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BackgroundPatients with melanoma that progresses on ipilimumab and, if BRAF(V600) mutant-positive, a BRAF or MEK inhibitor or both, have few treatment options. We assessed the efficacy and safety of two pembrolizumab doses versus investigator-choice chemotherapy in patients with ipilimumab-refractory melanoma.MethodsWe carried out a randomised phase 2 trial of patients aged 18 years or older from 73 hospitals, clinics, and academic medical centres in 12 countries who had confirmed progressive disease within 24 weeks after two or more ipilimumab doses and, if BRAF(V600) mutant-positive, previous treatment with a BRAF or MEK inhibitor or both. Patients had to have resolution of all ipilimumab-related adverse events to grade 0-1 and prednisone 10 mg/day or less for at least 2 weeks, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and at least one measurable lesion to be eligible. Using a centralised interactive voice response system, we randomly assigned (1:1:1) patients in a block size of six to receive intravenous pembrolizumab 2 mg/kg or 10 mg/kg every 3 weeks or investigator-choice chemotherapy (paclitaxel plus carboplatin, paclitaxel, carboplatin, dacarbazine, or oral temozolomide). Randomisation was stratified by ECOG performance status, lactate dehydrogenase concentration, and BRAF(V600) mutation status. Individual treatment assignment between pembrolizumab and chemotherapy was open label, but investigators and patients were masked to assignment of the dose of pembrolizumab. We present the primary endpoint at the prespecified second interim analysis of progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT01704287. The study is closed to enrolment but continues to follow up and treat patients.FindingsBetween Nov 30, 2012, and Nov 13, 2013, we enrolled 540 patients: 180 patients were randomly assigned to receive pembrolizumab 2 mg/kg, 181 to receive pembrolizumab 10 mg/kg, and 179 to receive chemotherapy. Based on 410 progression-free survival events, progression-free survival was improved in patients assigned to pembrolizumab 2 mg/kg (HR 0·57, 95% CI 0·45-0·73; p

Background: Ipilimumab (IPI), an anti-CTLA-4 antibody, and vemurafenib (VEM), a BRAF inhibitor, have distinct mechanisms of action and shared toxicities (e.g., skin, gastrointestinal [GI] and hepatobiliary disorders) that may preclude concomitant administration. Concurrent administration of IPI and VEM previously showed significant dose-limiting hepatotoxicity in advanced melanoma. This single-arm, open-label, phase II study evaluated a sequencing strategy with these two agents in previously untreated patients with BRAF-mutated advanced melanoma. Methods: This study was divided into two parts. During Part 1 (VEM1-IPI), patients received VEM 960 mg twice daily for 6 weeks followed by IPI 10 mg/kg every 3 weeks for 4 doses (induction), then every 12 weeks (maintenance) beginning at week 24 until disease progression or unacceptable toxicity. During Part 2 (VEM2), patients who progressed after IPI received VEM at their previously tolerated dose. The primary objective was to estimate the incidence of grade 3/4 drug-related skin adverse events (AEs) during VEM1-IPI. Results: All patients who were initially treated with VEM (n = 46) received IPI induction therapy; 8 received IPI maintenance and 19 were treated during VEM2. During VEM1-IPI, the incidence of grade 3/4 drug-related AEs associated with the skin, GI tract, and hepatobiliary system was 32.6%, 21.7%, and 4.3%, respectively. There were no drug-related deaths. At a median follow-up of 15.3 months, median overall survival was 18.5 months. Median progression-free survival was 4.5 months. Conclusions: VEM (960 mg twice daily for 6 weeks) followed by IPI 10 mg/kg has a manageable safety profile. The benefits/risks of BRAF inhibitors followed by immunotherapy should be evaluated further in light of continuing developments in treatment options for metastatic melanoma. [ABSTRACT FROM AUTHOR]

Stage IV metastatic melanoma patients historically have a poor prognosis with 5-10% 5-year survival. Ipilimumab, a monoclonal antibody against cytotoxic T-lymphocyte antigen 4 (CTLA4), is one of the first treatments to provide beneficial durable responses in advanced melanoma. However, less than 25% of those treated benefit, treatment is expensive, and side effects can be fatal. Since soluble (s) CTLA4 may mediate inhibitory effects previously ascribed to the membrane-bound isoform (mCTLA4), we hypothesized patients benefiting from ipilimumab have higher serum levels of sCTLA4. We found that higher sCTLA4 levels correlated both with response and improved survival in patients treated with ipilimumab in a small patient cohort [patients with (n=9) and without (n=5) clinical benefit]. sCTLA4 levels were statistically higher in ipilimumab-treated patients with response to ipilimumab. In contrast, sCTLA4 levels did not correlate with survival in patients who did not receive ipilimumab (n=11).These preliminary observations provide a previously unrecognized link between serum sCTLA4 levels and response to ipilimumab as well as to improved survival in ipilimumab-treated melanoma patients and a potential mechanism by which ipilimumab functions. [ABSTRACT FROM AUTHOR]

The immunotherapeutic agent ipilimumab has helped address a significant unmet need in the treatment of advanced melanoma. Ipilimumab is a fully human monoclonal antibody that targets cytotoxic T-lymphocyte antigen-4 (CTLA-4), thereby augmenting antitumor immune responses. After decades in which a number of clinical trials were conducted, ipilimumab was the first therapy to improve overall survival in a randomized, controlled phase III trial of patients with advanced melanoma. These results led to the regulatory approval of ipilimumab at 3 mg/kg for the treatment of unresectable or metastatic melanoma. More than 17,000 patients worldwide have received ipilimumab, either as a commercial drug at 3 mg/kg or in clinical trials and expanded access programs at different doses. Consistent with its proposed mechanism of action, the most common toxicities associated with ipilimumab therapy are inflammatory in nature. These immune-related adverse events were mostly reversible when effective treatment guidelines were followed. Importantly, long-term follow-up of patients who received ipilimumab in a phase III trial showed that 24% survived at least two years, and in phase II studies, a proportion of patients survived at least five years. Evaluation of ipilimumab is ongoing in the adjuvant setting for melanoma, and for advanced disease in nonsmall cell lung, small cell lung, prostate, ovarian, and gastric cancers. [ABSTRACT FROM AUTHOR]

Abstract: The current treatment for melanoma with nodal involvement, but without distant metastasis, is surgical excision and lymph node dissection followed by adjuvant therapy. A number of systemic regimens have been evaluated for melanoma patients with a medium or high risk of disease recurrence following surgery. The only agent approved for the adjuvant therapy of melanoma is high-dose interferon (IFN)-α2b, which prolongs relapse-free survival, but its effects on overall survival remain controversial. Its use is also accompanied by significant toxicity. Thus, despite its approval, high-dose IFN-α2b is not always used for the adjuvant therapy of melanoma, particularly in countries other than the United States. Studies aimed at identifying subgroups of patients that have the greatest benefit-to-risk ratio with this regimen are ongoing. Several vaccines have been studied in the adjuvant setting for melanoma, but none has shown superiority to IFN-containing regimens. The GMK ganglioside vaccine, for instance, has actually been shown to be inferior to high-dose IFN-α2b. Therefore, a therapeutic regimen which improves overall survival with a favorable safety profile would be a major advance in the adjuvant therapy of melanoma. One approach that is currently being investigated is the potentiation of antitumour immune responses through blockade of cytotoxic T-lymphocyte antigen-4 (CTLA-4). Here, we provide an overview of the current unmet needs in the adjuvant therapy of melanoma and evaluate the potential of CTLA-4 blockade as a future therapeutic option in this setting. [Copyright &y& Elsevier]

Cancer immunotherapy centers on modulating the host's tumor-directed immune response. One promising approach involves augmentation of cell-mediated immunity by interrupting T-cell pathways responsible for immune down-regulation or tolerance. The discovery of cytotoxic T-lymphocyte antigen-4 (CTLA-4) and its role as a key negative regulator for T cells has prompted efforts to target this signaling molecule to improve cancer therapy. Activation, or 'priming', of naive T cells in response to tumor-cell invasion comprises a dual-signaling mechanism. Signal 1 requires tumor-associated antigen recognition by the T-cell receptor, while signal 2 occurs through binding of CD80 or CD86 (B7.1 of 2) on the antigen presenting cell (APC) with CD28 on the T cell. Importantly, there is a final step responsible for naturally occurring immune regulation; this occurs in response to competitive binding of CD80/CD86 on the APC by CTLA-4 on the T cell. This 'immune checkpoint' interrupts signal 2 and inhibits the activated T cell. Targeting CTLA-4 as an anticancer strategy: Following proof-of-concept studies in animals, fully human anti-CTLA-4 antibodies were developed and 2 are undergoing clinical evaluation. Ipilimumab and tremelimumab have shown promising antitumor activity, initially in patients with advanced melanoma. Class-specific immune-related adverse events (irAEs) were common and mostly transient and/or manageable. These events are thought to be mechanism-of-action-related, indicating immune tolerance is broken; this relation may also explain the association between irAEs and response seen in several trials. Interruption of immune inhibitory pathways via CTLA-4 blockade appears to be a promising strategy for cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Background Pembrolizumab blocks the interaction between PD-1 and its ligands PD-L1 and PD-L2, thereby inducing an antitumor immune response. In a phase I study, pembrolizumab demonstrated promising antitumor activity and acceptable safety in patients with ipilimumab-treated melanoma, leading to accelerated approval in the US. Materials and methods KEYNOTE-002 is a randomized phase 2 study in patients with ipilimumab-refractory melanoma (ie, confirmed PD in the 24 weeks following ≥2 ipilimumab doses) and, if BRAF mutant, previously treated with a BRAF inhibitor. Patients were randomized 1:1:1 to pembrolizumab 2 or 10 mg/kg Q3W or investigator-choice chemotherapy (carboplatin + paclitaxel, carboplatin, paclitaxel, dacarbazine, or temozolomide). Patients with PD confirmed by independent central review could cross over to pembrolizumab treatment after the first 3-month assessment. Primary objective of the interim analysis prespecified to occur after ≥ 270 PFS events (RECIST v1.1, independent central review) was to evaluate the superiority of either pembrolizumab dose over control for PFS at a 1-sided 0.25% significance level (estimated HR 0.66). Results From Nov 2012 to Nov 2013, 540 patients from 12 countries enrolled. Based on central review of a total of 410 PFS events, the HR was 0.57 and 0.50 for pembrolizumab 2 and 10 mg/kg Q3W, respectively, over control (P<0.00001 for both comparisons). The 6-month PFS rate was 34% (95% CI 27%-41%) and 38% (95% CI 31%- 45%) for pembrolizumab 2 and 10 mg/kg, respectively, compared with 16% (95% CI 10%-22%) for the control arm. PFS by investigator assessment was similar to that of central review. The PFS effect was consistent in all subgroups. ORR was 21% at 2 mg/kg, 25% at 10 mg/kg, and 4% in the control arm (P<0.0001 for both comparisons). Median response duration was not reached in either pembrolizumab arm and was 37 weeks in the control arm. Forty-eight percent of patients in the control arm crossed over to pembrolizumab treatment. OS data are not mature (final OS analysis will be performed after 370 deaths have occurred). The safety profile was consistent with that previously observed for pembrolizumab. Despite a decreased therapy duration, rates of grade 3-5 drug-related AEs were numerically higher in the chemotherapy control arm (26%) than in the pembrolizumab 2-mg/kg (11%) and 10-mg/kg (14%) arms. Conclusion Both pembrolizumab doses met prespecified criteria for PFS superiority over the chemotherapy control arm. Pembrolizumab significantly prolongs PFS compared with chemotherapy, approximately doubling the 6-month rate in an ipilimumab-refractory population. [ABSTRACT FROM AUTHOR]