Citations

Since the first approval for immune checkpoint inhibitors (ICIs) for the treatment of cutaneous melanoma more than a decade ago, immunotherapy has completely transformed the treatment landscape of this chemotherapy-resistant disease. Combination regimens including ICIs directed against programmed cell death protein 1 (PD-1) with anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) agents or, more recently, anti-lymphocyte-activation gene 3 (LAG-3) agents, have gained regulatory approvals for the treatment of metastatic cutaneous melanoma, with long-term follow-up data suggesting the possibility of cure for some patients with advanced disease. In the resectable setting, adjuvant ICIs prolong recurrence-free survival and several are FDA-approved. Although not yet approved, neoadjuvant ICIs have also shown to improve event-free survival and remains an ongoing area of investigation. Other immunotherapy strategies, such as oncolytic virotherapy for injectable cutaneous melanoma, bispecific T-cell engager therapy for HLA-A*02:01 genotype-positive uveal melanoma, and lifileucel, an autologous tumor-infiltrating lymphocyte therapy, for unresectable or metastatic melanoma are also available to patients. Despite the remarkable efficacy of these regimens for many patients with cutaneous melanoma, traditional immunotherapy biomarkers (ie, programmed death-ligand 1 expression, tumor mutational burden, T-cell infiltrate and/or microsatellite stability) have failed to reliably predict response. Furthermore, ICIs are associated with unique toxicity profiles, particularly for the highly active combination of anti-PD-1 plus anti-CTLA-4 agents. The Society for Immunotherapy of Cancer (SITC) convened a panel of experts to develop this clinical practice guideline on immunotherapy for the treatment of melanoma, including rare subtypes of the disease (eg, uveal, mucosal), with the goal of improving patient care by providing guidance to the oncology community. Drawing from published data and clinical experience, the Expert Panel developed evidence- and consensus-based recommendations for healthcare professionals using immunotherapy to treat melanoma, with topics including therapy selection in the advanced and perioperative settings, intratumoral immunotherapy, when to use immunotherapy for patients with BRAF V600-mutated disease, management of patients with brain metastases, evaluation of treatment response, special patient populations, patient education, quality of life, and survivorship, among others.

2529 Background: Tumor expression of the antiphagocytic protein CD47 (integrin associated protein) may lead to immunotherapy resistance (IO-R). PF-07257876 is a novel, IgG1, Fc-active, bispecific antibody targeting CD47 and PD-L1 designed to reverse IO-R, decrease anemia risk, and eliminate a priming dose. We report a Phase 1 dose escalation study (NCT04881045) in patients (pts) with advanced solid tumors, both IO-refractory and IO-naïve. Methods: The study enrolled pts ≥18 yrs with advanced non–small-cell lung carcinoma (NSCLC) and squamous cell carcinoma of the head and neck (SCCHN) with PD-L1 expression >1% post anti-PD-1/PD-L1 therapy. Pts with other PD-L1+ tumors known to express CD47 were included (prior IO not required). Pts received PF-07257876 at escalating dose levels in 28-day cycles. Primary objectives were safety (dose-limiting toxicity [DLT] rate), tolerability, and determination of Recommended Phase 2 Dose (RP2D). Secondary and exploratory objectives included pharmacokinetics (PK), blood receptor occupancy (RO), CD47 levels by immunohistochemistry (IHC), tissue biopsy findings, and objective response rate (ORR) per RECIST v.1.1. Results: As of 20OCT2022, 18 pts were enrolled (NSCLC: n = 6; SCCHN: n = 4; other: n = 8). Median (range) age 68 (46–79) yrs. PF-07257876 was given at ascending doses, 150-2400 mg by subcutaneous (SC) injection or SC infusion every 2 weeks. 16 (89%) pts had treatment-related adverse events (TRAEs): Grades 1/2: n = 12 (67%); Grade 3: n = 1 (6%); Grade 4: n = 3 (17%); no Grade 5. Most common TRAEs: injection site reaction/erythema (n = 13, 72%), thrombocytopenia (n = 6, 33%), anemia (n = 5, 28%), and nausea (n = 4, 22%). DLTs occurred in 2 of 3 pts at the highest tested dose (Grade 4 neutropenia and thrombocytopenia, n = 1; Grade 4 thrombocytopenia, n = 1; both pts recovered). One pt with IO-R SCCHN had a confirmed partial response (duration of response 16 wks). ORR was 5.6% (1/18). Drug exposure increase after 1st dose was not dose proportional. Blood RO was > 95% for PD-L1 and > 70% for CD47 with drug exposure. All pts’ baseline CD47 IHC levels were moderate to high. Pharmacodynamics cytokine profiling showed notable dose-response increases of IFNg, TNFa, CXCL9/10, CCL3/4, without IL-6 increase. Conclusions: PF-07257876 was well tolerated with manageable toxicity. Incidence and grade of anemia or thrombocytopenia were manageable. Target engagement of CD47 and PD-L1 in peripheral blood was high. Innate and adaptive cytokine modulation was observed. Antitumor activity was modest. Expansion is ongoing at 1800 mg. Clinical trial information: NCT04881045 .

Talimogene laherparepvec (T-VEC) plus ipilimumab has demonstrated greater antitumor activity versus ipilimumab alone, without additional toxicity, in patients with advanced melanoma. Here, we report the 5-year outcomes from a randomized phase II study. These data provide the longest efficacy and safety follow-up for patients with melanoma treated with a combination of an oncolytic virus and a checkpoint inhibitor. Eligible patients with unresectable stage IIIB‒IV melanoma were randomized 1:1 to receive T-VEC plus ipilimumab or ipilimumab alone. T-VEC was administered intralesionally at 10 6 plaque-forming units (PFU)/mL in week 1, followed by 10 8 PFU/mL in week 4 and every 2 weeks thereafter. Ipilimumab (3 mg/kg every 3 weeks; ≤4 doses) was administered intravenously starting at week 1 in the ipilimumab arm and week 6 in the combination arm. The primary end point was investigator-assessed objective response rate (ORR) per immune-related response criteria; key secondary end points included durable response rate (DRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Overall, 198 patients were randomized to receive the combination (n=98) or ipilimumab (n=100). The combination improved the ORR versus ipilimumab (35.7% vs 16.0%; OR 2.9; 95% CI 1.5 to 5.7; p=0.003). DRR was 33.7% and 13.0% (unadjusted OR 3.4; 95% CI 1.7 to 7.0; descriptive p=0.001), respectively. Among the objective responders, the median DOR was 69.2 months (95% CI 38.5 to not estimable) with the combination and was not reached with ipilimumab. Median PFS was 13.5 months with the combination and 6.4 months with ipilimumab (HR 0.78; 95% CI 0.55 to 1.09; descriptive p=0.14). Estimated 5-year OS was 54.7% (95% CI 43.9 to 64.2) in the combination arm and 48.4% (95% CI 37.9 to 58.1) in the ipilimumab arm. Forty-seven (48.0%) and 65 (65.0%) patients in the combination and ipilimumab arms, respectively, received subsequent therapies. No new safety signals were reported. At the 5-year follow-up, the improved response rates observed with T-VEC plus ipilimumab were durable. This is the first randomized controlled study of the combination of an oncolytic virus and a checkpoint inhibitor that meets its primary end point.Trial registration number: NCT01740297 .

2651 Background: Etigilimab (etig), a humanized IgG1 monoclonal antibody, blocks TIGIT interaction with PVR (poliovirus receptor) and inhibits downstream signalling with target cell killing. Etig +/- nivolumab (nivo) showed acceptable safety and preliminary activity in a FIH Phase 1a/b study in solid tumors. ACTIVATE, an open-label Phase 1b/2 basket study is evaluating further efficacy, safety, tolerability and PK/PD of etig+nivo. This is a preliminary efficacy and safety analysis from ACTIVATE. Methods: Subjects with advanced/metastatic solid tumors without curative/standard of care therapies are given IV etig+nivo Q2W until disease progression or intolerable toxicity. Six open cohorts are enrolling in parallel: endometrial cancer (post-front-line platinum), endometrial cancer (2-3 prior lines), PD-L1+ checkpoint-inhibitor-naïve (CPI-n) cervical cancer, rare cancers (germ cell tumor (GCT), sarcoma, uveal melanoma), ovarian cancer (post-front-line platinum) and TMB-h/MSS, (TMB >10mut/mb) tumors. Tumor assessments are done every 8 weeks following baseline scan. Primary endpoint is investigator-assessed ORR by RECIST 1.1. Secondary endpoints include duration of response and safety. Results: Of 27 efficacy-evaluable subjects enrolled in the 6 open cohorts with minimum 1 staging scan or radiological/clinical progression at data cut-off of 02/10/22, 12 had clinical benefit with 1 complete response (CR), 2 partial responses (PRs) and 9 stable diseases (SDs) and 15 had radiological/clinical progressive disease (PD), with an overall response rate (ORR) of 11% and disease control rate (DCR) of 44%. Conclusions: Etig+nivo is safe and well tolerated with no new safety signals. Early efficacy was noted in cervical cancer (1CR, 1PR and 1SD) and uveal melanoma (3 SDs >20 weeks). Encouraging activity was also noted in ovarian cancer and post-CPI treated TMB-H/MSS NSCLC. These early data support continued evaluation of the combination of etig+nivo. Clinical activity was notable as below. Clinical trial information: NCT04761198. [Table: see text]

Background Most patients with advanced melanomas relapse after checkpoint blockade therapy. Thus, immunotherapies are needed that can be applied safely early, in the adjuvant setting. Seviprotimut-L is a vaccine containing human melanoma antigens, plus alum. To assess the efficacy of seviprotimut-L, the Melanoma Antigen Vaccine Immunotherapy Study (MAVIS) was initiated as a three-part multicenter, double-blind, placebo-controlled phase III trial. Results from part B1 are reported here. Methods Patients with AJCC V.7 stage IIB-III cutaneous melanoma after resection were randomized 2:1, with stage stratification (IIB/C, IIIA, IIIB/C), to seviprotimut-L 40 mcg or placebo. Recurrence-free survival (RFS) was the primary endpoint. For an hypothesized HR of 0.625, one-sided alpha of 0.10, and power 80%, target enrollment was 325 patients. Results For randomized patients (n=347), arms were well-balanced, and treatment-emergent adverse events were similar for seviprotimut-L and placebo. For the primary intent-to-treat endpoint of RFS, the estimated HR was 0.881 (95% CI: 0.629 to 1.233), with stratified logrank p=0.46. However, estimated HRs were not uniform over the stage randomized strata, with HRs (95% CIs) for stages IIB/IIC, IIIA, IIIB/IIIC of 0.67 (95% CI: 0.37 to 1.19), 0.72 (95% CI: 0.35 to 1.50), and 1.19 (95% CI: 0.72 to 1.97), respectively. In the stage IIB/IIC stratum, the effect on RFS was greatest for patients <60 years old (HR=0.324 (95% CI: 0.121 to 0.864)) and those with ulcerated primary melanomas (HR=0.493 (95% CI: 0.255 to 0.952)). Conclusions Seviprotimut-L is very well tolerated. Exploratory efficacy model estimation supports further study in stage IIB/IIC patients, especially younger patients and those with ulcerated melanomas. Trial registration number NCT01546571.

10017 Background: Seviprotimut-L is a vaccine prepared from antigens of 3 human melanoma cell lines, administered with alum. Prior formulations induced T cell and antibody responses and improved survival in a small phase II clinical trial. Part B1 of MAVIS (Melanoma Antigen Vaccine Immunotherapy Study, a three part, Phase III clinical program), was a multicenter, double-blind, placebo-controlled trial to assess efficacy of seviprotimut-L, with the primary endpoint of relapse-free survival (RFS). The goal of Part B1 was to guide design of the pivotal Part B2. Methods: Patients with AJCC v7 stage IIB-III cutaneous melanoma, after surgical resection, age 18-75, ECOG PS 0-1, were randomized 2:1 to seviprotimut-L 40 mcg or placebo, injected subcutaneously every 2 weeks x 5, then monthly x 4, then every 3 months x 9. Patients were stratified by stage (IIB/C, IIIA, IIIB/C). Target enrollment was 325. The study was powered for assessment of RFS, with target hazard ratio (HR) of 0.625, one-sided alpha of 0.10, and power 80%. Final data are presented. Results: 347 patients were randomized. Arms were well-balanced. Treatment-related adverse events (AEs) led to discontinuation in 0.4% and 0%, respectively, for vaccine and placebo arms. There were no treatment-related SAEs. By intent-to-treat (ITT) analysis, RFS was not significantly longer for seviprotimut-L in the full study population but trended toward benefit (HR 0.88). Subgroup analysis based on planned stratification revealed the hazard ratio (HR) for the Stage IIB/IIC subset (randomization stratum, n=111) to be 0.65 (95% CI [0.37, 1.17]), favoring seviprotimut-L. Age can decrease immune competence: RFS was longer with vaccine for patients age <60 overall (N = 191, HR = 0.64 [0.38, 1.08]) and among Stage IIB/C patients (N = 52, HR = 0.32 [0.12, 0.86]). The effect modification interaction p value for age for stage IIB/IIC patients was 0.056. In a multivariable RFS model, for IIB/IIC patients <60 with ulceration (n=38), HR = 0.209 [0.07,0.61]. For overall survival, for patients < 60, HR = 0.41 [0.33,1.14] (n=191, 19 deaths) and for those ≥60, HR = 0.92 [0.39,2.12] (n = 156, 24 deaths). Conclusions: Seviprotimut-L is very well-tolerated. Subgroup efficacy analyses identified populations who may benefit from Seviprotimut-L: those with Stage IIB/IIC melanoma and those under age 60. These data support design of the definitive part B2 of the MAVIS phase III trial to test seviprotimut-L for stage IIB/C patients, with stratification by age and ulceration. Clinical trial information: NCT01546571.

10006 Background: Treatment options are limited for patients with advanced melanoma who have progressed on checkpoint inhibitors and targeted therapies. Adoptive cell therapy using tumor-infiltrating lymphocytes (TIL) leverages and enhances the body’s natural defense against cancer and has shown durable responses in heavily pretreated melanoma patients. Methods: C-144-01 is a global Phase 2 open-label, multicenter study of efficacy & safety of lifileucel in patients with unresectable metastatic melanoma who have progressed on checkpoint inhibitors and BRAF/MEK inhibitors, if BRAFv600 mutant. We report on Cohort 2 (N = 66) patients who have received TIL. Tumors were resected at local institutions, processed in central GMP facilities for TIL production, manufactured, cryopreserved & shipped back to sites in a 22-day process. Therapy consisted of one week of lymphodepletion, a single lifileucel infusion, and up to 6 IL-2 doses. ORR was based on RECIST v1.1 by investigator assessment. Data cutoff was Feb 2, 2020. Results: Baseline characteristics: 3.3 mean prior therapies (anti-PD1 100%; anti-CTLA-4 80%; BRAF/MEK inhibitor 23%), high baseline tumor burden (106 mm mean target lesion sum of diameters), 44% liver/brain lesions, 40.9% LDH > ULN. ORR by investigator was 36.4% (2 CR, 22 PR) and DCR was 80.3%. Mean time to response was 1.9 months (range: 1.3-5.6). After a median study follow-up of 17.0 months, median DOR (mDOR) was still not reached. Six responders have progressed, 2 have died and 2 started other anti-cancer therapy without progression. The adverse event profile was consistent with the underlying advanced disease and the lymphodepletion and IL-2 regimens. Additional follow-up data will be available for presentation. Conclusions: Lifileucel treatment results in a 36.4% ORR and mDOR was not reached at 17.0 months of median study follow up in a heavily pretreated metastatic melanoma patients with high baseline disease burden who progressed on multiple prior therapies, including anti-PD1 and BRAF/MEK inhibitors, if BRAFv600 mutant. Clinical trial information: NCT02360579.

9037 Background: Therapies for aBCC, which includes metastatic (m) and locally advanced (la) BCC, are limited. Abnormal Hedgehog pathway signaling is a key driver in BCC pathogenesis. Primary analysis of the pivotal ERIVANCE BCC trial of vismodegib, an oral hedgehog pathway inhibitor (HPI), demonstrated an objective response rate (ORR) of 30% and 43%, in mBCC and laBCC patients, respectively, with a median duration of response (DOR) of 7.6 months. We present safety and investigator (INV) assessed efficacy results 18 months (29 May 2012) after primary analysis (26 Nov 2010). Methods: Multicenter, international, nonrandomized study in patients (N=104) with radiographically measurable mBCC or laBCC (surgery inappropriate due to multiple recurrence, or substantial morbidity or deformity anticipated) receiving 150 mg oral vismodegib daily until disease progression or intolerable toxicity. Key secondary endpoints included INV-assessed ORR, progression-free survival (PFS), DOR, overall survival (OS), and safety. Results: At data cutoff, 21 patients continued to undergo protocol-specified assessments and 56 patients were in survival follow-up. The median dose intensity was comparable with primary analysis. ORR was 48.5%, mBCC; 60.3%, laBCC, comparable with primary analysis. However, median DOR improved (mBCC=14.7; laBCC=20.3 months). The median OS for mBCC was 30.9 months but not estimable in laBCC. Adverse events remained consistent, with muscle spasm, alopecia, dysgeusia, weight decrease, and fatigue most frequently reported. Eleven more deaths were reported in the update period after primary analysis; these occurred in survival follow-up and were not drug-related. Conclusions: Vismodegib is the first FDA-approved HPI; thus, long-term efficacy and safety data are particularly relevant. 18-month update data confirmed prolonged responses and consistent safety in vismodegib-treated aBCC patients. Clinical trial information: NCT00833417.

9016 Background: The MAP kinase (MAPK) pathway is of critical importance for keratinocyte proliferation and maturation and is essential for epidermal homeostasis. Occurrence of hyperproliferative skin lesions including keratoacanthomas (KA) and cuSCC are considered a class effect of BRAFi [Anforth 2012, Chu 2012, Mattei 2012]. These effects, as well as promotion of pre-existing RAS-driven malignancies, may be caused by paradoxical activation of the MAPK pathway downstream of BRAF in wild-type BRAF cells. As MEK inhibition blocks downstream MAPK signaling, it was hypothesized that addition of a MEKi to a BRAFi would abrogate these effects [Su, 2012]. Methods: This 4-part phase I/II study enrolled 365 BRAFV600E/Kmutated MM pts in Parts B-D. In part C, 162 pts (BRAFi and MEKi treatment-naïve, ≥ 18 yrs; ECOG PS <2; RECIST measurable disease) were randomized to D monotherapy 150mg BID (D mono) vs. the combination of D (150 mg BID) and T (1 mg or 2 mg QD). Primary endpoints included safety and efficacy. Occurrence of cuSCC (including KA) across three arms in Part C and secondary malignancies with D+T across all Parts are provided below. Results: The difference in incidence of cuSCC between D mono and the D+T (150/1) was statistically significant, whereas the difference in incidence between D mono and D+T (150/2) was not. The median time to onset of cuSCC was 30 days in D mono compared to 282 and 152 days with D+T (150/1 and 150/2, respectively). Of 365 pts who received D+T, 2 (<1%) cases of new cancers (colorectal and gliobastoma) and 2 (<1%) cases of new primary malignant melanoma were reported. Conclusions: These data support the experimental hypothesis that the occurrence of cuSCC (including KA) can be substantially reduced and delayed by the addition of a MEKi to BRAFi therapy. Clinical trial information: NCT01072175. [Table: see text]