Tebentafusp, A TCR/Anti-CD3 Bispecific Fusion Protein Targeting gp100, Potently Activated Antitumor Immune Responses in Patients with Metastatic Melanoma

PURPOSE

Tebentafusp is a first-in-class bispecific fusion protein designed to target gp100 (a melanoma-associated antigen) through a high affinity T-cell receptor (TCR) binding domain and an anti-CD3 T-cell engaging domain, which redirects T cells to kill gp100-expressing tumor cells. Here, we report a multicenter phase I/II trial of tebentafusp in metastatic melanoma (NCT01211262) focusing on the mechanism of action of tebentafusp.

PATIENTS AND METHODS

Eighty-four patients with advanced melanoma received tebentafusp. Treatment efficacy, treatment-related adverse events, and biomarker assessments were performed for blood-derived and tumor biopsy samples obtained at baseline and on-treatment.

RESULTS

Tebentafusp was generally well-tolerated and active in both patients with metastatic uveal melanoma and patients with metastatic cutaneous melanoma. A 1-year overall survival rate of 65% was achieved for both patient cohorts. On-treatment cytokine measurements were consistent with the induction of IFNγ pathway-related markers in the periphery and tumor. Notably, tebentafusp induced an increase in serum CXCL10 (a T-cell attractant) and a reduction in circulating CXCR3+ CD8+ T cells together with an increase in cytotoxic T cells in the tumor microenvironment. Furthermore, increased serum CXCL10 or the appearance of rash (likely due to cytotoxic T cells targeting gp100-expressing skin melanocytes) showed a positive association with patient survival.

CONCLUSIONS

These data suggest that redirecting T cells using a gp100-targeting TCR/anti-CD3 bispecific fusion protein may provide benefit to patients with metastatic melanoma. Furthermore, the activity observed in these two molecularly disparate melanoma classes hints at the broad therapeutic potential of tebentafusp.

Association between PD-L1 status and immune checkpoint inhibitor response in advanced malignancies: a systematic review and meta-analysis of overall survival data

BACKGROUND

Targeting the programmed death ligand 1 (PD-L1) pathway has become standard for many advanced malignancies. Whether PD-L1 expression predicts response is unclear. We assessed the association between PD-L1 expression and immunotherapy response using stratified meta-analysis.

METHODS

We performed a systematic review of randomized clinical trials published prior to October 2018 comparing overall survival (OS) in patients with advanced solid organ malignancies treated with immunotherapy or standard treatment. Pooled hazard ratios were calculated among patients with high and low PD-L1 levels independently. Differences between the two estimates were assessed using meta-analysis of study-level differences. Our primary analysis assessed a 1% threshold while secondary analyses utilized 5, 10 and 50%.

RESULTS

14 eligible trials reporting on 8887 patients were included. While there was a significant OS benefit for immunotherapy compared with standard treatment for all patients, the magnitude of benefit was significantly larger among those with high PD-L1 expression (P = 0.006). This finding persisted regardless of threshold used and across subgroup analyses according to PD-L1 assay type, tumor histology, line of therapy, type of inhibitor and study methodology.

CONCLUSIONS

PD-L1 levels have important predictive value in determining the response to immunotherapy. However, patients with low PD-L1 levels also experience improved survival with immunotherapy compared with standard treatment.

Mogamulizumab in Combination with Durvalumab or Tremelimumab in Patients with Advanced Solid Tumors: A Phase I Study

PURPOSE

The study goal was to determine safety, antitumor activity, and pharmacodynamic profile of mogamulizumab, an anti-C-C chemokine receptor 4 (anti-CCR4) mAb targeting effector regulatory T cells (eTreg), in combination with mAb checkpoint inhibitors durvalumab or tremelimumab.

PATIENTS AND METHODS

This was a multicenter, phase I, dose escalation study, followed by disease-specific cohort expansion (NCT02301130). Mogamulizumab dose escalation proceeded with concurrent dose escalation of durvalumab or tremelimumab in patients with advanced solid tumors. Cohort expansion occurred with mogamulizumab 1 mg/kg plus durvalumab 10 mg/kg or tremelimumab 10 mg/kg in patients with advanced pancreatic cancer.

RESULTS

Forty patients were enrolled during dose escalation, followed by 24 patients during dose expansion. No dose-limiting toxicities occurred during dose escalation. No new or unexpected toxicities were seen. Tolerability, the primary endpoint, was acceptable utilizing mogamulizumab 1 mg/kg plus durvalumab or tremelimumab 10 mg/kg in the combined dose escalation and dose expansion cohorts (each n = 19). At these doses, the objective response rate was 5.3% (95% confidence interval, 0.1%-26.0%; one partial response) with each combination treatment. At all doses, mogamulizumab treatment led to almost complete depletion of peripheral eTregs, as well as reduction of intratumoral Tregs in the majority of patients. There was no clear correlation of clinical response with peripheral or intratumoral reduction in CCR4⁺ eTregs or with baseline degree of CCR4⁺ expression.

CONCLUSIONS

Mogamulizumab in combination with durvalumab or tremelimumab did not result in potent antitumor efficacy in patients with advanced solid tumors. Tolerability of mogamulizumab 1 mg/kg combined with durvalumab or tremelimumab 10 mg/kg was acceptable.

Immune Checkpoint Inhibitors for Cancer Therapy in the COVID-19 Era

The potential immune intersection between COVID-19 disease and cancer therapy raises important practical clinical questions and highlights multiple scientific gaps to be filled. Among available therapeutic approaches to be considered, immune checkpoint inhibitors (ICI) seem to require major attention as they may act at the crossroads between cancer treatment and COVID-19 disease, due to their profound immunomodulatory activity. On the basis of available literature evidence, we suggest guidance to consider for treating physicians, and propose areas of clinical and preclinical investigation. Comprehensively, although with the necessary caution, ICI therapy seems to remain a suitable therapeutic option for patients with cancer during the COVID-19 pandemic.

Trial in progress: A phase I/II, open-label, dose-escalation, safety and tolerability study of NC318 in subjects with advanced or metastatic solid tumors

TPS3166

Background: Siglec-15 (S15) is a member of the Siglec family (Sialic acid-binding Immunoglobulin Lectins), a distinct subgroup of immunoglobulin (Ig) superfamily proteins involved in discriminating self from non-self-immune regulation (Macauley MS et al. 2014). Nonclinical models demonstrate S15 mediates suppression of T cell proliferation and negatively regulates T cell function. NC318 is a first-in-class monoclonal antibody that blocks S15-mediated immune suppression and prevents tumor growth by normalizing T cell function and restoring anti-tumor immunity in the tumor microenvironment (Wang J et al. 2019). The clinical hypothesis of this study is that NC318 targeting of S15 can improve anti-tumor immune response and provide benefit in multiple oncology indications. Methods: This is a multi-center, first in human, phase 1/2, open-label, non-randomized study to determine the safety and tolerability, define maximum tolerated dose and/or pharmacologically active dose, assess preliminary efficacy, and explore predictive and pharmacodynamic biomarkers of NC318 in subjects with advanced or metastatic solid tumors. Key eligibility criteria included measurable disease based on RECIST v1.1 and consent for collection of biopsies at screening and on treatment (optional for phase 1). Phase 1 used a 3+3 dose escalation design to determine the recommended phase 2 dose (RP2D) and schedule of NC318 while identifying drug related toxicities (DLTs). Phase 2 enrollment is limited to non-small cell lung, ovarian, head and neck, and triple negative breast cancer subjects with PD-L1 tumor proportion scores <50% (additional tumor types are being evaluated for inclusion). Ongoing exploratory analyses include the assessment of predictive biomarkers associated with treatment benefit, and pharmacodynamic markers associated with study drug activity (e.g. evaluation of tumor biopsies and peripheral markers of inflammation). Phase 1 enrollment began October 2018 and completed in August 2019. The RP2D was defined and the phase 2 opened to enrollment October 2019. Clinical trial information: NCT03665285 .

Long-term follow up of lifileucel (LN-144) cryopreserved autologous tumor infiltrating lymphocyte therapy in patients with advanced melanoma progressed on multiple prior therapies

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.

Final analysis of relapse-free survival in a multicenter, double-blind, placebo-controlled trial of seviprotimut-L polyvalent melanoma vaccine after resection of high-risk melanoma

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.

Long-term survival from pembrolizumab (pembro) completion and pembro retreatment: Phase III KEYNOTE-006 in advanced melanoma

10013

Background: 5-year follow-up of the phase 3 KEYNOTE-006 study (NCT01866319) showed pembro improved OS vs ipilimumab (ipi) in patients (pts) with advanced melanoma. 3-y OS rate from pembro completion for pts who completed 2 y of pembro was 93.8%. Results with 8 mo of additional follow-up are presented to inform clinical care. Methods: Eligible pts with ipi-naive advanced melanoma, ≤1 prior therapy for BRAF-mutant disease, and ECOG PS 0 or 1 were randomized to pembro 10 mg/kg Q2W or Q3W for ≤2 y or ipi 3 mg/kg Q3W for 4 doses. Pts discontinuing pembro with CR, PR, or SD after ≥94 weeks were considered pts with 2-y pembro. Pts who stopped pembro with SD, PR or CR could receive ≤12 mo of additional pembro (2nd course) upon disease progression if still eligible. ORR was assessed per immune-related response criteria by investigator review. OS was estimated using the Kaplan-Meier method. Pembro arm data were pooled. Post hoc ITT efficacy analyses are shown. Results: Median follow-up from randomization to data cutoff (Jul 31, 2019) was 66.7 mo in the pembro and 66.9 mo in the ipi arms. OS outcomes are shown in Table. For the 103 pts with 2-y pembro (30 CR, 63 PR, 10 SD), median follow-up from completion was 42.9 mo (95% CI, 39.9-46.3).Median DOR was not reached. 36-mo OS from pembro completion was 100% (95% CI, 100.0-100.0) for pts with CR, 94.8% (95% CI, 84.7-98.3) for pts with PR, and 66.7% (95% CI, 28.2-87.8) for pts with SD. 15 pts received 2nd-course pembro; BOR in 1st course was 6 CR, 6 PR, and 3 SD. Median time from end of 1st course to start of 2ndcourse was 24.5 mo (range, 4.9-41.4). Median follow-up in pts who received 2nd-course pembro was 25.3 mo (range, 3.5-39.4). Median duration of 2nd-course pembro was 8.3 mo (range, 1.4-12.6). BOR on 2ndcourse was 3 CR, 5 PR (ongoing responses, 7 pts), 3 SD (ongoing, 2 pts), and 2 PD (1 death); 2 pts pending. Conclusions: Pembro improves the long-term survival vs ipi in pts with advanced melanoma, with all pts who completed therapy in CR still alive at 5 years. Retreatment with pembro at progression in pts who stopped at SD or better can provide additional clinical benefit in a majority of pts. Clinical trial information: NCT01866319. [Table: see text]

Olaparib (O) in patients (pts) with pancreatic cancer with BRCA1/2 inactivating mutations: Results from the Targeted Agent and Profiling Utilization Registry (TAPUR) study

4637

Background: TAPUR is a phase II basket study evaluating anti-tumor activity of commercially available targeted agents in pts with advanced cancers with genomic alterations. Results in a cohort of pancreatic cancer pts with germline or somatic BRCA1/2 inactivating mutations treated with O are reported. Methods: Eligible pts had advanced pancreatic cancer, no standard treatment (tx) options available, measurable disease, ECOG Performance Status (PS) 0-2, and adequate organ function. Genomic testing was performed in CLIA-certified, CAP-accredited site selected labs. Pts received O tablets or capsules dosed at 300 mg (n=27) or 400 mg (n=3), respectively, orally twice daily until disease progression. Simon 2-stage design tested the null disease control (DC) (objective response (OR) or stable disease at 16+ weeks (wks) (SD16+) according to RECIST) rate of 15% vs. 35% (power = 0.85; α = 0.10). If ≥2 of 10 pts in stage 1 have DC, 18 more pts are enrolled. If ≥7 of 28 pts have DC, the tx is worthy of further study. Secondary endpoints are progression-free survival (PFS), overall survival (OS), and safety. Results: Thirty pts with BRCA1/2 inactivating mutations were enrolled from Nov 2016 to Aug 2019; 20 were previously treated with platinum based therapy. Two were not evaluable and excluded from efficacy analyses. Demographics and outcomes are summarized in Table. One partial response (PR) and 7 SD16+ were observed for DC and OR rates of 31% (90% CI: 18% - 40%) and 4% (95% CI: 0% - 18%), respectively. Seven pts had at least one grade 3 AE or SAE at least possibly related to O including anemia, diarrhea, fever, elevated liver enzymes, enterocolitis, increased bilirubin, and oral mucositis. Conclusions: Monotherapy O showed anti-tumor activity in heavily pre-treated pts with pancreatic cancer with germline (5/12 pts with OR or SD16+) or somatic (3/16 pts with OR or SD16+) BRCA1/2 inactivating mutations extending findings of recent studies of O in pts with advanced pancreatic cancer. Clinical trial information: NCT02693535 . [Table: see text]

Avelumab in patients with previously treated metastatic Merkel cell carcinoma: long-term data and biomarker analyses from the single-arm phase 2 JAVELIN Merkel 200 trial

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer associated with a high risk of metastasis. In 2017, avelumab (anti-programmed death-ligand 1 (PD-L1)) became the first approved treatment for patients with metastatic MCC (mMCC), based on the occurrence of durable responses in a subset of patients. Here, we report long-term efficacy and safety data and exploratory biomarker analyses in patients with mMCC treated with avelumab.

METHODS

In a cohort of this single-arm, phase 2 trial (JAVELIN Merkel 200), patients with mMCC and disease progression after prior chemotherapy received avelumab 10 mg/kg intravenously every 2 weeks. The primary endpoint was confirmed objective response rate (ORR) by independent review per Response Evaluation Criteria in Solid Tumors V.1.1. Other assessments included duration of response, progression-free survival, overall survival (OS), safety and biomarker analyses.

RESULTS

As of 14 September 2018, 88 patients had been followed up for a median of 40.8 months (range 36.4-49.7 months). The ORR was 33.0% (95% CI 23.3% to 43.8%), including a complete response in 11.4% (10 patients), and the median duration of response was 40.5 months (95% CI 18.0 months to not estimable). As of 2 May 2019 (≥44 months of follow-up), the median OS was 12.6 months (95% CI 7.5 to 17.1 months) and the 42-month OS rate was 31% (95% CI 22% to 41%). Of long-term survivors (OS >36 months) evaluable for PD-L1 expression status (n=22), 81.8% had PD-L1+ tumors. In exploratory biomarker analyses, high tumor mutational burden (≥2 non-synonymous somatic variants per megabase) and high major histocompatibility complex class I expression (30% of tumors with highest expression) were associated with trends for improved ORR and OS. In long-term safety assessments (≥36 months of follow-up), no new or unexpected adverse events were reported, and no treatment-related deaths occurred.

CONCLUSIONS

Avelumab showed continued durable responses and meaningful long-term survival outcomes in patients with mMCC, reinforcing avelumab as a standard-of-care treatment option for this disease.

TRIAL REGISTRATION NUMBER

NCT02155647.

The Great Debate at "Melanoma Bridge", Naples, December 7th, 2019

The Great Debate session at the 2019 Melanoma Bridge congress (December 5-7, Naples, Italy) featured counterpoint views from experts on five topical issues in melanoma. These were whether to choose local intratumoral treatment or systemic treatment, whether patients with stage IIIA melanoma require adjuvant therapy or not, whether treatment is better changed at disease progression or during stable disease, whether adoptive cell transfer (ACT) therapy is more appropriate used before or in combination with checkpoint inhibition therapy, and whether treatment can be stopped while the patient is still on response. As was the case for previous meetings, the debates were assigned by meeting Chairs. As such, positions taken by each of the melanoma experts during the debates may not have reflected their respective personal approach.

P860 Results from a combination of OX40 (PF-04518600) and 4–1BB (utomilumab) agonistic antibodies in melanoma and non-small cell lung cancer in a phase 1 dose expansion cohort

Background

PF-04518600 (PF-8600) and utomilumab (uto) are humanized agonist IgG2 monoclonal antibodies for the tumor necrosis factor superfamily receptors OX40 and 4-1BB, respectively. In a phase I dose escalation study (NCT02315066), this antibody combination was tolerable at all dose levels and induced responses in patients with melanoma resistant to immune checkpoint inhibitors. We report results from a dose expansion cohort of this study of patients with melanoma and non-small cell lung cancer (NSCLC) treated with PF-8600 (OX40 antibody) in combination with uto. Efficacy, safety, and the association of baseline and pharmacodynamic biomarkers with efficacy were examined.

Methods

In this expansion cohort, patients with locally advanced/metastatic melanoma (n=10) and NSCLC (n=20) who progressed on prior anti-PD1/PD-L1 treatment and/or anti CTLA4 treatment (melanoma only) were enrolled. Patients received OX40 antibody 30 mg IV every 2wks in combination with uto 20 mg IV every 28d. Tumor assessments were performed every 8wks using RECIST1.1. Paired biopsy samples collected at baseline and 6wks were analyzed by immunohistochemistry and RNA sequencing to evaluate the pharmacodynamic effects of the OX40 antibody in combination with uto. Whole blood samples were collected longitudinally, from which DNA was extracted and submitted for high-throughput sequencing of the T cell receptor β-chain.

Results

One patient with NSCLC achieved a confirmed and ongoing partial response lasting at least 6 months; Based on analyses of a subset of baseline biopsies, this patient’s tumor had the lowest FOXP3 expression. A total of 7 (70%) melanoma patients and 7 (35%) NSCLC patients achieved a best overall response of stable disease (SD). The median duration of SD was 16.3 weeks (melanoma: 16.0 weeks; NSCLC: 24.1 weeks), for a disease control rate of 50%. Among patients with a defined response, paired biopsy analyses showed that the greatest increase in CD8 occurred in the NSCLC patient with the longest duration of stable disease. The most frequent treatment related adverse events (TRAEs) reported in ≥10% of patients were pruritis, anemia, fatigue, decreased appetite, and rash. Grade 3 TRAEs, rash and lymphocyte count decreased, were reported in 5 patients and a grade 4 TRAE of lipase increased (asymptomatic) was reported in 1 patient.

Conclusions

The combination of PF-8600 and uto had a tolerable safety profile and demonstrated clinical benefit, including in an NSCLC patient who had progressed on anti-PD1 therapy and achieved a durable partial response. Further combinations with one or both of these immune costimulatory receptor agonist antibodies might enhance their efficacy.

Acknowledgements

This study was funded by Pfizer Inc. Editorial support was provided by Chu Kong Liew, PhD, of Engage Scientific Solutions and was funded by Pfizer Inc.

Trial Registration

ClinicalTrials. gov: NCT02315066

Ethics Approval

The study was approved by the institutional review board at each study center and conducted in accordance with the ethical principles of the Declaration of Helsinki.

The association between facility volume and overall survival in patients with Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma is an uncommon malignancy often requiring multidisciplinary management. The purpose of this study was to determine whether high-volume facilities have improved outcomes in patients with Merkel cell carcinoma relative to lower-volume facilities.

METHODS

A total of 5304 patients from the National Cancer Database with stage I-III Merkel cell carcinoma undergoing surgery were analyzed. High-volume facilities were the top 1% by case volume. Multivariable Cox regression and propensity score-matching were performed to account for imbalances between groups.

RESULTS

Treatment at high-volume facilities (hazard ratio: 0.74; 95% confidence interval: 0.65-0.84, P < .001) was independently associated with improved overall survival (OS) in multivariable analyses. In propensity score-matched cohorts, 5-year OS was 62.3% at high-volume facilities vs 56.8% at lower-volume facilities (P < .001). Median OS was 111 months at high-volume facilities vs 79 months at lower-volume facilities.

CONCLUSION

Treatment at high-volume facilities is associated with improved OS in Merkel cell carcinoma. Given the impracticality of referring all elderly patients with Merkel cell carcinoma to a small number of facilities, methods to mitigate this disparity should be explored.

Phase III Study of Adjuvant Ipilimumab (3 or 10 mg/kg) Versus High-Dose Interferon Alfa-2b for Resected High-Risk Melanoma: North American Intergroup E1609

PURPOSE

Phase III adjuvant trials have reported significant benefits in both relapse-free survival (RFS) and overall survival (OS) for high-dose interferon alfa (HDI) and ipilimumab at 10 mg/kg (ipi10). E1609 evaluated the safety and efficacy of ipilimumab at 3 mg/kg (ipi3) and ipi10 versus HDI.

PATIENTS AND METHODS

E1609 was a phase III trial in patients with resected cutaneous melanoma (American Joint Committee on Cancer 7th edition stage IIIB, IIIC, M1a, or M1b). It had 2 coprimary end points: OS and RFS. A 2-step hierarchic approach first evaluated ipi3 versus HDI followed by ipi10 versus HDI.

RESULTS

Between May 2011 and August 2014, 1,670 adult patients were centrally randomly assigned (1:1:1) to ipi3 (n = 523), HDI (n = 636), or ipi10 (n = 511). Treatment-related adverse events grade ≥ 3 occurred in 37% of patients receiving ipi3, 79% receiving HDI, and 58% receiving ipi10, with adverse events leading to treatment discontinuation in 35%, 20%, and 54%, respectively. Comparison of ipi3 versus HDI used an intent-to-treat analysis of concurrently randomly assigned patient cases (n = 1,051) and showed significant OS difference in favor of ipi3 (hazard ratio [HR], 0.78; 95.6% repeated CI, 0.61 to 0.99; P = .044; RFS: HR, 0.85; 99.4% CI, 0.66 to 1.09; P = .065). In the second step, for ipi10 versus HDI (n = 989), trends in favor of ipi10 did not achieve statistical significance. Salvage patterns after melanoma relapse showed significantly higher rates of ipilimumab and ipilimumab/anti-programmed death 1 use in the HDI arm versus ipi3 and ipi10 (P ≤ .001).

CONCLUSION

Adjuvant therapy with ipi3 benefits survival versus HDI; for the first time to our knowledge in melanoma adjuvant therapy, E1609 has demonstrated a significant improvement in OS against an active control regimen. The currently approved adjuvant ipilimumab dose (ipi10) was more toxic and not superior in efficacy to HDI.

Association of Patient Sex With Efficacy of Immune Checkpoint Inhibitors and Overall Survival in Advanced Cancers: A Systematic Review and Meta-analysis

Importance

Sex-associated differences in immune response are known, but a meta-analysis suggested men, compared with women, derive greater value from immunotherapy for advanced solid-organ malignant neoplasms. However, methodologic concerns and subsequent trials have placed these results in doubt.

Objective

To perform an updated, comprehensive meta-analysis that assesses the efficacy of immunotherapy in advanced cancers according to patient sex.

Design, Setting, and Participants

A systematic review of studies (n = 23) indexed in MEDLINE (PubMed), Embase, and Scopus from inception of these databases to October 2, 2018, was conducted. Randomized clinical trials that compared immunotherapy with standard of care in the treatment of advanced solid-organ malignant neoplasms were included if overall survival was reported as an outcome and if data stratified by patient sex were available. Observational studies, editorials, commentaries, review articles, non-peer-reviewed publications, studies that compared various immunotherapy regimens, studies that reported other measures of oncologic response, and studies that reported subgroup analyses for 1 sex only were excluded.

Main Outcomes and Measures

Overall survival, with a test for heterogeneity between women and men, to assess the null hypothesis that no difference in the survival advantage of immunotherapy exists by patient sex.

Results

This meta-analysis included 23 randomized clinical trials that reported on 9322 men (67.9%) and 4399 women (32.1%); the age of most patients was in the 70s. An overall survival benefit of immunotherapy was found for both men (hazard ratio [HR], 0.75; 95% CI, 0.69-0.81; P < .001) and women (HR, 0.77; 95% CI, 0.67-0.88; P = .002). Random-effects meta-analysis of study-level differences in response to immunotherapy demonstrated no statistically significant difference between the sexes (I2 = 38%; P = .60). Subgroup analyses according to disease site, line of therapy, class of immunotherapy, study methodology, and representation of women recapitulated these findings.

Conclusions and Relevance

Stratified analyses demonstrated no statistically significant association of patient sex with the efficacy of immunotherapy in the treatment of advanced cancers using overall survival as the outcome.

Analysis of OX40 agonist antibody (PF-04518600) in patients with hepatocellular carcinoma

523

Background: PF-04518600 (PF-8600) is a humanized agonist IgG2 monoclonal antibody to the tumor necrosis factor superfamily receptor OX40. PF-8600 was given to patients (pts) with advanced/metastatic hepatocellular carcinoma (HCC) in dose expansion of a phase 1 study (NCT02315066). Safety and tolerability were primary endpoints and exploratory endpoints included biomarker analyses. Methods: Pts received either 30 mg (Arm 1) or 250 mg (Arm 2) of PF-8600 intravenously Q2W. Pts had pathologic diagnosis of advanced HCC, a Child-Pugh score of A or B7, and had ≤2 prior lines of therapy, or if treatment naïve, had declined standard of care. Radiological tumor assessments were conducted Q8W. Biopsy samples collected at baseline and wk 6 were analyzed by immunohistochemistry and RNA sequencing for pharmacodynamic (PD) analyses. Whole blood samples were collected longitudinally for DNA extraction for high-throughput sequencing of the T cell receptor β-chain. Results: Arm 1 enrolled 16 pts (mean age 65.6 yrs; range 54-81 yrs; prior PD-1/PD-L1: 5 pts) and Arm 2 enrolled 19 pts (mean age 61.7 yrs; range 26-79 yrs; prior PD-1/PD-L1: 3 pts). All grade treatment related adverse events (TRAEs) occurred in 69% of pts in Arm 1 and 58% of pts in Arm 2. The rate of ≥Grade 3 TRAEs was 31% and 16% in Arms 1 and 2, respectively. For both arms combined, the most common (≥10%) TRAEs were rashes and pruritus. In Arm 1, 8 pts (50%) and in Arm 2, 10 pts (53%) achieved stable disease (SD), with a mean duration of 18.4 (range: 14.0-30.3 wks) and 17.4 wks (range: 8.0-31.9 wks), respectively. PD effects were more evident in Arm 1 than Arm 2, including increased OX40 tumor expression and positive changes in gene signatures, reflecting an active anti-tumor immune response. Conclusions: PF-8600 was generally well tolerated and provided meaningful disease control. While safety and efficacy were not significantly different between the 2 doses, there were potential differences in the PD data. The safety and relative durability of SD in HCC pts may provide a rationale for exploration of combination therapy in this pt population. Clinical trial information: NCT02315066.

Quantitative metastatic lymph node burden and survival in Merkel cell carcinoma

BACKGROUND

Current lymph node (LN) staging for Merkel cell carcinoma (MCC) does not account for the number of metastatic LNs, which is a primary driver of survival in multiple cancers.

OBJECTIVE

To determine the impact of the number of metastatic LNs on survival in MCC.

METHODS

Patients with MCC undergoing surgery were identified from the National Cancer Database (NCDB). The association between metastatic LN number and survival was modeled with restricted cubic splines. A novel nodal classification system was derived by using recursive partitioning analysis. MCC patients undergoing surgery in the Surveillance, Epidemiology, and End Results (SEER) Program were used as validation cohort.

RESULTS

Among 3670 patients in the NCDB, increasing metastatic LN number was associated with decreased survival (P < .001). Mortality risk increased continuously with each additional positive LN when using multivariable, nonlinear modeling. According to a novel staging system derived via recursive partitioning analysis, the hazard ratio for death in multivariable regression compared with patients without LN involvement was 1.24 (P = .049), 2.08 (P < .001), 3.24 (P < .001), and 6.13 (P < .001) for the proposed N1a (1-3 metastatic LNs with microscopic detection), N1b (1-3 metastatic LNs with macroscopic detection), N2 (4-8 metastatic LNs), and N3 (≥9 metastatic LNs), respectively. This system was validated in the SEER cohort and showed improved concordance compared with the American Joint Committee on Cancer, Eighth Edition.

LIMITATIONS

Retrospective design.

CONCLUSIONS

Number of metastatic LNs is the dominant nodal factor driving survival in patients with MCC.

Treatment patterns of malignant melanoma in the United States from 2011 to 2016: a retrospective cohort study

Background: Since 2011, the approval of several new agents has improved treatment options for malignant melanoma. We describe treatment patterns for malignant melanoma in the United States from the MarketScan database from 2011 to 2016.Methods: Treatments used for patients aged >18 years diagnosed with malignant melanoma after January 1, 2011 and enrolled in the Truven MarketScan database were analyzed. Patient data were collected for the 12-month period from the date of the first melanoma diagnosis to either death, the pre-specified study end date (August 31, 2016), or date of termination of health insurance. Treatment patterns from 2011-2013 and 2014-2016 were analyzed according to agent, year of drug administration, and line of therapy.Results: From 2011 to 2016, use of cytokines (63.8; 13.3%) and chemotherapy (19.6; 12.9%) decreased, and use of checkpoint inhibitors increased (2.0; 49.9%). Checkpoint inhibitor use also increased across all lines of therapy from 2011-2013 and 2014-2016. Use of BRAF/MEK inhibitors remained relatively stable from 2011 to 2016 (6.5-12.5%); however, the use of vemurafenib monotherapy decreased (6.5; 0.8%), and treatment with combination regimens increased (0; 10.9%) from 2011-2016. BRAF/MEK inhibitor use only increased in the first line setting from 2011-2013 (9.7%) to 2014-2016 (11.2%).Conclusion: With the approval of immune checkpoint inhibitors, BRAF/MEK inhibitors, and targeted therapies, the therapeutic landscape for the treatment of metastatic melanoma has shifted dramatically away from cytokines and chemotherapy. Treatment patterns will likely continue to evolve as scientific advances are made.

Intratumoral Immunotherapy-Update 2019

Intratumoral immunotherapies aim to trigger local and systemic immunologic responses via direct injection of immunostimulatory agents with the goal of tumor cell lysis, followed by release of tumor‐derived antigens and subsequent activation of tumor‐specific effector T cells. In 2019, a multitude of intratumoral immunotherapies with varied mechanisms of action, including nononcolytic viral therapies such as PV‐10 and toll‐like receptor 9 agonists and oncolytic viral therapies such as CAVATAK, Pexa‐Vec, and HF10, have been extensively evaluated in clinical trials and demonstrated promising antitumor activity with tolerable toxicities in melanoma and other solid tumor types. Talimogene laherparepvec (T‐VEC), a genetically modified herpes simplex virus type 1–based oncolytic immunotherapy, is the first oncolytic virus approved by the U.S. Food and Drug Administration for the treatment of unresectable melanoma recurrent after initial surgery. In patients with unresectable metastatic melanoma, T‐VEC demonstrated a superior durable response rate (continuous complete response or partial response lasting ≥6 months) over subcutaneous GM‐CSF (16.3% vs. 2.1%; p < .001). Responses were seen in both injected and uninjected lesions including visceral lesions, suggesting a systemic antitumor response. When combined with immune checkpoint inhibitors, T‐VEC significantly improved response rates compared with single agent; similar results were seen with combinations of checkpoint inhibitors and other intratumoral therapies such as CAVATAK, HF10, and TLR9 agonists. In this review, we highlight recent results from clinical trials of key intratumoral immunotherapies that are being evaluated in the clinic, with a focus on T‐VEC in the treatment of advanced melanoma as a model for future solid tumor indications.

Implications for Practice

This review provides oncologists with the latest information on the development of key intratumoral immunotherapies, particularly oncolytic viruses. Currently, T‐VEC is the only U.S. Food and Drug Administration (FDA)‐approved oncolytic immunotherapy. This article highlights the efficacy and safety data from clinical trials of T‐VEC both as monotherapy and in combination with immune checkpoint inhibitors. This review summarizes current knowledge on intratumoral therapies, a novel modality with increased utility in cancer treatment, and T‐VEC, the only U.S. FDA‐approved oncolytic viral therapy, for medical oncologists. This review evaluates approaches to incorporate T‐VEC into daily practice to offer the possibility of response in selected melanoma patients with manageable adverse events as compared with other available immunotherapies.

This review highlights recent results from clinical trials of key intratumoral immunotherapies that are being evaluated in the clinic, with a focus on talimogene laherparepvec in the treatment of advanced melanoma as a model for future solid tumor indications.

Extended 5-Year Follow-up Results of a Phase Ib Study (BRIM7) of Vemurafenib and Cobimetinib in BRAF-Mutant Melanoma

PURPOSE

To report the 5-year overall survival (OS) landmark and the long-term safety profile of vemurafenib plus cobimetinib (BRAF plus MEK inhibition, respectively) in the BRIM7 study.

PATIENTS AND METHODS

This phase Ib, dose-finding, and expansion study evaluated combination treatment with vemurafenib and cobimetinib in two cohorts of patients with advanced BRAF ^V600-mutated melanoma: patients who were BRAF inhibitor (BRAFi)-naïve (n = 63) or patients who had progressed on prior treatment with BRAFi monotherapy [vemurafenib monotherapy-progressive disease (PD); n = 66]. Patients in the dose-escalation phase received vemurafenib at 720 or 960 mg twice daily in combination with cobimetinib at 60, 80, or 100 mg/d for 14 days on/14 days off, 21 days on/7 days off, or continuously. Two regimens were selected for expansion: vemurafenib (720 and 960 mg twice daily) and cobimetinib (60 mg/d 21/7).

RESULTS

Median OS was 31.8 months [95% confidence interval (CI), 24.5-not estimable] in the BRAFi-naïve cohort. The landmark OS rate plateaued at 39.2% at years 4 and 5 of follow-up. In the vemurafenib monotherapy-PD cohort, the median OS was 8.5 months (95% CI, 6.7-11.1), and the landmark OS rate plateaued at 14.0% from 3 years of follow-up. No increase was observed in the frequency and severity of adverse events with long-term follow-up. No new toxicities were detected, and there was no increase in the frequency of symptomatic MEK inhibitor class-effect adverse events.

CONCLUSIONS

A subset of patients with advanced BRAF ^V600-mutated melanoma treated with a combination regimen of vemurafenib and cobimetinib achieve favorable long-term outcomes.

Treatment patterns of melanoma by BRAF mutation status in the USA from 2011 to 2017: a retrospective cohort study

AIM

To describe treatment changes from 2011 to 2017 and demographic/clinical characteristics of patients with advanced melanoma who received systemic therapy by BRAF status.

PATIENTS & METHODS

Treatment patterns were evaluated in adults from the Oncology Services Comprehensive Electronic Records database who received antimelanoma systemic therapy.

RESULTS

Checkpoint inhibitors were prevailingly prescribed (66%); usage increased from 2011 (21%) to 2017 (84%). BRAF/MEK inhibitors were the second most common (21%); usage increased from 2011 (6%) to 2012 (18%) and stabilized until 2017 (22%). BRAF/MEK inhibitors (65%) and checkpoint inhibitors (57%) were predominantly used for BRAFMut melanoma.

CONCLUSION

Overall, checkpoint inhibitors have supplanted other therapies for advanced melanoma. Treatment shifts have occurred for BRAFMut melanoma, notably increased use of checkpoint inhibitors and BRAF/MEK combinations compared with monotherapies.

Efficacy, Safety, and Tolerability of Approved Combination BRAF and MEK Inhibitor Regimens for BRAF-Mutant Melanoma

No head-to-head studies exist comparing BRAF inhibitor/MEK inhibitor (BRAFi/MEKi) combination treatments for BRAF-mutant melanoma. A side-by-side analysis of randomized phase III trials is presented that evaluated dabrafenib/trametinib, vemurafenib/cobimetinib, and encorafenib/binimetinib. The baseline characteristics, efficacy, and safety were compared: COMBI-v (dabrafenib/trametinib versus vemurafenib); coBRIM (vemurafenib/cobimetinib versus vemurafenib); and COLUMBUS (encorafenib/binimetinib versus encorafenib and vemurafenib). Vemurafenib was the control arm in all studies. The data sources included literature databases, European public assessment reports, U.S. Food and Drug Administration review documents, and prescribing information. The baseline characteristics were similar, except for coBRIM, which had a higher proportion of patients with elevated lactate dehydrogenase (LDH) levels. The median progression-free survival (PFS) and overall response rate (ORR) were similar across the trials, although numerically higher values were observed with encorafenib/binimetinib. In contrast, the median overall survival (OS) was numerically longer with encorafenib/binimetinib (33.6 months) compared to dabrafenib/trametinib (25.6 months) and vemurafenib/cobimetinib (22.3 months). Among vemurafenib arms, PFS, ORR, and OS were similar, despite variations in the baseline LDH. Each combination displayed a unique safety profile, with higher incidences of pyrexia with dabrafenib/trametinib and photosensitivity reactions with vemurafenib/cobimetinib. This analysis of BRAFi/MEKi combinations for BRAF-mutant melanoma, while limited as not a direct head-to-head clinical trial, highlights the differences in tolerability and efficacy that may be useful for therapeutic decision making.