Activity of the Heat Shock Protein 90 Inhibitor Ganetespib in Melanoma

Heat shock protein 90 (HSP90) is involved in the regulation of diverse biological processes such as cell signaling, proliferation and survival, and has been recently recognized as a potential target for cancer therapy. Ganetespib is a potent ATP competitive inhibitor of HSP90. Ganetespib downregulated the expression of multiple signal transducing molecules including EGFR, IGF-1R, c-Met, Akt, B-RAF and C-RAF, resulting in pronounced decrease in phosphorylation of Akt and Erk1/2 in a panel of five cutaneous melanoma cell lines including those harboring B-RAF and N-RAS mutations. Ganetespib exhibited potent antiproliferative activity on all five of these cell lines, with IC50 values between 37.5 and 84 nM. Importantly, Ganetespib is active on B-RAF mutated melanoma cells that have acquired resistance to B-RAF inhibition. Ganetespib induced apoptosis and cell cycle arrest at G1 and/or G2/M phase. Ganetespib induced cell cycle arrest was accompanied by altered expression of cyclin-dependent kinase inhibitor (CDKI) p21Cip1 and p27Kip1, cyclins B1, D1 and E, and/or cyclin-dependent kinases 1, 2 and 4. HSP90 is functionally important for melanoma cells and HSP90 inhibitors such as ganetespib could potentially be effective therapeutics for melanoma with various genetic mutations and acquired resistance to B-RAF inhibition

The Protein Kinase C Inhibitor Enzastaurin Exhibits Antitumor Activity against Uveal Melanoma

GNAQ mutations at codon 209 have been recently identified in approximately 50% of uveal melanomas (UM) and are reported to be oncogenic through activating the MAPK/Erk1/2 pathway. Protein kinase C (PKC) is a component of signaling from GNAQ to Erk1/2. Inhibition of PKC might regulate GNAQ mutation-induced Erk1/2 activation, resulting in growth inhibition of UM cells carrying GNAQ mutations. UM cells carrying wild type or mutant GNAQ were treated with the PKC inhibitor enzastaurin. Effects on proliferation, apoptosis, and signaling events were evaluated. Enzastaurin downregulated the expression of several PKC isoforms including PKCβII PKCθ, PKCε and/or their phosphorylation in GNAQ mutated cells. Downregulation of these PKC isoforms in GNAQ mutated cells by shRNA resulted in reduced viability. Enzastaurin exhibited greater antiproliferative effect on GNAQ mutant cells than wild type cells through induction of G1 arrest and apoptosis. Enzastaurin-induced G1 arrest was associated with inhibition of Erk1/2 phosphorylation, downregulation of cyclin D1, and accumulation of cyclin dependent kinase inhibitor p27Kip1. Furthermore, enzastaurin reduced the expression of antiapoptotic Bcl-2 and survivin in GNAQ mutant cells. Inhibition of Erk1/2 phosphorylation with a MEK specific inhibitor enhanced the sensitivity of GNAQ wild type cells to enzastaurin, accompanied by p27Kip1 accumulation and/or inhibition of enzastaurin-induced survivin and Bcl-2 upregulation. PKC inhibitors such as enzastaurin have activity against UM cells carrying GNAQ mutations through inhibition of the PKC/Erk1/2 pathway and induction of G1 arrest and apoptosis. Inhibition of the PKC pathway provides a basis for clinical investigation in patients with UM

Antitumour activity of pembrolizumab in advanced mucosal melanoma: a post-hoc analysis of KEYNOTE-001, 002, 006.

BackgroundMucosal melanoma is an aggressive melanoma with poor prognosis. We assessed efficacy of pembrolizumab in patients with advanced mucosal melanoma in KEYNOTE-001 (NCT01295827), -002 (NCT01704287), and -006 (NCT01866319).MethodsPatients received pembrolizumab 2 mg/kg every 3 weeks (Q3W) or 10 mg/kg Q2W or Q3W. Response was assessed by independent central review per RECIST v1.1.Results1567 patients were treated and 84 (5%) had mucosal melanoma. Fifty-one of 84 were ipilimumab-naive. In patients with mucosal melanoma, the objective response rate (ORR) was 19% (95% CI 11-29%), with median duration of response (DOR) of 27.6 months (range 1.1 + to 27.6). Median progression-free survival (PFS) was 2.8 months (95% CI 2.7-2.8), with median overall survival (OS) of 11.3 months (7.7-16.6). ORR was 22% (95% CI 11-35%) and 15% (95% CI 5-32%) in ipilimumab-naive and ipilimumab-treated patients.ConclusionPembrolizumab provides durable antitumour activity in patients with advanced mucosal melanoma regardless of prior ipilimumab

Inhibition of Immune Checkpoints and Vascular Endothelial Growth Factor as Combination Therapy for Metastatic Melanoma: An Overview of Rationale, Preclinical Evidence, and Initial Clinical Data

The role of angiogenesis as a mediator of immune regulation in the tumor microenvironment has recently come into focus. Furthermore, emerging evidence indicates that immunotherapy can lead to immune-mediated vasculopathy in the tumor, suggesting that the tumor vasculature may be an important interface between the tumor-directed immune response and the cancer itself. The advent of immune checkpoint inhibition as an effective immunotherapeutic strategy for many cancers has led to a better understanding of this interface. While the inhibition of angiogenesis through targeting of vascular endothelial growth factor (VEGF) has been used successfully for the treatment of cancer for many years, the mechanisms of its anti-tumor activity remain poorly understood. Initial studies of the complex relationship between angiogenesis, VEGF signaling and the immune system suggest that the combination of immune checkpoint blockade with angiogenesis inhibition has potential. While the majority of this work has been performed in metastatic melanoma, immunotherapy is rapidly showing promise in a broad range of malignancies and efforts to enhance immunotherapy will broadly impact the future of oncology. Here, we review the preclinical rationale and clinical investigations of combined angiogenesis inhibition and immunotherapy/immune checkpoint inhibition as a potentially promising combinatorial approach for cancer treatment

Immunity to the Melanoma Inhibitor of Apoptosis Protein (ML-IAP; livin) in Patients with Malignant Melanoma

Therapeutic targeting of melanoma antigens frequently focuses on the melanocyte differentiation or cancer-testis families. Antigen-loss variants can often result, as these antigens are not critical for tumor cell survival. Exploration of functionally relevant targets has been limited. The melanoma inhibitor of apoptosis protein (ML-IAP; livin) is overexpressed in melanoma, contributing to disease progression and treatment resistance. Improved understanding of the significance of ML-IAP immune responses in patients has possible therapeutic applications. We found ML-IAP frequently expressed in melanoma metastases by immunohistochemistry. To assess spontaneous immunity to ML-IAP, an overlapping peptide library representing full-length protein was utilized to screen cellular responses in stage I–IV patients and healthy controls by ELISPOT. A broad array of $CD4^+$ and $CD8^+$ cellular responses against ML-IAP was observed with novel class I and class II epitopes identified. Specific HLA-A*0201 epitopes were analyzed further for frequency of reactivity. The generation of specific $CD4^+$ and cytotoxic T cells revealed potent functional capability including cytokine responsiveness to melanoma cell lines and tumor cell killing. In addition, recombinant ML-IAP protein used in an ELISA demonstrated high titer antibody responses in a subset of patients. Several melanoma patients who received CTLA-4 blockade with ipilimumab developed augmented humoral immune responses to ML-IAP as a function of treatment which was associated with beneficial clinical outcomes. High frequency immune responses in melanoma patients, associations with favorable treatment outcomes, and its essential role in melanoma pathogenesis support the development of ML-IAP as a disease marker and therapeutic target

Efficacy of PD-1 & PD-L1 inhibitors in older adults: a meta-analysis

Background: Immune checkpoint inhibitors targeting PD-1/PD-L1 pathway demonstrated promising activities in variety of malignancies, however little is known regarding their efficacy in adults aged ≥65 years. Methods: We conducted a systematic review and a study-level meta-analysis to explore efficacy of ICIs based on age, younger vs older than 65 years. We included in this analysis randomized controlled phase II or III studies in patients with metastatic solid tumors that compared efficacy of PD-1 or PD-L1 inhibitors to a non-PD-1/PD-L1 inhibitor. Aggregated estimates of overall survival (OS) and progression-free survival (PFS) are based on random/mixed effects (RE) models to allow for heterogeneity between the studies. Results: Initial search identified 53 articles, 17 were randomized controlled trials that compared nivolumab, pembrolizumab or atezolizumab to chemotherapy or targeted therapy. Only 9 trials reported hazard ratiios (HR) for OS based on age and were included in this meta-analysis. Out of those studies seven reported HR for PFS but only 4 studies included subgroup-analysis based on age for PFS. The overall estimated random-effects HR for death was 0.64 with 95% CI of 0.54–0.76 in patients ≥65 years vs. 0.68 with 95% CI of 0.61–0.75 in patients < 65 years. The overall estimated random-effects for HR for progression was 0.74 with 95% CI of 0.60–0.92 in patients ≥65 years vs. 0.73 with 95% CI of 0.61–0.88 in patients < 65 years. Conclusions: PD-1 (nivolumab and pembrolizumab) and PD-L1 (atezolizumab) inhibitors had comparable efficacy in adults younger vs ≥ 65 years

Neurologic Serious Adverse Events Associated with Nivolumab Plus Ipilimumab or Nivolumab Alone in Advanced Melanoma, Including a Case Series of Encephalitis

BackgroundDespite unprecedented efficacy across multiple tumor types, immune checkpoint inhibitor therapy is associated with a unique and wide spectrum of immune‐related adverse events (irAEs), including neurologic events ranging from mild headache to potentially life‐threatening encephalitis. Here, we summarize neurologic irAEs associated with nivolumab and ipilimumab melanoma treatment, present cases of treatment‐related encephalitis, and provide practical guidance on diagnosis and management.MethodsWe searched a Global Pharmacovigilance and Epidemiology database for neurologic irAEs reported over an 8‐year period in patients with advanced melanoma receiving nivolumab with or without ipilimumab from 12 studies sponsored by Bristol‐Myers Squibb. Serious neurologic irAEs were reviewed, and relationship to nivolumab or ipilimumab was assigned.ResultsIn our search of 3,763 patients, 35 patients (0.93%) presented with 43 serious neurologic irAEs, including neuropathy (n = 22), noninfective meningitis (n = 5), encephalitis (n = 6), neuromuscular disorders (n = 3), and nonspecific adverse events (n = 7). Study drug was discontinued (n = 20), interrupted (n = 8), or unchanged (n = 7). Most neurologic irAEs resolved (26/35 patients; 75%). Overall, median time to onset was 45 days (range 1–170) and to resolution was 32 days (2–809+). Median time to onset of encephalitis was 55.5 days (range 18–297); four cases resolved and one was fatal.ConclusionBoth oncologists and neurologists need to be aware of signs and symptoms of serious but uncommon neurologic irAEs associated with checkpoint inhibitors. Prompt diagnosis and management using an established algorithm are critical to minimize serious complications from these neurologic irAEs.Implications for PracticeWith increasing use of checkpoint inhibitors in cancer, practicing oncologists need to be aware of the potential risk of neurologic immune‐related adverse events and be able to provide prompt treatment of this uncommon, but potentially serious, class of adverse events. We summarize neurologic adverse events related to nivolumab alone or in combination with ipilimumab in patients with advanced melanoma from 12 studies and examine in depth 6 cases of encephalitis. We also provide input and guidance on the existing neurologic adverse events management algorithm for nivolumab and ipilimumab.Melanoma is a particularly immunogenic cancer, and immune checkpoint inhibitors have been extensively studied in this tumor type. This review focuses on the incidence of serious neurologic immune‐related adverse events, specifically encephalitis, in patients with advanced melanoma treated with nivolumab alone or in sequence or combination with ipilimumab. Practical guidance is provided for the diagnosis and management of treatment‐related encephalitis associated with nivolumab and ipilimumab.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139998/1/onco12130.pd

Proton Pump Inhibitor Use and Efficacy of Nivolumab and Ipilimumab in Advanced Melanoma

The impact of proton pump inhibitors (PPIs) on clinical outcomes with first-line immune checkpoint inhibitors (ICIs) in patients with metastatic melanoma was previously analyzed in the phase II study, CheckMate 069. This retrospective analysis utilized data from three phase II/III studies of first-line ICI therapy in untreated advanced melanoma: CheckMate 066, 067, and 069. All randomized patients with PPI use ≤ 30 days before initiating study treatment were included in the PPI-use subgroup. Possible associations between baseline PPI use and efficacy were evaluated within each treatment arm of each study using multivariable modeling. Approximately 20% of 1505 randomized patients across the studies reported baseline PPI use. The median follow-up was 52.6–58.5 months. Objective response rate (ORR), progression-free survival (PFS), and overall survival analyses provided insufficient evidence of a meaningful association between PPI use and efficacy outcomes with nivolumab-plus-ipilimumab, nivolumab, or ipilimumab therapy. In five of the six ICI treatment arms, 95% confidence intervals for odds ratios or hazard ratios traversed 1. Significant associations were observed in the CheckMate 069 combination arm between PPI use and poorer ORR and PFS. This multivariable analysis found insufficient evidence to support meaningful associations between PPI use and ICI efficacy in patients with advanced melanoma

The role of whole brain radiation therapy in the management of melanoma brain metastases

Background: Brain metastases are common in patients with melanoma, and optimal management is not well defined. As melanoma has traditionally been thought of as “radioresistant,” the role of whole brain radiation therapy (WBRT) in particular is unclear. We conducted this retrospective study to identify prognostic factors for patients treated with stereotactic radiosurgery (SRS) for melanoma brain metastases and to investigate the role of additional up-front treatment with whole brain radiation therapy (WBRT). Methods: We reviewed records of 147 patients who received SRS as part of initial management of their melanoma brain metastases from January 2000 through June 2010. Overall survival (OS) and time to distant intracranial progression were calculated using the Kaplan-Meier method. Prognostic factors were evaluated using the Cox proportional hazards model. Results: WBRT was employed with SRS in 27% of patients and as salvage in an additional 22%. Age at SRS > 60 years (hazard ratio [HR] 0.64, p = 0.05), multiple brain metastases (HR 1.90, p = 0.008), and omission of up-front WBRT (HR 2.24, p = 0.005) were associated with distant intracranial progression on multivariate analysis. Extensive extracranial metastases (HR 1.86, p = 0.0006), Karnofsky Performance Status (KPS) ≤ 80% (HR 1.58, p = 0.01), and multiple brain metastases (HR 1.40, p = 0.06) were associated with worse OS on univariate analysis. Extensive extracranial metastases (HR 1.78, p = 0.001) and KPS (HR 1.52, p = 0.02) remained significantly associated with OS on multivariate analysis. In patients with absent or stable extracranial disease, multiple brain metastases were associated with worse OS (multivariate HR 5.89, p = 0.004), and there was a trend toward an association with worse OS when up-front WBRT was omitted (multivariate HR 2.56, p = 0.08). Conclusions: Multiple brain metastases and omission of up-front WBRT (particularly in combination) are associated with distant intracranial progression. Improvement in intracranial disease control may be especially important in the subset of patients with absent or stable extracranial disease, where the competing risk of death from extracranial disease is low. These results are hypothesis generating and require confirmation from ongoing randomized trials