Society for Immunotherapy of Cancer (SITC) recommendations on intratumoral immunotherapy clinical trials (IICT): from premalignant to metastatic disease.

BACKGROUND: Intratumorally delivered immunotherapies have the potential to favorably alter the local tumor microenvironment and may stimulate systemic host immunity, offering an alternative or adjunct to other local and systemic treatments. Despite their potential, these therapies have had limited success in late-phase trials for advanced cancer resulting in few formal approvals. The Society for Immunotherapy of Cancer (SITC) convened a panel of experts to determine how to design clinical trials with the greatest chance of demonstrating the benefits of intratumoral immunotherapy for patients with cancers across all stages of pathogenesis. METHODS: An Intratumoral Immunotherapy Clinical Trials Expert Panel composed of international key stakeholders from academia and industry was assembled. A multiple choice/free response survey was distributed to the panel, and the results of this survey were discussed during a half-day consensus meeting. Key discussion points are summarized in the following manuscript. RESULTS: The panel determined unique clinical trial designs tailored to different stages of cancer development-from premalignant to unresectable/metastatic-that can maximize the chance of capturing the effect of intratumoral immunotherapies. Design elements discussed included study type, patient stratification and exclusion criteria, indications of randomization, study arm determination, endpoints, biological sample collection, and response assessment with biomarkers and imaging. Populations to prioritize for the study of intratumoral immunotherapy, including stage, type of cancer and line of treatment, were also discussed along with common barriers to the development of these local treatments. CONCLUSIONS: The SITC Intratumoral Immunotherapy Clinical Trials Expert Panel has identified key considerations for the design and implementation of studies that have the greatest potential to capture the effect of intratumorally delivered immunotherapies. With more effective and standardized trial designs, the potential of intratumoral immunotherapy can be realized and lead to regulatory approvals that will extend the benefit of these local treatments to the patients who need them the most.

Severe acute myositis and myocarditis on initiation of 6-weekly pembrolizumab post-COVID-19 mRNA vaccination.

We describe three cases of critical acute myositis with myocarditis occurring within 22 days of each other at a single institution, all within 1 month of receiving the initial cycle of the anti-PD-1 drug pembrolizumab. Analysis of T cell receptor repertoires from peripheral blood and tissues revealed a high degree of clonal expansion and public clones between cases, with several T cell clones expanded within the skeletal muscle putatively recognizing viral epitopes. All patients had recently received a COVID-19 mRNA booster vaccine prior to treatment and were positive for SARS-CoV2 Spike antibody. In conclusion, we report a series of unusually severe myositis and myocarditis following PD-1 blockade and the COVID-19 mRNA vaccination.

Binimetinib in combination with nivolumab or nivolumab and ipilimumab in patients with previously treated microsatellite-stable metastatic colorectal cancer with RAS mutations in an open-label phase 1b/2 study.

BACKGROUND: In patients with previously treated RAS-mutated microsatellite-stable (MSS) metastatic colorectal cancer (mCRC), a multicenter open-label phase 1b/2 trial was conducted to define the safety and efficacy of the MEK1/MEK2 inhibitor binimetinib in combination with the immune checkpoint inhibitor (ICI) nivolumab (anti-PD-1) or nivolumab and another ICI, ipilimumab (anti-CTLA4). METHODS: In phase 1b, participants were randomly assigned to Arm 1A (binimetinib 45 mg twice daily [BID] plus nivolumab 480 mg once every 4 weeks [Q4W]) or Arm 1B (binimetinib 45 mg BID plus nivolumab 480 mg Q4W and ipilimumab 1 mg/kg once every 8 weeks [Q8W]) to determine the maximum tolerable dose (MTD) and recommended phase 2 dose (RP2D) of binimetinib. The MTD/RP2D was defined as the highest dosage combination that did not cause medically unacceptable dose-limiting toxicities in more than 35% of treated participants in Cycle 1. During phase 2, participants were randomly assigned to Arm 2A (binimetinib MTD/RP2D plus nivolumab) or Arm 2B (binimetinib MTD/RP2D plus nivolumab and ipilimumab) to assess the safety and clinical activity of these combinations. RESULTS: In phase 1b, 21 participants were randomized to Arm 1A or Arm 1B; during phase 2, 54 participants were randomized to Arm 2A or Arm 2B. The binimetinib MTD/RP2D was determined to be 45 mg BID. In phase 2, no participants receiving binimetinib plus nivolumab achieved a response. Of the 27 participants receiving binimetinib, nivolumab, and ipilimumab, the overall response rate was 7.4% (90% CI: 1.3, 21.5). Out of 75 participants overall, 74 (98.7%) reported treatment-related adverse events (AEs), of whom 17 (22.7%) reported treatment-related serious AEs. CONCLUSIONS: The RP2D binimetinib regimen had a safety profile similar to previous binimetinib studies or nivolumab and ipilimumab combination studies. There was a lack of clinical benefit with either drug combination. Therefore, these data do not support further development of binimetinib in combination with nivolumab or nivolumab and ipilimumab in RAS-mutated MSS mCRC. TRIAL REGISTRATION: NCT03271047 (09/01/2017).

Nilotinib in KIT-driven advanced melanoma: Results from the phase II single-arm NICAM trial.

Mucosal (MM) and acral melanomas (AM) are rare melanoma subtypes of unmet clinical need; 15%-20% harbor KIT mutations potentially targeted by small-molecule inhibitors, but none yet approved in melanoma. This multicenter, single-arm Phase II trial (NICAM) investigates nilotinib safety and activity in KIT mutated metastatic MM and AM. KIT mutations are identified in 39/219 screened patients (18%); of 29/39 treated, 26 are evaluable for primary analysis. Six patients were alive and progression free at 6 months (local radiology review, 25%); 5/26 (19%) had objective response at 12 weeks; median OS was 7.7 months; ddPCR assay correctly identifies KIT alterations in circulating tumor DNA (ctDNA) in 16/17 patients. Nilotinib is active in KIT-mutant AM and MM, comparable to other KIT inhibitors, with demonstrable activity in nonhotspot KIT mutations, supporting broadening of KIT evaluation in AM and MM. Our results endorse further investigations of nilotinib for the treatment of KIT-mutated melanoma. This clinical trial was registered with ISRCTN (ISRCTN39058880) and EudraCT (2009-012945-49).

A randomised phase 2 study of intermittent versus continuous dosing of dabrafenib plus trametinib in patients with BRAFV600 mutant advanced melanoma (INTERIM).

BACKGROUND: BRAF+MEK inhibitors extend life expectancy of patients with BRAFV600 mutant advanced melanoma. Acquired resistance limits duration of benefit, but preclinical and case studies suggest intermittent dosing could overcome this limitation. INTERIM was a phase 2 trial evaluating an intermittent dosing regimen. METHODS: Patients with BRAFV600 mutant advanced melanoma due to start dabrafenib+trametinib were randomised to receive either continuous (CONT), or intermittent (INT; dabrafenib d1-21, trametinib d1-14 every 28 days) dosing. A composite primary endpoint included progression-free survival (PFS) and quality of life (QoL). Secondary endpoints included response rate (ORR), overall survival (OS) and adverse events (AEs). Mutant BRAFV600E ctDNA was measured by droplet digital PCR (ddPCR), using mutant allele frequency of > 1 % as the detection threshold. RESULTS: 79 patients (39 INT, 40 CONT) were recruited; median age 67 years, 65 % AJCC (7th ed) stage IV M1c, 29 % had brain metastases. With 19 months median follow-up, INT was inferior in all efficacy measures: median PFS 8.5 vs 10.7mo (HR 1.39, 95 %CI 0.79-2.45, p = 0.255); median OS 18.1mo vs not reached (HR 1.69, 95 %CI 0.87-3.28, p = 0.121), ORR 57 % vs 77 %. INT patients experienced fewer treatment-related AEs (76 % vs 88 %), but more grade > 3 AEs (53 % vs 42 %). QoL favoured CONT. Detection of BRAFV600E ctDNA prior to treatment correlated with worse OS (HR 2.55, 95 %CI 1.25-5.21, p = 0.01) in both arms. A change to undetected during treatment did not significantly predict better OS. CONCLUSION: INTERIM findings are consistent with other recent clinical trials reporting that intermittent dosing does not improve efficacy of BRAF+MEK inhibitors.

Using nominal group technique to identify the planning considerations for UK Armed Forces medical personnel delivering defence engagement first aid training activities.

INTRODUCTION: Defence Medical Services personnel regularly deploy overseas to deliver training activities as part of defence engagement (DE) to positively influence partners and others. There remains scope for medical planners to enhance our understanding of how to optimally use medical staff and assets for DE. We aimed to develop a tool to improve planning for DE activities delivering first aid training. METHODS: We used nominal group technique to conduct a focus group with UK experts in planning first aid training DE activities to identify and prioritise important planning considerations within a conceptual framework based on the Defence Lines of Development. We validated and refined this framework with international experts from partner nation militaries to help strengthen the final planning tool. RESULTS: We developed a detailed tool covering training curriculum and logistical and infrastructure requirements to deliver safe and effective DE training activities. First aid training engagement priorities include being tailored to the training audience and in harmony with the national or military healthcare services of that country. Messaging around the women, peace and security agenda should be integrated into training packages at conception to be effective. CONCLUSIONS: We propose a planning tool to aid in designing first aid training that considers the necessary components to support meaningful education and effective engagement in support of UK's strategic goals. We welcome the use of and feedback on this tool and its impact to those planning first aid training activities as part of DE operations.

Clinical trial protocol for PanDox: a phase I study of targeted chemotherapy delivery to non-resectable primary pancreatic tumours using thermosensitive liposomal doxorubicin (ThermoDox®) and focused ultrasound.

BACKGROUND: The dense stroma of pancreatic ductal adenocarcinomas is a major barrier to drug delivery. To increase the local drug diffusion gradient, high doses of chemotherapeutic agent doxorubicin can be released from thermally-sensitive liposomes (ThermoDox®) using ultrasound-mediated hyperthermia at the tumour target. PanDox is designed as a Phase 1 single centre study to investigate enhancing drug delivery to adult patients with non-operable pancreatic ductal adenocarcinomas. The study compares a single cycle of either conventional doxorubicin alone or ThermoDox® with focused ultrasound-induced hyperthermia for targeted drug release. METHODS: Adults with non-resectable pancreatic ductal adenocarcinoma are allocated to receive a single cycle of either doxorubicin alone (Arm A) or ThermoDox® with focused ultrasound-induced hyperthermia (Arm B), based on patient- and tumour-specific safety conditions. Participants in Arm B will undergo a general anaesthetic and pre-heating of the tumour by extra-corporal focused ultrasound (FUS). Rather than employing invasive thermometry, ultrasound parameters are derived from a patient-specific treatment planning model to reach the 41 °C target temperature for drug release. ThermoDox® is then concurrently infused with further ultrasound exposure. Tumour biopsies at the targeted site from all patients are analysed post-treatment using high performance liquid chromatography to quantify doxorubicin delivered to the tumour. The primary endpoint is defined as a statistically significant enhancement in concentration of total intra-tumoural doxorubicin, comparing samples from patients receiving liposomal drug with FUS to free drug alone. Participants are followed for 21 days post-treatment to assess secondary endpoints, including radiological assessment to measure changes in tumour activity by Positron Emission Tomography Response Criteria in Solid Tumours (PERCIST) criteria, adverse events and patient-reported symptoms. DISCUSSION: This early phase study builds on previous work targeting tumours in the liver to investigate whether enhancement of chemotherapy delivery using ultrasound-mediated hyperthermia can be translated to the stroma-dense environment of pancreatic ductal adenocarcinoma. If successful, it could herald a new approach towards managing these difficult-to-treat tumours. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04852367 . Registered 21st April 2022. EudraCT number: 2019-003950-10 (Registered 2019) Iras Project ID: 272253 (Registered 2019) Ethics Number: 20/EE/0284.

Combination therapies for the optimisation of Bispecific T-cell Engagers in cancer treatment.

Bispecific T-cell engagers (BiTEs) redirect endogenous T-cell populations to cells expressing tumour-associated antigens to induce tumour cell killing. This inherently relies upon a cytotoxic T-cell population that is able to be recruited. In many cancers, immune checkpoints and other immunosuppressive factors in the tumour microenvironment lead to a population of anergic T-cells which cannot be redirected to tumour killing and thus impede the efficacy of BiTE therapy. Furthermore, there is evidence that BiTE therapy itself can increase immune checkpoint expression, and this is thought to be a major escape mechanism for the BiTE therapy blinatumomab. To overcome these inadequate T-cell responses, BiTEs may be combined with checkpoint inhibitors, chemotherapy, costimulatory molecules or oncolytic viruses. Study of these combinations is needed to expand the use of BiTEs in solid malignancies. This review covers the rationale, preclinical evidence and any clinical trials for these combination therapies and a few other less-studied combinations.

Tumor monocyte content predicts immunochemotherapy outcomes in esophageal adenocarcinoma.

For inoperable esophageal adenocarcinoma (EAC), identifying patients likely to benefit from recently approved immunochemotherapy (ICI+CTX) treatments remains a key challenge. We address this using a uniquely designed window-of-opportunity trial (LUD2015-005), in which 35 inoperable EAC patients received first-line immune checkpoint inhibitors for four weeks (ICI-4W), followed by ICI+CTX. Comprehensive biomarker profiling, including generation of a 65,000-cell single-cell RNA-sequencing atlas of esophageal cancer, as well as multi-timepoint transcriptomic profiling of EAC during ICI-4W, reveals a novel T cell inflammation signature (INCITE) whose upregulation correlates with ICI-induced tumor shrinkage. Deconvolution of pre-treatment gastro-esophageal cancer transcriptomes using our single-cell atlas identifies high tumor monocyte content (TMC) as an unexpected ICI+CTX-specific predictor of greater overall survival (OS) in LUD2015-005 patients and of ICI response in prevalent gastric cancer subtypes from independent cohorts. Tumor mutational burden is an additional independent and additive predictor of LUD2015-005 OS. TMC can improve patient selection for emerging ICI+CTX therapies in gastro-esophageal cancer.

Tebentafusp in combination with durvalumab and/or tremelimumab in patients with metastatic cutaneous melanoma: a phase 1 study.

BACKGROUND: Immune checkpoint inhibitors have significantly improved outcomes in first line cutaneous melanoma. However, there is a high unmet need for patients who progress on these therapies and combination therapies are being explored to improve outcomes. Tebentafusp is a first-in-class gp100×CD3 ImmTAC bispecific that demonstrated overall survival (OS) benefit (HR 0.51) in metastatic uveal melanoma despite a modest overall response rate of 9%. This phase 1b trial evaluated the safety and initial efficacy of tebentafusp in combination with durvalumab (anti-programmed death ligand 1 (PDL1)) and/or tremelimumab (anti-cytotoxic T lymphocyte-associated antigen 4) in patients with metastatic cutaneous melanoma (mCM), the majority of whom progressed on prior checkpoint inhibitors. METHODS: In this open-label, multicenter, phase 1b, dose-escalation trial, HLA-A*02:01-positive patients with mCM received weekly intravenous tebentafusp with increasing monthly doses of durvalumab and/or tremelimumab starting day 15 of each cycle. The primary objective was to identify the maximum tolerated dose (MTD) or recommended phase 2 dose for each combination. Efficacy analyses were performed in all tebentafusp with durvalumab±tremelimumab treated patients with a sensitivity analysis in those who progressed on prior anti-PD(L)1 therapy. RESULTS: 85 patients were assigned to receive tebentafusp in combination with durvalumab (n=43), tremelimumab (n=13), or durvalumab and tremelimumab (n=29). Patients were heavily pretreated with a median of 3 prior lines of therapy, including 76 (89%) who received prior anti-PD(L)1. Maximum target doses of tebentafusp (68 mcg) alone or in combination with durvalumab (20 mg/kg) and tremelimumab (1 mg/kg) were tolerated; MTD was not formally identified for any arm. Adverse event profile was consistent with each individual therapy and there were no new safety signals nor treatment-related deaths. In the efficacy subset (n=72), the response rate was 14%, tumor shrinkage rate was 41% and 1-year OS rate was 76% (95% CI: 70% to 81%). The 1-year OS for triplet combination (79%; 95% CI: 71% to 86%) was similar to tebentafusp plus durvalumab (74%; 95% CI: 67% to 80%). CONCLUSION: At maximum target doses, the safety of tebentafusp with checkpoint inhibitors was consistent with safety of each individual therapy. Tebentafusp with durvalumab demonstrated promising efficacy in heavily pretreated patients with mCM, including those who progressed on prior anti-PD(L)1. TRIAL REGISTRATION NUMBER: NCT02535078.

Multi-cancer early detection test in symptomatic patients referred for cancer investigation in England and Wales (SYMPLIFY): a large-scale, observational cohort study.

BACKGROUND: Analysis of circulating tumour DNA could stratify cancer risk in symptomatic patients. We aimed to evaluate the performance of a methylation-based multicancer early detection (MCED) diagnostic test in symptomatic patients referred from primary care. METHODS: We did a multicentre, prospective, observational study at National Health Service (NHS) hospital sites in England and Wales. Participants aged 18 or older referred with non-specific symptoms or symptoms potentially due to gynaecological, lung, or upper or lower gastrointestinal cancers were included and gave a blood sample when they attended for urgent investigation. Participants were excluded if they had a history of or had received treatment for an invasive or haematological malignancy diagnosed within the preceding 3 years, were taking cytotoxic or demethylating agents that might interfere with the test, or had participated in another study of a GRAIL MCED test. Patients were followed until diagnostic resolution or up to 9 months. Cell-free DNA was isolated and the MCED test performed blinded to the clinical outcome. MCED predictions were compared with the diagnosis obtained by standard care to establish the primary outcomes of overall positive and negative predictive value, sensitivity, and specificity. Outcomes were assessed in participants with a valid MCED test result and diagnostic resolution. SYMPLIFY is registered with ISRCTN (ISRCTN10226380) and has completed follow-up at all sites. FINDINGS: 6238 participants were recruited between July 7 and Nov 30, 2021, across 44 hospital sites. 387 were excluded due to staff being unable to draw blood, sample errors, participant withdrawal, or identification of ineligibility after enrolment. Of 5851 clinically evaluable participants, 376 had no MCED test result and 14 had no information as to final diagnosis, resulting in 5461 included in the final cohort for analysis with an evaluable MCED test result and diagnostic outcome (368 [6·7%] with a cancer diagnosis and 5093 [93·3%] without a cancer diagnosis). The median age of participants was 61·9 years (IQR 53·4-73·0), 3609 (66·1%) were female and 1852 (33·9%) were male. The MCED test detected a cancer signal in 323 cases, in whom 244 cancer was diagnosed, yielding a positive predictive value of 75·5% (95% CI 70·5-80·1), negative predictive value of 97·6% (97·1-98·0), sensitivity of 66·3% (61·2-71·1), and specificity of 98·4% (98·1-98·8). Sensitivity increased with increasing age and cancer stage, from 24·2% (95% CI 16·0-34·1) in stage I to 95·3% (88·5-98·7) in stage IV. For cases in which a cancer signal was detected among patients with cancer, the MCED test's prediction of the site of origin was accurate in 85·2% (95% CI 79·8-89·3) of cases. Sensitivity 80·4% (95% CI 66·1-90·6) and negative predictive value 99·1% (98·2-99·6) were highest for patients with symptoms mandating investigation for upper gastrointestinal cancer. INTERPRETATION: This first large-scale prospective evaluation of an MCED diagnostic test in a symptomatic population demonstrates the feasibility of using an MCED test to assist clinicians with decisions regarding urgency and route of referral from primary care. Our data provide the basis for a prospective, interventional study in patients presenting to primary care with non-specific signs and symptoms. FUNDING: GRAIL Bio UK.

Phase 1 study of the pan-RAF inhibitor tovorafenib in patients with advanced solid tumors followed by dose expansion in patients with metastatic melanoma.

PURPOSE: Genomic alterations of BRAF and NRAS are oncogenic drivers in malignant melanoma and other solid tumors. Tovorafenib is an investigational, oral, selective, CNS-penetrant, small molecule, type II pan­RAF inhibitor. This first-in-human phase 1 study explored the safety and antitumor activity of tovorafenib. METHODS: This two-part study in adult patients with relapsed or refractory advanced solid tumors included a dose escalation phase and a dose expansion phase including molecularly defined cohorts of patients with melanoma. Primary objectives were to evaluate the safety of tovorafenib administered once every other day (Q2D) or once weekly (QW), and to determine the maximum-tolerated and recommended phase 2 dose (RP2D) on these schedules. Secondary objectives included evaluation of antitumor activity and tovorafenib pharmacokinetics. RESULTS: Tovorafenib was administered to 149 patients (Q2D n = 110, QW n = 39). The RP2D of tovorafenib was defined as 200 mg Q2D or 600 mg QW. In the dose expansion phase, 58 (73%) of 80 patients in Q2D cohorts and 9 (47%) of 19 in the QW cohort had grade ≥ 3 adverse events. The most common of these overall were anemia (14 patients, 14%) and maculo-papular rash (8 patients, 8%). Responses were seen in 10 (15%) of 68 evaluable patients in the Q2D expansion phase, including in 8 of 16 (50%) patients with BRAF mutation-positive melanoma naïve to RAF and MEK inhibitors. In the QW dose expansion phase, there were no responses in 17 evaluable patients with NRAS mutation-positive melanoma naïve to RAF and MEK inhibitors; 9 patients (53%) had a best response of stable disease. QW dose administration was associated with minimal accumulation of tovorafenib in systemic circulation in the dose range of 400-800 mg. CONCLUSIONS: The safety profile of both schedules was acceptable, with QW dosing at the RP2D of 600 mg QW preferred for future clinical studies. Antitumor activity of tovorafenib in BRAF-mutated melanoma was promising and justifies continued clinical development across multiple settings. GOV IDENTIFIER: NCT01425008.

Adjuvant Nivolumab versus Ipilimumab in Resected Stage III/IV Melanoma: 5-Year Efficacy and Biomarker Results from CheckMate 238.

PURPOSE: In the phase III CheckMate 238 study, adjuvant nivolumab significantly improved recurrence-free survival (RFS) and distant metastasis-free survival versus ipilimumab in patients with resected stage IIIB-C or stage IV melanoma, with benefit sustained at 4 years. We report updated 5-year efficacy and biomarker findings. PATIENTS AND METHODS: Patients with resected stage IIIB-C/IV melanoma were stratified by stage and baseline programmed death cell ligand 1 (PD-L1) expression and received nivolumab 3 mg/kg every 2 weeks or ipilimumab 10 mg/kg every 3 weeks for four doses and then every 12 weeks, both intravenously for 1 year until disease recurrence, unacceptable toxicity, or withdrawal of consent. The primary endpoint was RFS. RESULTS: At a minimum follow-up of 62 months, RFS with nivolumab remained superior to ipilimumab (HR = 0.72; 95% confidence interval, 0.60-0.86; 5-year rates of 50% vs. 39%). Five-year distant metastasis-free survival (DMFS) rates were 58% with nivolumab versus 51% with ipilimumab. Five-year overall survival (OS) rates were 76% with nivolumab and 72% with ipilimumab (75% data maturity: 228 of 302 planned events). Higher levels of tumor mutational burden (TMB), tumor PD-L1, intratumoral CD8+ T cells and IFNγ-associated gene expression signature, and lower levels of peripheral serum C-reactive protein were associated with improved RFS and OS with both nivolumab and ipilimumab, albeit with limited clinically meaningful predictive value. CONCLUSIONS: Nivolumab is a proven adjuvant treatment for resected melanoma at high risk of recurrence, with sustained, long-term improvement in RFS and DMFS compared with ipilimumab and high OS rates. Identification of additional biomarkers is needed to better predict treatment outcome. See related commentary by Augustin and Luke, p. 3253.

PemBla: A Phase 1 study of intravesical pembrolizumab in recurrent non-muscle-invasive bladder cancer.

Objectives: This study aimed to investigate the anti-PD-1 inhibitor pembrolizumab as a potential agent for use in non-muscle-invasive bladder cancer (NMIBC) by conducting a Phase 1 safety run-in study to assess the safety and tolerability of intravesical pembrolizumab after transurethral resection of the bladder tumour (TURBT). Patients and methods: Eligible patients had recurrent NMIBC for which adjuvant treatment post TURBT was a reasonable treatment option, Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0-1 and adequate end-organ function. Pembrolizumab was administered by intravesical instillation once weekly for a total of six doses. Intra-patient dose escalation was performed in three paired patient cohorts with doses starting at 50 mg and increasing through 100 mg to a maximum of 200 mg. Adverse events (AEs) were assessed using Common Terminology Criteria for Adverse Events (CTCAE) v4.03 with dose limiting toxicity (DLT) defined as a clinically significant, drug-related, Grade 4 haematological or Grade 3 or higher non-haematological toxicity occurring within 7 days of administration of the first treatment at a given dose for that patient. Results: Six patients were treated with no DLTs seen during dose escalation. Drug-related AEs were of low grade and included dysuria and fatigue. All patients completed six doses of treatment as planned. Pharmacokinetic and pharmacodynamic assays did not detect any pembrolizumab in the serum following repeated intravesical administration, and no changes in peripheral immune cell populations were observed. Conclusions: Administration of intravesical pembrolizumab was well tolerated and did not raise any safety concerns in patients with NMIBC following TURBT. There was no evidence of systemic absorption or systemic immune effects following intravesical administration. Further studies are required to assess whether intravesical administration has anti-tumour activity.

Pseudotime dynamics of T cells in pancreatic ductal adenocarcinoma inform distinct functional states within the regulatory and cytotoxic T cells.

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest types of cancer and has a 5-year survival of less than 8% owing to its complex biology. As PDAC is refractory to immunotherapy, we need to understand the functional dynamics of T cells in the PDAC microenvironment to develop alternative therapeutic strategies. In this study, we performed RNA velocity-based pseudotime analysis on a scRNA-seq dataset from surgically resected human PDAC specimens to gain insight into temporal gene expression patterns that best characterize the cell fates. The tumor microenvironment was seen to encompass a range of terminal states for the T cell trajectories with suppressive and non-tumor-responsive T cells dominating them. However, the results also reveal the existence of a functional branch of the T cell population that was not transitioning to exhausted and senescent states. These findings reveal various microenvironmental signals driving T cell patterns which can be useful in identifying new therapeutic avenues.

Circulating galectin-1 delineates response to bevacizumab in melanoma patients and reprograms endothelial cell biology.

Blockade of vascular endothelial growth factor (VEGF) signaling with bevacizumab, a humanized anti-VEGF monoclonal antibody (mAb), or with receptor tyrosine kinase inhibitors, has improved progression-free survival and, in some indications, overall survival across several types of cancers by interrupting tumor angiogenesis. However, the clinical benefit conferred by these therapies is variable, and tumors from treated patients eventually reinitiate growth. Previously we demonstrated, in mouse tumor models, that galectin-1 (Gal1), an endogenous glycan-binding protein, preserves angiogenesis in anti-VEGF-resistant tumors by co-opting the VEGF receptor (VEGFR)2 signaling pathway in the absence of VEGF. However, the relevance of these findings in clinical settings is uncertain. Here, we explored, in a cohort of melanoma patients from AVAST-M, a multicenter, open-label, randomized controlled phase 3 trial of adjuvant bevacizumab versus standard surveillance, the role of circulating plasma Gal1 as part of a compensatory mechanism that orchestrates endothelial cell programs in bevacizumab-treated melanoma patients. We found that increasing Gal1 levels over time in patients in the bevacizumab arm, but not in the observation arm, significantly increased their risks of recurrence and death. Remarkably, plasma Gal1 was functionally active as it was able to reprogram endothelial cell biology, promoting migration, tubulogenesis, and VEGFR2 phosphorylation. These effects were prevented by blockade of Gal1 using a newly developed fully human anti-Gal1 neutralizing mAb. Thus, using samples from a large-scale clinical trial from stage II and III melanoma patients, we validated the clinical relevance of Gal1 as a potential mechanism of resistance to bevacizumab treatment.

WNT5A-ROR2 axis mediates VEGF dependence of BRAF mutant melanoma.

PURPOSE: Despite recent advances, approximately 50% of patient with metastatic melanoma eventually succumb to the disease. Patients with melanomas harboring a BRAF mutation (BRAFMut) have a worse prognosis than those with wildtype (BRAFWT) tumors. Unexpectedly, interim AVAST-M Phase III trial data reported benefit from adjuvant anti-VEGF bevacizumab only in the BRAFMut group. We sought to find mechanisms underpinning this sensitivity. METHODS: We investigated this finding in vitro and in vivo using melanoma cell lines and clones generated by BRAFV600E knock-in on a BRAFWT background. RESULTS: Compared with BRAFWT cells, isogenic BRAFV600E clones secreted more VEGF and exhibited accelerated growth rates as spheroids and xenografts, which were more vascular and proliferative. Recapitulating AVAST-M findings, bevacizumab affected only BRAFV600E xenografts, inducing significant tumor growth delay, reduced vascularity and increased necrosis. We identified 814 differentially expressed genes in isogenic BRAFV600E/BRAFWT clones. Of 61 genes concordantly deregulated in clinical melanomas ROR2 was one of the most upregulated by BRAFV600E. ROR2 was shown to be RAF-MEK regulated in BRAFV600E cells and its depletion suppressed VEGF secretion down to BRAFWT levels. The ROR2 ligand WNT5A was also overexpressed in BRAFMut melanomas, and in ROR2-overexpressing BRAFV600E cells MEK inhibition downregulated WNT5A and VEGF secretion. CONCLUSIONS: These data implicate WNT5A-ROR2 in VEGF secretion, vascularity, adverse outcomes and bevacizumab sensitivity of BRAFMut melanomas, suggesting that this axis has potential therapeutic relevance.

A Phase 1B open-label study of gedatolisib (PF-05212384) in combination with other anti-tumour agents for patients with advanced solid tumours and triple-negative breast cancer.

BACKGROUND: This Phase 1b study (B2151002) evaluated the PI3K/mTOR inhibitor gedatolisib (PF-05212384) in combination with other anti-tumour agents in advanced solid tumours. METHODS: Patients with various malignancies were administered gedatolisib (90‒310 mg intravenously every week [QW]) plus docetaxel (arm A) or cisplatin (arm B) (each 75 mg/m2 intravenously Q3W) or dacomitinib (30 or 45 mg/day orally). The safety and tolerability of combination therapies were assessed during dose escalation; objective response (OR) and safety were assessed during dose expansion. RESULTS: Of 110 patients enrolled, 107 received gedatolisib combination treatment. Seven of 70 (10.0%) evaluable patients had dose-limiting toxicities; the most common was grade 3 oral mucositis (n = 3). Based upon reprioritisation of the sponsor's portfolio, dose expansion focused on arm B, gedatolisib (180 mg QW) plus cisplatin in patients (N = 22) with triple-negative breast cancer (TNBC). OR (95% CI) was achieved in four of ten patients in first-line (overall response rate 40.0% [12.2-73.8%]) and four of 12 in second/third-line (33.3% [9.9-65.1%]) settings. One patient in each TNBC arm (10%, first-line; 8.3%, second/third-line) achieved a complete response. CONCLUSIONS: Gedatolisib combination therapy showed an acceptable tolerability profile, with clinical activity at the recommended Phase 2 dose in patients with TNBC. CLINICAL TRIAL: ClinicalTrial.gov: NCT01920061.