Pembrolizumab versus ipilimumab for advanced melanoma: final overall survival results of a multicentre, randomised, open-label phase 3 study (KEYNOTE-006)

BACKGROUND

Interim analyses of the phase 3 KEYNOTE-006 study showed superior overall and progression-free survival of pembrolizumab versus ipilimumab in patients with advanced melanoma. We present the final protocol-specified survival analysis.

METHODS

In this multicentre, open-label, randomised, phase 3 trial, we recruited patients from 87 academic institutions, hospitals, and cancer centres in 16 countries (Australia, Austria, Belgium, Canada, Chile, Colombia, France, Germany, Israel, Netherlands, New Zealand, Norway, Spain, Sweden, UK, and USA). We randomly assigned participants (1:1:1) to one of two dose regimens of pembrolizumab, or one regimen of ipilimumab, using a centralised, computer-generated allocation schedule. Treatment assignments used blocked randomisation within strata. Eligible patients were at least 18 years old, with an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, at least one measurable lesion per Response Evaluation Criteria In Solid Tumors version 1.1 (RECIST v1.1), unresectable stage III or IV melanoma (excluding ocular melanoma), and up to one previous systemic therapy (excluding anti-CTLA-4, PD-1, or PD-L1 agents). Secondary eligibility criteria are described later. Patients were excluded if they had active brain metastases or active autoimmune disease requiring systemic steroids. The primary outcome was overall survival (defined as the time from randomisation to death from any cause). Response was assessed per RECIST v1.1 by independent central review at week 12, then every 6 weeks up to week 48, and then every 12 weeks thereafter. Survival was assessed every 12 weeks, and final analysis occurred after all patients were followed up for at least 21 months. Primary analysis was done on the intention-to-treat population (all randomly assigned patients) and safety analyses were done in the treated population (all randomly assigned patients who received at least one dose of study treatment). Data cutoff date for this analysis was Dec 3, 2015. This study was registered with ClinicalTrials.gov, number NCT01866319.

FINDINGS

Between Sept 18, 2013, and March 3, 2014, 834 patients with advanced melanoma were enrolled and randomly assigned to receive intravenous pembrolizumab every 2 weeks (n=279), intravenous pembrolizumab every 3 weeks (n=277), or intravenous ipilimumab every 3 weeks (ipilimumab for four doses; n=278). One patient in the pembrolizumab 2 week group and 22 patients in the ipilimumab group withdrew consent and did not receive treatment. A total of 811 patients received at least one dose of study treatment. Median follow-up was 22·9 months; 383 patients died. Median overall survival was not reached in either pembrolizumab group and was 16·0 months with ipilimumab (hazard ratio [HR] 0·68, 95% CI 0·53-0·87 for pembrolizumab every 2 weeks vs ipilimumab; p=0·0009 and 0·68, 0·53-0·86 for pembrolizumab every 3 weeks vs ipilimumab; p=0·0008). 24-month overall survival rate was 55% in the 2-week group, 55% in the 3-week group, and 43% in the ipilimumab group.

INTERPRETATION

Substantiating the results of the interim analyses of KEYNOTE-006, pembrolizumab continued to provide superior overall survival versus ipilimumab, with no difference between pembrolizumab dosing schedules. These conclusions further support the use of pembrolizumab as a standard of care for advanced melanoma.

FUNDING

Merck & Co.

Phase II randomised discontinuation trial of cabozantinib in patients with advanced solid tumours

BACKGROUND

Cabozantinib is an inhibitor of tyrosine kinases, including MET, vascular endothelial growth factor receptor, AXL and RET. This multi-cohort phase II randomised discontinuation trial explored anticancer activity of cabozantinib in nine tumour types.

PATIENTS AND METHODS

Cabozantinib was administered (100 mg, once daily) to patients with advanced, recurrent or metastatic cancers. Those with stable disease at week 12 were randomised 1:1 to cabozantinib or placebo. Primary end-points were objective response rate (ORR) at week 12 and progression-free survival (PFS) in the randomised phase.

RESULTS

A total of 526 patients were enrolled. The highest ORR was observed in ovarian cancer (OC) (21.7%); the largest PFS benefit was observed in castration-resistant prostate cancer (CRPC) (median 5.5 versus 1.4 months for placebo; hazard ratio 0.14, 95% confidence interval: 0.04, 0.52). Disease control rates were >40% for CRPC, OC, melanoma, metastatic breast cancer (MBC), hepatocellular carcinoma (HCC) and non-small cell lung cancer. Median duration of response ranged from 3.3 (MBC) to 11.2 months (OC). Encouraging efficacy results and symptomatic improvements prompted early suspension of the randomised stage and conversion to open-label non-randomised expansion cohorts. Dose reductions to manage adverse events (AEs) occurred in 48.7% of patients. The most frequent grade III-IV AEs were fatigue (12.4%), diarrhoea (10.5%), hypertension (10.5%) and palmar-plantar erythrodysesthesia syndrome (8.7%).

CONCLUSIONS

Clinical antitumour activity of cabozantinib was observed in a subset of tumour types: CRPC and OC were evaluated further in expansion cohorts. Phase III programs were initiated in CRPC and HCC. Interpretation of efficacy outcomes was limited by early termination of the randomised portion of the trial.

TRIAL REGISTRATION NUMBER

NCT00940225.

Overall Survival in Patients With Advanced Melanoma Who Received Nivolumab Versus Investigator's Choice Chemotherapy in CheckMate 037: A Randomized, Controlled, Open-Label Phase III Trial

Purpose Until recently, limited options existed for patients with advanced melanoma who experienced disease progression while receiving treatment with ipilimumab. Here, we report the coprimary overall survival (OS) end point of CheckMate 037, which has previously shown that nivolumab resulted in more patients achieving an objective response compared with chemotherapy regimens in ipilimumab-refractory patients with advanced melanoma. Patients and Methods Patients were stratified by programmed death-ligand 1 expression, BRAF status, and best prior cytotoxic T-lymphocyte antigen-4 therapy response, then randomly assigned 2:1 to nivolumab 3 mg/kg intravenously every 2 weeks or investigator's choice chemotherapy (ICC; dacarbazine 1,000 mg/m² every 3 weeks or carboplatin area under the curve 6 plus paclitaxel 175 mg/m² every 3 weeks). Patients were treated until they experienced progression or unacceptable toxicity, with follow-up of approximately 2 years. Results Two hundred seventy-two patients were randomly assigned to nivolumab (99% treated) and 133 to ICC (77% treated). More nivolumab-treated patients had brain metastases (20% v 14%) and increased lactate dehydrogenase levels (52% v 38%) at baseline; 41% of patients treated with ICC versus 11% of patients treated with nivolumab received anti-programmed death 1 agents after randomly assigned therapy. Median OS was 16 months for nivolumab versus 14 months for ICC (hazard ratio, 0.95; 95.54% CI, 0.73 to 1.24); median progression-free survival was 3.1 months versus 3.7 months, respectively (hazard ratio, 1.0; 95.1% CI, 0.78 to 1.436). Overall response rate (27% v 10%) and median duration of response (32 months v 13 months) were notably higher for nivolumab versus ICC. Fewer grade 3 and 4 treatment-related adverse events were observed in patients on nivolumab (14% v 34%). Conclusion Nivolumab demonstrated higher, more durable responses but no difference in survival compared with ICC. OS should be interpreted with caution as it was likely impacted by an increased dropout rate before treatment, which led to crossover therapy in the ICC group, and by an increased proportion of patients in the nivolumab group with poor prognostic factors.

Abstract 683A: Mechanism of liver metastasis induced systemic suppression of checkpoint inhibitor response

Introduction: In stage IV melanoma and NSCLC, PD-1 checkpoint inhibitor therapy is effective and now FDA approved as first-line therapy. However, despite these rationally designed strategies to manipulate immune cells, curative responses remain rare, and the majority of metastatic cancer patients ultimately succumb to their disease. Emerging potential biomarkers of response have required specialized technologies such as next-generation sequencing or flow cytometry, which are difficult to access, costly, and not immediately clinically applicable. To this end, we have previously reported that presence of liver metastasis was significantly associated with the lack of antitumor immune infiltrates at distant biopsy sites as well as poor clinical response to PD-1 blockade. Here, we sought to study the mechanism of liver metastasis related non-response to PD-1 blockade using a syngeneic immunocompetent murine tumor model.

Methods: C57BL/6 mice were implanted with a "primary” subcutaneous tumor as well as a secondary “metastatic” tumor in the liver or the lungs (control), and given systemic PD-1 blockade therapy to mimic the clinical observation and study the effects of liver tumor involvement on systemic antitumor immunity. Animals are monitored for survival and tumor growth. The immune infiltrates of both the primary and metastatic sites are phenotypically analyzed.

Results: Animals with liver tumor involvement appear to have significantly shortened survival as well as difficulty rejecting tumors, both at the primary and secondary site of implantation, when compared to non-liver involved controls. The lack of response to PD-1 blockade in the liver cohort is correlated with a significant decrease in CTLA4+/PD-1+/CD8+ “exhausted” antigen experienced T cells (TEx) within the tumor microenvironment of the subcutaneous and liver-embedded sites. The deleterious effect on TEx appears to be liver-specific and not tumor cell-line dependent, as delivery of different tumor cells to the liver reproduces the same effect while delivery of tumor cells to other organs does not change the quantity of TEx at the subcutaneous site. Lastly, liver associated deletion of TEx appears to be a an antigen dependent process, as delivery of mismatched tumor cell line to the liver abrogates this effect and restores TEx within the tumor microenvironment at the distant subcutaneous site.

Conclusions: Using an immunocompetent checkpoint blockade animal tumor model, we recapitulated the clinically observed difference in response to PD-1 blockade treatment that is associated with liver metastasis. Our studies suggest that the liver is capable of suppressing effective T cell mediated antitumor response systemically, rendering checkpoint blockade less effective. The findings here propose a novel mechanism for which non-responsiveness to PD-1 blockade therapy could occur and may impact the treatment decision for cancer patients with liver metastasis.

Citation Format: James C. Lee, Adil Daud, Jeff Bluestone. Mechanism of liver metastasis induced systemic suppression of checkpoint inhibitor response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 683A. doi:10.1158/1538-7445.AM2017-683A

Long-term outcomes in patients (pts) with ipilimumab (ipi)-naive advanced melanoma in the phase 3 KEYNOTE-006 study who completed pembrolizumab (pembro) treatment

9504

Background: Pembro demonstrated superior PFS and OS vs ipi in ipi-naive pts with advanced melanoma in the phase 3 KEYNOTE-006 study (NCT01866319). Here, we present long-term outcomes for all pts and in those pts who completed pembro therapy. Methods: Eligible pts (N = 834) were randomized 1:1:1 to pembro 10 mg/kg Q2W, pembro 10 mg/kg Q3W, or ipi 3 mg/kg Q3W for 4 doses. Treatment was continued for 2 yr (pembro only) or until disease progression, intolerable toxicity, or pt/investigator decision to discontinue. Per protocol, pts could interrupt pembro for ≤12 wk before discontinuation was required. Tumor imaging was performed at wk 12, then every 6 wk up to wk 48 and every 12 wk thereafter. After the prespecified final analysis, response assessments were per immune-related response criteria (irRC) by investigator review. Results: As of the data cutoff (Nov 3, 2016), median follow-up in the total population was 33.9 mo (range, 32.1-37.6). 33-mo OS rates were 50% in the pooled pembro arms (n = 556) and 39% in the ipi arm (n = 278); 33-mo PFS rates were 31% and 14%. ORR was 42% and 16%. Median duration of response was not reached for pembro (range 1.0+ to 33.8+ mo) or ipi (1.1+ to 34.8+ mo); 46 (68%) pembro-treated pts and 7 (58%) ipi-treated pts had a response lasting ≥30 mo. Among the 104/556 (19%) pts who completed pembro, median exposure to pembro was 24.0 mo (range 22.1-25.9). After a median follow-up of 9.0 mo after completion of pembro, 102 (98%) pts were alive. Responses were durable in pts who completed pembro; 9.7 mo after completion of pembro, estimated PFS (95% CI) was 91% (80-96) in all 104 pts, 95% (69-99) in pts with complete response (n = 24), 91% (74-97) in pts with partial response (n = 68), and 83% (48-96) in pts with stable disease (n = 12). Conclusions: Pembro provides durable efficacy after stopping the protocol-specified duration of treatment in pts with ipi-naive advanced melanoma in KEYNOTE-006. The estimated risk for progression or death nearly 10 mo after completing pembro is 9% and does not appear to differ by best response to pembro. Clinical trial information: NCT01866319.

Quantitative spatial profiling of PD-1/PD-L1 interaction and HLA-DR/IDO1 to predict outcomes to anti-PD-1 in metastatic melanoma (MM)

9517

Background: Although PD-1/L1 axis directed therapies induce durable responses in some mm patients (pts), biomarkers of response remain elusive. We hypothesized that quantifying key immune suppression mechanisms within the tumor microenvironment would provide superior predictors of response to anti-PD-1 compared with single marker assessment. Methods: Pre-treatment tumor biopsies from 124 mm pts treated with anti-PD-1 at 7 academic centers were fluorescently stained with multiple immune markers in discovery (n = 24) and validation (n = 100) cohorts. Selected biomarker signatures, PD-1/PD-L1 interaction score (proportion of PD-1+ cells co-localized with PD-L1) and IDO1/HLA-DR co-expression were evaluated for anti-PD-1 treatment response and survival. Slides were imaged using Vectra; biomarker positive cells and their co-localization were objectively quantified in pathologist-selected regions using novel Automated Quantitative Analysis (AQUA) algorithms. Results: In the discovery cohort, high levels of PD-1/PD-L1 interaction score and/or IDO1/HLA-DR coexpression was strongly positively associated with response to anti-PD-1 (p = 0.0005). In contrast, other individual biomarkers (PD-1, PD-L1, CD8) were not associated with response or survival (p > 0.10). This finding was replicated in the validation cohort: pts with high PD-1/PD-L1 and/or IDO1/HLA-DR were more likely to respond to treatment (p = 0.009). These pts also experienced a three-fold increase in progression free survival (hazards ratio (HR) = 0.33; p = 0.003) and overall survival (HR = 0.34; p = 0.004). Multivariate analyses revealed that these findings were independent of BRAF mutation, stage, LDH and prior therapy. In the combined cohort (n = 124), 80% of responding pts had higher levels of PD-1/PD-L1 interaction scores and/or IDO1/HLA-DR. In contrast, PD-L1 expression alone (≥1% or ≥50%) was not predictive of PFS or OS (p > 0.1). Conclusions: This novel multiplexed method profiling key tumor-immune suppression pathways identified mm pts likely to respond to anti-PD-1 therapy. This method could help stratify patients for PD-1 monotherapy and be useful in guiding future clinical trials.

Sexual activity and function in male cancer patients receiving targeted an immune therapies

e21594

Background: Survivorship concerns–including sexual function–move increasingly to the foreground in cancer patient care as systemic therapies improve response and survival. Patients are often committed to long-term treatment with tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICI) despite poor characterization of their effects on sexual function. We sought to assess sexual activity and function in patients receiving TKI or ICI. Methods: A cohort of men receiving TKI/ICI at the UCSF Helen Diller Family Comprehensive Cancer Center were retrospectively identified. Eligible men were on ongoing TKI/ICI therapy. Detailed questionnaires addressing cancer history, treatment history, and sexual activity/function while receiving therapy were completed. Results: Between January 2013 to September 2016, 51 men completed questionnaires. Mean age was 46 years (SD 12, range 21-72). Most (61%) were CML patients, with 12% RCC, 10% GIST, 6% melanoma, and NET, oligodendroglioma, and HCC comprising remaining histologies. 96% were treated with TKI, and 4% with ICI (pembrolizumab). 32% identified as being married or in a domestic partnership, and 18% identified as single. Only 14% reported no attempted sexual activity. Sexual desire was described as low or very low to none in 29%, average in 39%, and high or very high in 29%. Since cancer diagnosis, 21 (41%) of patients noted a reduced amount of semen upon ejaculation, and all but 5 of those patients noted this as at least somewhat bothersome. 35% of patients reported feeling at least somewhat distressed from sexual experiences since cancer diagnosis, including concern that their time to ejaculation may leave their partners feeling unfulfilled (45%), decreased sensation of orgasm (35%), difficulty maintaining erection until completion of intercourse (23%), and pain/discomfort upon ejaculation (12%). Conclusions: The majority of men on TKI or ICI remain sexually active, with a significant portion reporting sexual dysfunction. These findings highlight the need for oncology care providers to proactively manage sexual dysfunction to improve quality of life for cancer patients. Retrospective and prospective studies are ongoing to further characterize this cohort.

Epacadostat plus nivolumab in patients with advanced solid tumors: Preliminary phase I/II results of ECHO-204

3003

Background: ECHO-204 is an ongoing, open-label, phase 1/2 (P1/2) study of epacadostat (E; potent and selective oral inhibitor of the immunosuppressive enzyme indoleamine 2,3-dioxygenase 1) plus PD-1 inhibitor nivolumab (N) in patients (pts) with advanced cancers (NSCLC, MEL, OVC, CRC, SCCHN, B-cell NHL [including DLBCL], GBM). Preliminary P1/2 safety and tolerability outcomes for the overall study population and P2 response for select tumor types (SCCHN, MEL, OVC, CRC) are reported. Methods: In P1 dose escalation, pts received E (25, 50, 100, 300 mg BID) + N (3 mg/kg Q2W); in P2 cohort expansion, pts received E (100 or 300 mg BID) + N (240 mg Q2W). Safety/tolerability was assessed in pts receiving ≥1 E + N dose. Response was assessed in RECIST v1.1 evaluable pts; for recently enrolled pt subgroups, only preliminary DCR (CR+PR+SD) is presented. Results: As of 29OCT2016,241 pts (P1, n = 36; P2, n = 205) were enrolled. No DLT was observed in P1. Most common TRAEs (≥15%) in pts treated with E 100 mg (n = 70) and E 300 mg (n = 135) were rash (33% and 22%, respectively), fatigue (26% and 31%), and nausea (24% and 19%). Rash was the most common grade ≥3 TRAE in E 100 mg and E 300 mg subgroups (10% and 12%). TRAEs led to discontinuation in 7% (E 100 mg) and 13% (E 300 mg) of pts. There were no TR-deaths. For the 23 recently enrolled, efficacy-evaluable SCCHN pts treated with E 300 mg, preliminary DCR was 70% (n = 16). Of 30 MEL pts, 8 were treated with E 100 mg and 22 were more recently enrolled and treated with E 300 mg. ORR (CR+PR) and DCR in MEL pts treated with E 100 mg were 75% (n = 6; all PR) and 100% (n = 8; 2 SD), respectively. Preliminary DCR in MEL pts treated with E 300 mg was 64% (n = 14). Of 29 OVC pts, 18 were treated with E 100 mg and 11 with E 300 mg.ORR and DCR for OVC pts treated with E 100 mg were 11% (n = 2; 2 PR) and 28% (n = 5; 3 SD); for 11 OVC pts treated with E 300 mg, ORR and DCR were 18% (n = 2; 2 PR) and 36% (n = 4; 2 SD).For 25 CRC pts (all E 100 mg), ORR and DCR were 4% (n = 1; PR) and 24% (n = 6; 5 SD).Safety/efficacy evaluations are ongoing for all cohorts. Conclusions: E + N was generally well tolerated up to the maximum E 300-mg dose. P2 ORR/DCR outcomes are promising, particularly in SCCHN and MEL pts. Updated data will be presented at the meeting. Clinical trial information: NCT02327078.

Final results of a phase II multicenter trial of HF10, a replication-competent HSV-1 oncolytic virus, and ipilimumab combination treatment in patients with stage IIIB-IV unresectable or metastatic melanoma

9510

Background: HF10 is a bioselected replication-competent oncolytic virus derived from HSV-1. Herein, we report the safety and efficacy data of HF10 + ipilimumab (ipi) combination treatment in a Phase II trial in melanoma. Methods: Key entry criteria: age ≥ 18 yrs, ECOG ≤ 2, Stage IIIB, IIIC, or IV unresectable melanoma, ipi naïve (IV administration) and measurable non-visceral lesion(s) suitable for injection. HF10 injected into single or multiple tumors (1 x 107 TCID50/mL/dose, up to 5mL depending on tumor size and number); 4 injections q1wk; then up to 15 injections q3wk. Four ipi IV infusions (3 mg/kg; concurrent with HF10) were administered q3wk. AEs assessed per CTCAE 4.0. Tumor responses were assessed per mWHO and irRC at 12, 18, 24, 36 and 48 wks for patients (pts) continuing on HF10 monotherapy. Primary endpoint was Best Overall Response Rate (BORR) at 24 wks. Dose limiting toxicity (DLT) defined as ≥ G3 non-hematologic/hematologic toxicity, ≥ G2 neurologic toxicity, or allergic event occurring within 1st 3wks of therapy. Results: Of 46 pts enrolled and treated: 59% men, median age 67 yrs (range 28 to 91); disease stage 20% IIIB, 43% IIIC and 37% IV; 57% were treatment naïve and 43% with ≥ 1 prior cancer therapy for unresectable/metastatic melanoma. Most HF10-related AEs were ≤G2, similar to HF10 monotherapy. No DLTs were reported. 37% had ≥G3 AEs, the majority due to ipi. HF10-related ≥G3 AEs (n=3) were embolism, lymphedema, diarrhea, hypoglycemia, and groin pain. Of the 44 efficacy evaluable pts per irRC, BORR at 24 weeks was 41% (16% irCR and 25% irPR); disease stability rate was 68% (16% irCR, 25% irPR and 27% irSD). As of Feb 06, 2017, median PFS was 19 months and median overall survival was 21.8 months. Conclusions: The combination HF10 and ipilimumab treatment demonstrated a favorable benefit/risk profile and encouraging antitumor activity in pts with stage IIIB, IIIC, or IV unresectable or metastatic melanoma. Clinical trial information: NCT02272855.

Phase 1 trial of CA-170, a novel oral small molecule dual inhibitor of immune checkpoints PD-1 and VISTA, in patients (pts) with advanced solid tumor or lymphomas

TPS3099

Background: Programmed-death 1 (PD-1) and V-domain Ig suppressor of T-cell activation (VISTA) are independent immune checkpoints that negatively regulate T-cell function and are implicated in various malignancies. Preclinical studies have demonstrated that dual blockade of these pathways is synergistic. CA-170 is a first-in-class oral small molecule that directly targets both PD-1/PD-L1 and VISTA pathways and has shown anti-tumor activity in multiple preclinical models. Methods: The dose escalation phase has a target enrollment of 50 pts with advanced solid tumors or lymphomas onto escalating doses; the first four single-pt cohorts are accelerated titration but then switch to 3+3 design. The dose expansion phase has a target enrollment of 250 pts with select tumor types known to be responsive to anti-PD-1/L1 inhibitors and/or known to express PD-L1 or VISTA. Key eligibility criteria include: age ≥ 18 years, ECOG ≤1, adequate organ function, and ineligible for/did not respond to standard therapy including anti-PD-1/L1 inhibitors, where available. Primary objectives of this first-in-human study: safety, maximum tolerated dose, and recommended phase 2 dose. Secondary objectives: pharmacokinetics (PK) and anti-tumor activity. Exploratory endpoints: biomarkers and pharmacodynamic (PD) effects, which include changes in immune cell and peripheral cytokine populations in tumor (IHC/mRNA) and blood (flow cytometry/mRNA). Oral CA-170 is administered once daily in 21-day cycles. Response will be evaluated every other cycle per RECIST (v1.1) and Immune-related Response Criteria or by Cheson criteria (2007). Patients who discontinue treatment for reasons other than progressive disease will be followed for progression-free survival. Serial plasma, blood, and tumor samples will be collected for PK and PD evaluation. Clinical trial identifier: Clinical trial information: NCT02812875.

Five-year overall survival (OS) update from a phase II, open-label trial of dabrafenib (D) and trametinib (T) in patients (pts) with BRAF V600–mutant unresectable or metastatic melanoma (MM)

9505

Background: D (BRAF inhibitor) + T (MEK inhibitor) combination therapy is associated with rapid clinical responses and has improved clinical outcomes in pts with BRAFV600–mutant MM, but long-term (˃ 3 y) clinical efficacy and safety data are limited. The longest follow-up to date of a randomized trial evaluating D+T at the approved dose (150 mg BID/2 mg QD [150/2]) was of the phase II study BRF113220 (part C; median, 45.6 mo) in which durable outcomes were achieved in some pts with BRAFV600–mutant MM (3-y OS, 38%). Here, we report updated 5-y landmark analyses to further characterize the impact of D+T in MM. Methods: Pts with BRAFV600–mutant mm enrolled in BRF113220 part C (NCT01072175) were randomized 1:1:1 to receive monotherapy D (150 mg BID), D+T (150 mg BID/1 mg QD), or D+T (150/2). Pts who progressed on D alone could cross over to the D+T 150/2 arm. Pt disposition, pt demographics, and 4- and 5-y efficacy and safety were analyzed for both the D-alone and D+T (approved 150/2 dose) arms. Results: This updated analysis represents an additional ≈ 2 y of follow-up (D and D+T arms; n = 54 each). As of 13 Oct 2016, 45 pts (83%) on D alone had crossed over to D+T. 20 pts were ongoing (D, n = 7 [13%]; D+T, n = 13 [24%]); 80% of D pts and 70% of D+T pts had died. D+T OS remained superior to D alone. The 4- and 5-y OS rates with D+T were 30% and 28%, respectively, demonstrating a stabilization of the OS curve. The PFS curve for D+T also remained stable (4- and 5-y: both 13%). Consistent with earlier results, the best OS for pts who received D+T was seen in pts with normal LDH (5-y, 45%) and normal LDH with disease in < 3 organ sites (5-y, 51%). At the 5-y landmark, 1 additional pt who received D+T improved from a partial to a complete response. Additional follow-up revealed no new safety signals with D+T. Detailed analyses of D crossover pts, responders, and post-progression therapy will be presented. Conclusions: This longest follow-up to date of BRAF + MEK inhibitor combination therapy in pts with BRAFV600–mutant mm revealed stable OS and PFS lasting ≥ 5 y with consistent tolerability. These results demonstrate that some pts with mm can achieve durable benefit with D+T therapy. Clinical trial information: NCT01072175.

Patient attitudes toward oncofertility care in male cancer patients receiving targeted and immune therapies

e21593

Background: Tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICI) have resulted in durable response for many cancer patients. The impact of these agents on future fertility are not well described, and patients are often committed to long-term treatment without adequate oncofertility counseling. We sought to better characterize patient attitudes toward oncofertility and challenges faced by male cancer patients undergoing treatment with TKI or ICI. Methods: Men receiving TKI/ICI at the UCSF Helen Diller Family Comprehensive Cancer Center were retrospectively identified. Eligible men had received at least one dose of TKI/ICI. Detailed questionnaires addressing cancer history, possible effects of treatment on fertility, and obstacles to fertility preservation were completed. Results: Between January 2013 to September 2016, 51 men with a mean age of 46 years (SD 12, range 21-72), 65% white, completed questionnaires. Most (61%) were CML patients, with 12% RCC, 10% GIST, 6% melanoma, and NET, oligodendroglioma, and HCC comprising remaining histologies. 96% were treated with TKI, and 4% with ICI. At the time of diagnosis, 35% of patients indicated a desire to father future children, and 53% believed that cancer treatment might affect their fertility. Despite this, 45% were not asked whether having children was important to them, and 47% did not receive information from any provider on their oncology care team about the possible risks of TKI/ICI to future fertility. The majority of patients felt there was inadequate discussion of how treatment might affect testosterone levels (73%) and their ability to father a child (53%), yet only 14% recalled adequate referrals to a fertility specialist. Conclusions: These data demonstrate that male cancer patients perceive treatment-related infertility risks as important, yet have few opportunities to discuss these concerns with providers. Care plans to address oncofertility needs, especially as TKI/ICI are increasingly used in multiple cancer types, are needed as part of the diagnosis, treatment, and follow up of these patients. Larger retrospective and prospective studies are ongoing to further characterize this patient cohort.

Phase 1b/2 trial of ribociclib+binimetinib in metastatic NRAS-mutant melanoma: Safety, efficacy, and recommended phase 2 dose (RP2D)

9519

Background: Simultaneous inhibition of MEK and CDK4/6 may suppress MAPK pathway activation and cell-cycle checkpoint dysregulation in NRAS-mutant melanoma, resulting in enhanced antitumor activity. Phase 1b data are reported. Methods: The phase 1b primary objective was to determine maximum tolerated dose (MTD)/RP2D. A 28-d cycle of oral ribociclib (RIBO) once daily (QD) for 21 d + oral binimetinib (BINI) twice daily (BID) for 28 d, and a 21-d cycle of RIBO QD + BINI BID, both for 14 d per cycle, were evaluated. Secondary objectives were to evaluate efficacy, safety and pharmacodynamics. Results: Based on dose escalation (van Herpen, ESMO 2015), MTD was 600mg RIBO/45mg BINI for the 21-d and 200/45 for the 28-d regimens. Due to promising activity, the 28-d cycle was selected as RP2D(unconfirmed partial response [PR] with limited follow-up occurred in 35% of pts). This finding was supported by comparable and manageable safety and the Bayesian logistic regression model.As of Jan 2017, the RP2D was received by 16 pts in phase 1b (ECOG PS 0/1/2, 63%/31%/6%; elevated lactate dehydrogenase, 44%; stage IVM1c disease, 50%; prior ipilimumab [ipi], 44%; prior anti–programmed death [PD]-1/PD-L1, 31%). Median (range) exposure was 4 (0–13) mo. Common adverse events (AEs) were increased blood creatine phosphokinase, elevated AST, peripheral edema, acneiform dermatitis, diarrhea and fatigue. Common grade 3/4 AEs were elevated AST and ALT (19%/6%), nausea (19%/0%), rash (19%/0%), vomiting (6%/6%) and neutropenia (12%/0%). Confirmed PR (cPR) occurred in 4 pts (25%; time to response, 48–168 d), stable disease in 7 pts (44%), disease progression in 3 pts (19%); 2 pts (12%) were not evaluable. Among cPR pts, 3 had prior ipi and/or anti–PD-1/PD-L1. Median progression-free survival (mPFS) was 6.7 (95% CI, 3.5–9.2) mo. Sequence analysis of synchronous non- RAS genetic alterations will be presented. Conclusions: Combined RIBO/BINI at the selected RP2D had a manageable safety profile and favorable efficacy (based on mPFS) for NRAS-mutant melanoma in phase 1b. Based on these promising data, the phase 2 expansion is underway to assess antitumor activity at the RP2D. Clinical trial information: NCT01781572.

Relationship between liver metastases and PD-1 blockade in melanoma

3072

Background: WhilePD-1 blockade is effective in melanoma, durable responses remain elusive. We have previously reported that liver metastasis is associated with reduced response rates and that the fraction of CTLA4 hi/PD-1 hi CD8+ cells (“activated-exhausted” or T-ex cells) within the TIL is predictive of response to PD-1 blockade. Here, we explore the biology behind liver metastasis in human melanoma and in animal models. Methods: Patients with metastatic melanoma with or without liver metastasis were biopsied pre- PD-1 treatment and immune infiltrates were analyzed by FACS. The CD8 fraction was gated on CTLA4 and PD-1. C57BL/6 mice were implanted with a “primary” subcutaneous tumor and a “metastatic” tumor in the liver or the lungs (control), and given systemic PD-1 blockade therapy. Results: Patients with melanoma and liver metastasis (n = 25) had 15.2% T-ex cells while those without liver metastasis (n = 76) had 26.5 % T-ex cells, p = 0.0092. A T-ex fraction < 20% was significantly associated with lack of PD-1 response, p < 0.005. In C57BL/6 mice implanted with a B16 tumor (subQ & liver) treated with PD-1 antibody, 0/35 mice achieved subQ tumor rejection while in the SubQ only mice 9/30 mice (30%) rejected their tumors. The mean tumor size of mice with Sub Q+liver metastasis was 139.2 mm2 vs subQ only mice 23.4 mm2 at d 14, p = 0.002. Mice with liver metastasis showed a T-ex fraction 31.9% vs 67.3%without liver met, p = 0.0003. In contrast, in mice made lung metastatic, the subQ tumor rejection rate was 7/20 (35%), with T-ex infiltrate at 57.9%. The implantation of liver metastases from an unrelated MC38 tumor does not protect the subQ tumor from immune rejection. Conclusions: The presence of liver metastases is associated with reduced response to PD-1 blockade and reduced T-ex infiltrate in patients with stage IV melanoma. Mechanistic studies using a mouse model of syngeneic organ site specific metastasis confirms that the liver metastasis results in reduced antigen specific T cell at distant sites, resulting in reduced response. Site of metastasis may determine immune responsiveness in both mouse models and in humans with melanoma.

Management of Treatment-Related Adverse Events with Agents Targeting the MAPK Pathway in Patients with Metastatic Melanoma

Tremendous progress has been made in the clinical landscape of advanced-stage BRAF V600-mutant melanoma treatment over the past 5 years. Targeted therapies that inhibit specific steps of the mitogen-activated protein kinase pathway have been shown to provide significant overall treatment benefit in patients with this difficult-to-treat disease. Combination therapy with BRAF and MEK inhibitors (dabrafenib plus trametinib or vemurafenib plus cobimetinib, respectively) has become standard of care. These agents are administered until disease progression or unacceptable toxicity occurs; thus, some patients may remain on maintenance therapy for an extended period of time, while toxicities may result in early discontinuation in other patients. Because the goal of treatment is to prolong survival with minimal impairment of quality of life, drug-related adverse events (AEs) require prompt management to ensure that patients derive the best possible benefit from therapy. Proper management depends on an understanding of which AEs are most likely BRAF or MEK inhibitor associated, thus providing a rationale for dose modification of the appropriate drug. Additionally, the unique safety profile of the chosen regimen may influence patient selection and monitoring. This review discusses the toxicity profiles of these agents, with a focus on the most commonly reported and serious AEs. Here, we offer practical guidance derived from our clinical experience for the optimal management of key drug-related AEs.

IMPLICATIONS FOR PRACTICE

Targeted therapy with BRAF plus MEK inhibitors has become the standard of care for patients with advanced-stage BRAF V600-mutant metastatic melanoma. To provide optimal therapeutic benefit to patients, clinicians need a keen understanding of the toxicity profiles of these drugs. Prompt identification and an understanding of which adverse events are most likely BRAF or MEK inhibitor associated provide a rationale for appropriate therapy adjustments. Practical recommendations derived from clinical experience are provided for management of key drug-related toxicities.

Liver Metastasis and Treatment Outcome with Anti-PD-1 Monoclonal Antibody in Patients with Melanoma and NSCLC

We explored the association between liver metastases, tumor CD8⁺ T-cell count, and response in patients with melanoma or lung cancer treated with the anti-PD-1 antibody, pembrolizumab. The melanoma discovery cohort was drawn from the phase I Keynote 001 trial, whereas the melanoma validation cohort was drawn from Keynote 002, 006, and EAP trials and the non-small cell lung cancer (NSCLC) cohort from Keynote 001. Liver metastasis was associated with reduced response and shortened progression-free survival [PFS; objective response rate (ORR), 30.6%; median PFS, 5.1 months] compared with patients without liver metastasis (ORR, 56.3%; median PFS, 20.1 months) P ≤ 0.0001, and confirmed in the validation cohort (P = 0.0006). The presence of liver metastasis significantly increased the likelihood of progression (OR, 1.852; P < 0.0001). In a subset of biopsied patients (n = 62), liver metastasis was associated with reduced CD8⁺ T-cell density at the invasive tumor margin (liver metastasis⁺ group, n = 547 ± 164.8; liver metastasis^- group, n = 1,441 ± 250.7; P < 0.016). A reduced response rate and shortened PFS was also observed in NSCLC patients with liver metastasis [median PFS, 1.8 months; 95% confidence interval (CI), 1.4-2.0], compared with those without liver metastasis (n = 119, median PFS, 4.0 months; 95% CI, 2.1-5.1), P = 0.0094. Thus, liver metastatic patients with melanoma or NSCLC that had been treated with pembrolizumab were associated with reduced responses and PFS, and liver metastases were associated with reduced marginal CD8⁺ T-cell infiltration, providing a potential mechanism for this outcome. Cancer Immunol Res; 5(5); 417-24. ©2017 AACR.

Immune monitoring outcomes of patients with stage III/IV melanoma treated with a combination of pembrolizumab and intratumoral plasmid interleukin 12 (pIL-12)

78

Background: Recent publications support the emergence of predictive biomarkers for pembrolizomab in melanoma based on the expression of PD-L1 in the tumor microenvironment (Daud 2016a) or the frequency of PD-1hiCTLA-4hi on CD8+ TIL (Daud 2016b) whereby immunologically inactive tumors show poor response to immune checkpoint inhibition alone. Since intratumoral pIL-12 with electroporation (IT-pIL12-EP) increases TIL in both treated and untreated lesions, we hypothesize that non-response can be rescued with the combination of IT-pIL12-EP and anti-PD-1. Phase II clinical and immunological data are shown. Methods: Melanoma stage III/IV patients were enrolled with CD8+ TIL < 25% PD-1hiCTLA-4+measured by flow cytometry (NCT02493361). PD-L1 IHC (22C3 Ab) was also evaluated. Patients were treated with pembrolizumab (200mg every 3 weeks) and IT-pIL12-EP. Patients were evaluated for ORR every 12 weeks (RECISTv1.1). Pre- and post-treatment blood and tumor specimens were collected, and analyzed for immune phenotyping, gene expression, T cell receptor diversity, and changes in the tumor microenvironment by IHC. Results: TIL assessment for evaluable enrolled patients were < 22% PD-1hiCTLA-4+, a value associated with anti-PD-1 non-response (Daud 2016b). Remarkably, although predicted to be an unresponsive population, the ORR was 40% (4CR/ 2PR) by RECISTv1.1. In patients with CR/PR, analysis of the tumor microenvironment revealed many significant immunological changes not seen in non-responders, including number and ratios of CD8+:PD-L1+by IHC, increased expression of NK, CD8 and ‘adaptive resistance’ markers by NanoString, as well as increased clonality and T cells by TCR sequencing. Conclusions: The excellent safety profile and striking 40% clinical response rate is encouraging as treated patients were predicted to be non-responsive to pembrolizumab. The correlative data shows an immune-directed mechanism that is differentiated between responders and non-responders suggesting the combination can effectively alter the tumor microenviroment to benefit patients otherwise unlikely to respond to anti-PD-1 monotherapy. Clinical trial information: NCT02493361.

Phase II randomised discontinuation trial of the MET/VEGF receptor inhibitor cabozantinib in metastatic melanoma

BACKGROUND

A phase II randomised discontinuation trial assessed cabozantinib (XL184), an orally bioavailable inhibitor of tyrosine kinases including VEGF receptors, MET, and AXL, in a cohort of patients with metastatic melanoma.

METHODS

Patients received cabozantinib 100 mg daily during a 12-week lead-in. Patients with stable disease (SD) per Response Evaluation Criteria in Solid Tumours (RECIST) at week 12 were randomised to cabozantinib or placebo. Primary endpoints were objective response rate (ORR) at week 12 and postrandomisation progression-free survival (PFS).

RESULTS

Seventy-seven patients were enroled (62% cutaneous, 30% uveal, and 8% mucosal). At week 12, the ORR was 5%; 39% of patients had SD. During the lead-in phase, reduction in target lesions from baseline was seen in 55% of evaluable patients overall and in 59% of evaluable patients with uveal melanoma. Median PFS after randomisation was 4.1 months with cabozantinib and 2.8 months with placebo (hazard ratio of 0.59; P=0.284). Median PFS from study day 1 was 3.8 months, 6-month PFS was 33%, and median overall survival was 9.4 months. The most common grade 3/4 adverse events were fatigue (14%), hypertension (10%), and abdominal pain (8%). One treatment-related death was reported from peritonitis due to diverticular perforation.

CONCLUSIONS

Cabozantinib has clinical activity in patients with metastatic melanoma, including uveal melanoma. Further clinical investigation is warranted.

Indirect treatment comparison of dabrafenib plus trametinib versus vemurafenib plus cobimetinib in previously untreated metastatic melanoma patients

Background

Metastatic melanoma is an aggressive form of skin cancer with a high mortality rate and the fastest growing global incidence rate of all malignancies. The introduction of BRAF/MEK inhibitor combinations has yielded significant increases in PFS and OS for melanoma. However, at present, no direct comparisons between different BRAF/MEK combinations have been conducted. In light of this, an indirect treatment comparison was performed between two BRAF/MEK inhibitor combination therapies for metastatic melanoma, dabrafenib plus trametinib and vemurafenib plus cobimetinib, in order to understand the relative efficacy and toxicity profiles of these therapies.

Methods

A systematic literature search identified two randomized trials as suitable for indirect comparison: the coBRIM trial of vemurafenib plus cobimetinib versus vemurafenib and the COMBI-v trial of dabrafenib plus trametinib versus vemurafenib. The comparison followed the method of Bucher et al. and analyzed both efficacy (overall survival [OS], progression-free survival [PFS], and overall response rate [ORR]) and safety outcomes (adverse events [AEs]).

Results

The indirect comparison revealed similar efficacy outcomes between both therapies, with no statistically significant difference between therapies for OS (hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.68 − 1.30), PFS (HR 1.05, 95% CI 0.79 − 1.40), or ORR (risk ratio [RR] 0.90, 95% CI 0.74 − 1.10). Dabrafenib plus trametinib differed significantly from vemurafenib plus cobimetinib with regard to the incidence of treatment-related AE (RR 0.92, 95% CI 0.87 − 0.97), any AE grade ≥3 (RR 0.71, 95% CI 0.60 − 0.85) or dose interruption/modification (RR 0.77, 95% CI 0.60 − 0.99). Several categories of AEs occurred significantly more frequently with vemurafenib plus cobimetinib, while some occurred significantly more frequently with dabrafenib plus trametinib. For severe AEs (grade 3 or above), four occurred significantly more frequently with vemurafenib plus cobimetinib and no severe AE occurred significantly more frequently with dabrafenib plus trametinib.

Conclusions

This indirect treatment comparison suggested that dabrafenib plus trametinib had comparable efficacy to vemurafenib plus cobimetinib but was associated with reduced adverse events.