider in the DDU review clinic, (2) ‘traffic light’ system flagging cancers with a heritable component and (3) virtual multidisciplinary meeting (MDM). Comparative analyses between intervals were undertaken, including referral rates to CGU, investigations and patient outcomes. Family history taking in a sample of 20 patients managed in each interval was assessed by a retrospective chart review. Results Frequency of family history taking and referral to CGU, increased with each intervention, particularly, the virtual MDM (40% vs 85%). Referral rates increased over the study period, from 0.1 referral/week (5/year, 0.36% total referrals) to 1.2/week (projected 63/year, 3.81%). Forty-four (52%) patients referred required germline testing; in three of whom, variants were identified. Non-attendance rates were low (6, 7%). Conclusion Patients in the DDU are unique, with long cancer histories and often short estimated life expectancy. Multidisciplinary working between CGU and DDU facilitates germline testing of those patients who may otherwise miss the opportunity.

Four PARP inhibitors have been approved by the FDA as cancer therapeutics, yet there are several clinical settings where no strong rationale exists to inform clinicians on which to choose in terms of clinical effectiveness and toxicity. The four drugs have largely similar PARP family inhibition profiles, but several differences at the molecular and clinical level have been reported that remain poorly understood. We previously hypothesized that PARP inhibitors could have an inherent capacity to inhibit kinases off-target. Here, we characterise the off-target kinase landscape of four FDA-approved PARP drugs. We demonstrate that all four PARP inhibitors have a unique polypharmacological profile across the kinome. Niraparib and rucaparib inhibit DYRK1s, CDK16 and PIM3 at clinically achievable submicromolar concentrations. These represent the most potently inhibited off-targets of PARP inhibitors identified to date and should be investigated further to clarify their potential implications for efficacy and safety in the clinic, including use of PARP inhibitors in combination with other agents, including immunotherapy.

TPS3145 Background: Response to existing chemotherapeutics (chemo) can be limited by exposure, itself limited by systemic toxicity. Interstitial fluid pressure can impede transport of drugs with, in some cases

Malignant pleural mesothelioma (MPM) is traditionally characterized by local destructive spread of the pleura and surrounding tissues. Patient outcomes in MPM with distant metastatic dissemination are lacking.In this retrospective study, we reviewed a cohort of 164 MPM patients referred to a Phase I trials unit, aiming to describe identified metastatic sites, and correlate with clinical outcomes.67% of patients were diagnosed with distant metastatic disease with a high incidence of bone (19%), visceral (14%), contralateral lung (35%) and peritoneal metastases (22%). Peritoneal metastases were more likely in epithelioid versus biphasic/ sarcomatoid MPM (p = 0.015). Overall survival was 23.8 months with no statistical difference in survival between those with distant metastases and those without.This report highlights the frequency of distant metastases and encourages further radiological investigations in the presence of symptoms. In particular, given the relatively high incidence of bone metastases, bone imaging should be considered in advanced MPM clinical workflow and trial protocols. The presence of distant metastases does not appear to have prognostic implications under existing treatment paradigms. This cohort of MPM patients gives an indication of patterns of metastatic spread that are likely to become prevalent as prognosis improves with emerging treatment paradigms.

Early-phase cancer clinical trials are becoming increasingly accessible for patients with advanced cancer who have exhausted standard treatment options and later phase trial options. Many of these trials mandate research tissue biopsies. Research biopsies have been perceived as ethically fraught due to the perception of potential coercion of vulnerable human subjects. We performed an audit of two years of practice to assess the safety of ultrasound (US)-guided research biopsies, and to look at the yield of a simultaneous tumour next-generation sequencing (NGS) and immunohistochemistry (IHC) molecular characterisation programme. We show that in our institution, US-guided research biopsies were safe, produced adequate tumour content and in a selected subset who underwent in-house NGS sequencing, showed a high rate of actionable mutations with 30% having a Tier 1 variant. Nevertheless, these research biopsies may only provide direct benefit for a minority of patients and we conclude with a reflection on the importance of obtaining truly informed consent.