Survival and clinical outcomes of patients with melanoma brain metastasis in the era of checkpoint inhibitors and targeted therapies.

BACKGROUND: Melanoma brain metastasis is associated with an extremely poor prognosis, with a median overall survival of 4-5 months. Since 2011, the overall survival of patients with stage IV melanoma has been significantly improved with the advent of new targeted therapies and checkpoint inhibitors. We analyze the survival outcomes of patients diagnosed with brain metastasis after the introduction of these novel drugs. METHODS: We performed a retrospective analysis of our melanoma center database and identified 79 patients with brain metastasis between 2011 and 2015. RESULTS: The median time from primary melanoma diagnosis to brain metastasis was 3.2 years. The median overall survival duration from the time of initial brain metastasis was 12.8 months. Following a diagnosis of brain metastasis, 39 (49.4%), 28 (35.4%), and 24 (30.4%) patients were treated with anti-CTLA-4 antibody, anti-PD-1 antibody, or BRAF inhibitors (with or without a MEK inhibitor), with a median overall survival of 19.2 months, 37.9 months and 12.7 months, respectively. Factors associated with significantly reduced overall survival included male sex, cerebellar metastasis, higher number of brain lesions, and treatment with whole-brain radiation therapy. Factors associated with significantly longer overall survival included treatment with craniotomy, stereotactic radiosurgery, or with anti-PD-1 antibody after initial diagnosis of brain metastasis. CONCLUSIONS: These results show a significant improvement in the overall survival of patients with melanoma brain metastasis in the era of novel therapies. In addition, they suggest the activity of anti-PD-1 therapy specifically in the setting of brain metastasis.

Combined nivolumab and ipilimumab versus ipilimumab alone in patients with advanced melanoma: 2-year overall survival outcomes in a multicentre, randomised, controlled, phase 2 trial.

BACKGROUND: Results from phase 2 and 3 trials in patients with advanced melanoma have shown significant improvements in the proportion of patients achieving an objective response and prolonged progression-free survival with the combination of nivolumab (an anti-PD-1 antibody) plus ipilimumab (an anti-CTLA-4 antibody) compared with ipilimumab alone. We report 2-year overall survival data from a randomised controlled trial assessing this treatment in previously untreated advanced melanoma. METHODS: In this multicentre, double-blind, randomised, controlled, phase 2 trial (CheckMate 069) we recruited patients from 19 specialist cancer centres in two countries (France and the USA). Eligible patients were aged 18 years or older with previously untreated, unresectable stage III or IV melanoma and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned 2:1 to receive an intravenous infusion of nivolumab 1 mg/kg plus ipilimumab 3 mg/kg or ipilimumab 3 mg/kg plus placebo, every 3 weeks for four doses. Subsequently, patients assigned to nivolumab plus ipilimumab received nivolumab 3 mg/kg every 2 weeks until disease progression or unacceptable toxicity, whereas patients allocated to ipilimumab alone received placebo every 2 weeks during this phase. Randomisation was done via an interactive voice response system with a permuted block schedule (block size of six) and stratification by BRAF mutation status. The study funder, patients, investigators, and study site staff were masked to treatment assignment. The primary endpoint, which has been reported previously, was the proportion of patients with BRAFV600 wild-type melanoma achieving an investigator-assessed objective response. Overall survival was an exploratory endpoint and is reported in this Article. Efficacy analyses were done on the intention-to-treat population, whereas safety was assessed in all treated patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT01927419, and is ongoing but no longer enrolling patients. FINDINGS: Between Sept 16, 2013, and Feb 6, 2014, we screened 179 patients and enrolled 142, randomly assigning 95 patients to nivolumab plus ipilimumab and 47 to ipilimumab alone. In each treatment group, one patient no longer met the study criteria following randomisation and thus did not receive study drug. At a median follow-up of 24·5 months (IQR 9·1-25·7), 2-year overall survival was 63·8% (95% CI 53·3-72·6) for those assigned to nivolumab plus ipilimumab and 53·6% (95% CI 38·1-66·8) for those assigned to ipilimumab alone; median overall survival had not been reached in either group (hazard ratio 0·74, 95% CI 0·43-1·26; p=0·26). Treatment-related grade 3-4 adverse events were reported in 51 (54%) of 94 patients who received nivolumab plus ipilimumab compared with nine (20%) of 46 patients who received ipilimumab alone. The most common treatment-related grade 3-4 adverse events were colitis (12 [13%] of 94 patients) and increased alanine aminotransferase (ten [11%]) in the combination group and diarrhoea (five [11%] of 46 patients) and hypophysitis (two [4%]) in the ipilimumab alone group. Serious grade 3-4 treatment-related adverse events were reported in 34 (36%) of 94 patients who received nivolumab plus ipilimumab (including colitis in ten [11%] of 94 patients, and diarrhoea in five [5%]) compared with four (9%) of 46 patients who received ipilimumab alone (including diarrhoea in two [4%] of 46 patients, colitis in one [2%], and hypophysitis in one [2%]). No new types of treatment-related adverse events or treatment-related deaths occurred in this updated analysis. INTERPRETATION: Although follow-up of the patients in this study is ongoing, the results of this analysis suggest that the combination of first-line nivolumab plus ipilimumab might lead to improved outcomes compared with first-line ipilimumab alone in patients with advanced melanoma. The results suggest encouraging survival outcomes with immunotherapy in this population of patients. FUNDING: Bristol-Myers Squibb.

Phase 2 Study of Intralesional PV-10 in Refractory Metastatic Melanoma.

PURPOSE: This international, multicenter, single-arm trial assessed efficacy and safety of intralesional rose bengal (PV-10) in 80 patients with refractory cutaneous or subcutaneous metastatic melanoma. METHODS: Sixty-two stage III and 18 stage IV melanoma patients with disease refractory to a median of six prior interventions received intralesional PV-10 into up to 20 cutaneous and subcutaneous lesions up to four times over a 16-week period and were followed for 52 weeks. Objectives were to determine best overall response rate in injected target lesions and uninjected bystander lesions, assess durability of response, and characterize adverse events. RESULTS: For target lesions, the best overall response rate was 51 %, and the complete response rate was 26 %. Median time to response was 1.9 months, and median duration of response was 4.0 months, with 8 % of patients having no evidence of disease after 52 weeks. Response was dependent on untreated disease burden, with complete response achieved in 50 % of patients receiving PV-10 to all of their disease. Response of target lesions correlated with bystander lesion regression and the occurrence of locoregional blistering. Adverse events were predominantly mild to moderate and locoregional to the treatment site, with no treatment-associated grade 4 or 5 adverse events. CONCLUSIONS: Intralesional PV-10 yielded durable local control with high rates of complete response. Toxicity was confined predominantly to the injection site. Cutaneous bystander tumor regression is consistent with an immunologic response secondary to ablation. This intralesional approach for local disease control could be complementary to current and investigational treatments for melanoma.

Extended long-term follow-up of metastatic melanoma patients treated with immunotherapy: late relapses and second primary melanomas.

Background: Immunotherapy has revolutionized the treatment of patients with advanced melanoma as well as other cancers. Most studies, whether of interleukin-2 or checkpoint inhibitor therapies, have limited follow-up after 5 years, making the incidence of late relapses uncertain. In addition, the incidence of second primary melanomas in patients with stage IV melanoma treated with immunotherapy has rarely been reported. Methods: We performed a single-institution retrospective study of stage IV melanoma patients treated with interleukin-2 or checkpoint inhibitors over the period from 1992 to 2013. We found 59 patients alive and in remission 5 years after the beginning of immunotherapy and reviewed their subsequent clinical course. Results: This 59-patient cohort had a median follow-up of 13.1 years, with 36 patients followed up for at least 10 years. Four patients (6.8%) had relapses of their metastatic melanoma at 5, 8, 15, and 17 years after starting the successful immunotherapy. Three of the four are still alive. Only one patient in 690 patient-years of observation had a second primary invasive melanoma. Conclusion: Although late relapses after immunotherapy for melanoma do occur, we can conclude that the prognosis of stage IV melanoma patients in continuous remission 5 years after starting immunotherapy is excellent, with a progression-free survival of approximately 85% and a melanoma-specific survival of approximately 95% at 20 years in our series. Our incidence of second primary melanomas is lower than usually reported. These results have important implications regarding the follow-up of stage IV melanoma patients successfully treated with immunotherapy.

Yttrium-90 radioembolization of renal cell carcinoma metastatic to the liver.

PURPOSE: To investigate the safety and efficacy of yttrium-90 ((90)Y) hepatic radioembolization treatment of patients with liver-dominant metastatic renal cell carcinoma (RCC) refractory to immunotherapy and targeted therapies. MATERIALS AND METHODS: Between March 2006 and December 2010, six patients with metastatic RCC underwent eight radioembolization treatments with (90)Y-labeled resin microspheres for unresectable liver-dominant metastases. All six patients had previous hepatic tumor progression despite targeted therapies or immunotherapies. All had bilobar disease and required whole-liver treatment. Clinical and biochemical toxicities were recorded, and tumor response was assessed every 2-3 months after treatment by cross-sectional imaging. RESULTS: The median dose delivered was 1.89 Gbq (range 0.41-2.03 Gbq). Grade 1 and 2 toxicities were noted in all patients, primarily fatigue. Follow-up imaging was available for five patients. In follow-up periods from 2-64 months (mean 25 months), three patients showed complete responses, and 1 patient showed a partial response by standard imaging criteria, and these patients are alive at 64 months, 55 months, 17 months, and 7 months after treatment. Two patients with rapid progression of disease died within 2 months of treatment, although hepatic malignancy or failure was not the cause of death in either patient. CONCLUSIONS: (90)Y radioembolization is a promising option for liver-dominant metastatic RCC with potential for providing long-term survival in patients refractory to or intolerant of targeted therapies.

A Pilot Study of Hepatic Irradiation with Yttrium-90 Microspheres Followed by Immunotherapy with Ipilimumab and Nivolumab for Metastatic Uveal Melanoma.

Background: Liver metastases from uveal melanoma carry a very poor prognosis. Hepatic artery infusions with Yttrium-90 (90Y) resin microspheres have some activity in this disease, and radiation and immunotherapy may be synergistic. The primary objective of this study was to determine the safety and tolerability of sequential 90Y resin microspheres and immunotherapy with ipilimumab and nivolumab in metastatic uveal melanoma. Materials and Methods: Twenty-six patients with uveal melanoma with hepatic metastases were entered into a pilot study. Treatment consisted of two infusions of 90Y resin microspheres, one to each lobe of the liver, followed in 2-4 weeks by immunotherapy with ipilimumab and nivolumab every 3 weeks for four doses, then maintenance immunotherapy with nivolumab alone. Results: Initial dosing of both 90Y and immunotherapy resulted in excessive toxicity. With decreasing the dosage of 90Y to limit the normal liver dose to 35Gy and lowering the ipilimumab dose to 1 mg/kg, the toxicity was tolerable, with no apparent change in efficacy. There was one complete and four confirmed partial responses, for an objective response rate of 20% and a disease control rate of 68%. The median progression-free survival was 5.5 months (95% confidence interval [CI]: 1.3-9.7 months), with a median overall survival of 15 months (95% CI: 9.7-20.1 months). Conclusions: With dose reductions, sequential therapy with 90Y and immunotherapy with ipilimumab and nivolumab is safe and tolerable, and has activity in metastatic uveal melanoma. These results justify a controlled trial to demonstrate whether 90Y resin microspheres add to the utility of combination immunotherapy in this disease. Clinical Trial Registration number: NCT02913417.

Immune adverse events (irAEs) with adjuvant ipilimumab in melanoma, use of immunosuppressants and association with outcome: ECOG-ACRIN E1609 study analysis.

BACKGROUND: The impact of immune-related adverse events (irAEs) occurring from adjuvant use of immunotherapy and of their management on relapse-free survival (RFS) and overall survival (OS) outcomes is currently not well understood. PATIENTS AND METHODS: E1609 enrolled 1673 patients with resected high-risk melanoma and evaluated adjuvant ipilimumab 3 mg/kg (ipi3) and 10 mg/kg (ipi10) versus interferon-α. We investigated the association of irAEs and of use of immunosuppressants with RFS and OS for patients treated with ipilimumab (n=1034). RESULTS: Occurrence of grades 1-2 irAEs was associated with RFS (5 years: 52% (95% CI 47% to 56%) vs 41% (95% CI 31% to 50%) with no AE; p=0.006) and a trend toward improved OS (5 years: 75% (95% CI 71% to 79%) compared with 67% (95% CI 56% to 75%) with no AE; p=0.064). Among specific irAEs, grades 1-2 rash was most significantly associated with RFS (p=0.002) and OS (p=0.003). In multivariate models adjusting for prognostic factors, the most significant associations were seen for grades 1-2 rash with RFS (p<0.001, HR=0.70) and OS (p=0.01, HR=0.71) and for grades 1-2 endocrine+rash with RFS (p<0.001, HR=0.66) and OS (p=0.008, HR=0.7). Overall, grades 1-2 irAEs had the best prognosis in terms of RFS and OS and those with grades 3-4 had less RFS benefits and no OS advantage over no irAE. Patients experiencing grades 3-4 irAE had significantly higher exposure to corticosteroids and immunosuppressants than those with grades 1-2 (92% vs 60%; p<0.001), but no significant associations were found between corticosteroid and immunosuppressant use and RFS or OS. In investigating the impact of non-corticosteroid immunosuppressants, although there were trends toward better RFS and OS favoring cases who were not exposed, no significant associations were found. CONCLUSIONS: Rash and endocrine irAEs were independent prognostic factors of RFS and OS in patients treated with adjuvant ipilimumab. Patients experiencing lower grade irAEs derived the most benefit, but we found no significant evidence supporting a negative impact of high dose corticosteroids and immunosuppressants more commonly used to manage grades 3-4 irAEs.

Prevalence of Homologous Recombination Pathway Gene Mutations in Melanoma: Rationale for a New Targeted Therapeutic Approach.

Homologous recombination DNA damage repair (HR-DDR) deficient patients with various solid tumors have been treated with PARP inhibitors. However, the clinical characteristics of patients with melanoma who have HR-DDR gene mutations and the consequences of PARP inhibition are poorly understood. We compared the commercially available next-generation sequencing data from 84 patients with melanomas from our institution with a dataset of 1,986 patients as well as 1,088 patients profiled in cBioportal. In total, 21.4% of patients had ≥1 functional HR-DDR mutation, most commonly involving BRCA1, ARID1A, ATM, ATR, and FANCA. Concurrent NF1, BRAF, and NRAS mutations were found in 39%, 39%, and 22% of cases, respectively. HR-DDR gene mutation was associated with high tumor mutational burden and clinical response to checkpoint blockade. A higher prevalence of HR-DDR mutations was observed in the datasets from Foundation Medicine (Cambridge, CA) and those from the Cancer Genome Atlas. Treatment of HR-DDR‒mutated patient-derived xenograft models of melanoma with PARP inhibitor produced significant antitumor activity in vivo and was associated with increased apoptotic activity. RNA sequencing analysis of PARP inhibitor-treated tumors indicated alterations in the pathways involving extracellular matrix remodeling, cell adhesion, and cell-cycle progression. Melanomas with HR-DDR mutations represent a unique subset, which is more likely to benefit from checkpoint blockade and may be targeted with PARP inhibitor.

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.

Prognostic factors in metastatic melanoma patients treated with biochemotherapy and maintenance immunotherapy.

BACKGROUND: With no U.S. Food and Drug Administration-approved standard therapy other than high-dose interleukin-2 and dacarbazine for metastatic melanoma, biochemotherapy has shown promise, with long-term survival in selected patients. We felt that the study of prognostic factors would determine which patients might benefit from this intensive therapy. METHODS: One hundred thirty-five consecutive patients with metastatic melanoma treated with decrescendo biochemotherapy followed by maintenance immunotherapy over 5 years were retrospectively studied to determine the most important prognostic factors for both overall survival and progression-free survival. RESULTS: The median overall survival (OS) time was 16.6 months, with 1-year and 5-year survival rates of 70% and 28%, respectively. The median progression-free survival (PFS) time was 7.6 months, with 15% of patients progression free at 5 years. PFS curves showed no relapses after 30 months, so remissions were durable. For OS, a performance status score of zero, normal lactate dehydrogenase (LDH) level, stage M1a, and nonvisceral sites of metastasis were favorable factors. The group with normal LDH levels and skin or nodes as one of their metastatic sites had a relatively good prognosis, with median survival time of 44 months and an estimated 5-year survival rate of 38%. Conversely, patients with an elevated LDH level without any skin or nodal metastases had a poor prognosis, with no long-term survivors. CONCLUSIONS: Metastatic melanoma patients treated with biochemotherapy and maintenance immunotherapy who have either a normal LDH level or skin or nodes as one of their metastatic sites may have durable remissions of their disease, and this therapy should be studied further in these groups.

Prolonged survival after intraperitoneal interleukin-2 immunotherapy for recurrent ovarian cancer.

•A case report of a 14 year remission of recurrent ovarian cancer with intraperitoneal aldesleukin (IL-2) is presented.•Intraperitoneal IL-2 was given with little toxicity.•Immunotherapy may have the potential for durable remissions in ovarian cancer.

A retrospective study of biochemotherapy for metastatic melanoma: the importance of dose intensity.

BACKGROUND: The utility of biochemotherapy for metastatic melanoma remains controversial. Dose intensity has been recognized as an important determinant of response and survival in the chemotherapy of several malignancies but has not been studied in biochemotherapy. In this retrospective study, we described the relationship between achieved dose intensity and the response rate of inpatient decrescendo biochemotherapy at our center. METHODS: A study of 38 consecutive patients with metastatic melanoma was undertaken. The planned doses were dacarbazine 800 mg/m(2) on day 1 or temozolomide 150 mg/m(2) on days 1-4, cisplatin 20 mg/m(2) on days 1-4, vinblastine 1.5 mg/m(2) on days 1-4, interferon-alpha-2b (Schering) 5 million IU (MIU)/m(2) on days 1-5, and interleukin-2 36 MIU on day 1, 18 MIU on day 2, and 9 MIU on days 3 and 4. RESULTS: Of 38 patients that received a total of 204 cycles of therapy, 8 (21%) complete responses and 14 (37%) partial responses were observed for an objective response rate of 58%. Median survival was 19.6 months. Achieved dose intensity was high with patients receiving 98.7% interleukin- 2, 87.1% interferon, 90.7% dacarbazine (DTIC), 94% temozolomide, 87.2% cisplatin, and 89.7% vinblastine. CONCLUSIONS: Six cycles of inpatient decrescendo biochemotherapy can be given with high-dose intensity and acceptable toxicity. High response rates with biochemotherapy for melanoma may correlate with dose intensity, dose density, and the number of cycles given on time.

Successful desensitization in a case of Stevens-Johnson syndrome due to vemurafenib.

The BRAF inhibitor vemurafenib can cause severe cutaneous reactions, including Stevens-Johnson syndrome, particularly when administered after ipilimumab, which usually prevents further drug administration. We report the case of a patient with Stevens-Johnson syndrome due to vemurafenib, who was retreated with vemurafenib with a program of slow desensitization with dexamethasone and diphenhydramine. Vemurafenib was tolerated at a 50% dose after a 3-week desensitization. Desensitization may be possible in patients who develop Stevens-Johnson syndrome after vemurafenib treatment.

Sunitinib therapy for melanoma patients with KIT mutations.

PURPOSE: Recent studies have shown activating KIT mutations in melanoma originating from mucosa, acral, or cumulative sun-damaged skin sites. We aimed to assess the predictive role of KIT mutation, amplification, or overexpression for response to treatment with the kinase inhibitor sunitinib. EXPERIMENTAL DESIGN: Tumor tissues from 90 patients with stage III or IV acral, mucosal, or cumulative sun-damaged skin melanoma underwent sequencing of KIT, BRAF, NRAS, and GNAQ genes, FISH analysis for KIT amplification, and immunohistochemistry of KIT protein (CD117). Patients with mutations, amplifications, or overexpression of KIT were treated with sunitinib and responses measured by Response Evaluation Criteria in Solid Tumors (RECIST). RESULTS: Eleven percent of the melanomas tested had mutations in KIT, 23% in BRAF, 14% in NRAS, and none in GNAQ. Of 12 patients treated with sunitinib, 10 were evaluable. Of the 4 evaluable patients with KIT mutations, 1 had a complete remission for 15 months and 2 had partial responses (1- and 7-month duration). In contrast, only 1 of the 6 patients with only KIT amplification or overexpression alone had a partial response. In 1 responder with rectal melanoma who later progressed, the recurring tumor had a previously undetected mutation in NRAS, which was found in addition to the persisting mutation in KIT. Interestingly, among patients with manifest stage IV disease, KIT mutations were associated with a significantly shortened survival time (P < 0.0001). CONCLUSIONS: Sunitinib may have activity in patients with melanoma and KIT mutations; more study is needed. KIT mutations may represent an adverse prognostic factor in metastatic melanoma.

Releasing the brake on the immune system: ipilimumab in melanoma and other tumors.

Advanced melanoma has proven difficult to treat for many years, and no previous agent has shown improved survival in a phase 3 trial. The deepening understanding of tumor immunobiology and the complexity of the interactions between host T cells and cancer have led to novel treatment approaches. Among these, ipilimumab is a first-in-class T-cell potentiator that works by blocking cytotoxic T-lymphocyte antigen-4, a critical negative regulator of the antitumor T-cell response. From phase 1 studies, ipilimumab has shown encouraging activity in melanoma and other cancers, with unusual response patterns and mechanism-related, predictable toxicities that are medically manageable and mostly reversible but can sometimes be life threatening unless recognized and treated early. Early indications of a survival benefit in phase 2 studies have been confirmed recently in the first randomized phase 3 trial; the primary endpoint of the trial, overall survival (OS), was met with ipilimumab significantly prolonging median OS both as a single agent (10.1 months; p = 0.003) and combined with gp100 vaccine (10.0 months; p < 0.001) compared with vaccine control (6.4 months). Even more noteworthy was the improvement in long-term survival at 24 months from 13.7% (gp100 alone) to 21.6% and 23.5% for the combination and single ipilimumab, respectively. The addition of gp100 vaccine did not appear to impact OS since data for ipilimumab alone were similar to those for the combination with vaccine. Re-induction with ipilimumab in selected patients who progressed gave further clinical benefits. Ipilimumab has also shown promising activity in melanoma patients with brain metastases, and patients with non-small cell lung cancer, renal cell cancer, and castrate-resistant prostate cancer. Ipilimumab not only has a novel mechanism of action but demonstrates unique immune-related toxicities that require particular care in their recognition and treatment.