Faculty Bibliography

A 78-year-old man with metastatic malignant melanoma underwent a restaging 18F-FDG PET/CT after initiation of ipilimumab therapy, a Food and Drug Administration-approved human monoclonal antibody targeting CTLA-4. PET/CT demonstrated intense FDG uptake fusing to poorly circumscribed hypodensities throughout the liver. Patient was experiencing high-grade fever, chills, and generalized fatigue at the time of imaging, as well as mildly elevated liver function tests. Patient was subsequently treated with corticosteroids for suspected ipilimumab-induced hepatitis, and the patient rapidly improved clinically. Follow-up PET/CT 2 months later revealed complete resolution of abnormal FDG uptake in the liver, confirming the diagnosis of ipilimumab-induced hepatitis.

The TLR7/8 agonist, Resiquimod has been used as an immune adjuvant in cancer vaccines. We evaluated the safety and immunogenicity of the cancer testis antigen NY-ESO-1 given in combination with Montanide with or without Resiquimod in high risk melanoma patients. In Part I of the study, patients received 100ug full length NY-ESO-1 protein emulsified in 1.25mL Montanide (day 1) followed by topical application of 1000mg of 0.2% Resiquimod gel on days 1 and 3 (Cohort 1) versus days 1, 3, and 5 (Cohort 2) of a 21 day cycle. In Part II, patients were randomized to receive 100ug NY-ESO-1 protein plus Montanide (day 1) followed by topical application of placebo gel (Arm-A; N=8) or 1000mg of 0.2% Resiquimod gel (Arm-B; N=12) using the dosing regimen established in Part I. The vaccine regimens were generally well-tolerated. NY-ESO-1 specific humoral responses were induced or boosted in all patients, many with high titers. In Part II, 16 of 20 patients in both arms had NY-ESO-1-specific CD4+ T cell responses. CD8+ T cell responses were only seen in 3 of 12 patients in Arm B. Patients with TLR7 SNP rs179008 had a greater likelihood of developing NY-ESO-1-specific CD8+ responses. In conclusion, NY-ESO-1 protein in combination with Montanide with or without topical Resiquimod is safe and induces both antibody and CD4+ cell responses in the majority of patients; the small proportion of CD8+ cell responses suggests that the addition of topical Resiquimod to Montanide is not sufficient to induce consistent NY-ESO-1 specific CD8+ cell responses.

BACKGROUND: Surgical management of primary melanoma is curative for most patients with clinically localized disease at diagnosis; however, a substantial number of patients recur and progress to advanced disease. Understanding molecular alterations that influence differential tumor progression of histopathologically similar lesions may lead to improved prognosis and therapies to slow or prevent metastasis. METHODS: We examined microRNA dysregulation by expression profiling of primary melanoma tumors from 92 patients. We screened candidate microRNAs selected by differential expression between recurrent and nonrecurrent tumors or associated with primary tumor thickness (Student's t test, Benjamini-Hochberg False Discovery Rate [FDR] < 0.05), in in vitro invasion assays. We performed in vivo metastasis assays, matrix remodeling experiments, and molecular studies to identify metastasis-regulating microRNAs and their cellular and molecular mechanisms. All statistical tests were two-sided. RESULTS: We identified two microRNAs (hsa-miR-382, hsa-miR-516b) whose expression was lower in aggressive vs nonaggressive primary tumors, which suppressed invasion in vitro and metastasis in vivo (mean metastatic foci: control: 37.9, 95% confidence interval [CI] = 25.6 to 50.2; miR-382: 19.5, 95% CI = 12.2 to 26.9, P = .009; miR-516b: 12.5, 95% CI = 7.7 to 17.4, P < .001, Student's t test). Mechanistically, miR-382 overexpression inhibits extracellular matrix degradation by melanoma cells. Moreover, we identified actin regulators CTTN, RAC1, and ARPC2 as direct targets of miR-382. Depletion of CTTN partially recapitulates miR-382 effects on matrix remodeling, invasion, and metastasis. Inhibition of miR-382 in a weakly tumorigenic melanoma cell line increased tumor progression and metastasis in vivo. CONCLUSIONS: Aberrant expression of specific microRNAs that can functionally impact progression of primary melanoma occurs as an early event of melanomagenesis.

Introduction: Advanced melanoma carries a poor prognosis. Until 2011, the only available US FDA-approved therapies were intravenous dacarbzine and IL-2, neither of which was effective in the majority of patients treated. Ongoing molecular characterization of melanoma has revealed the presence of BRAF mutations in 50% of cases. Targeted therapy against mutant BRAF has emerged as a revolutionary and practice-changing approach in the management of advanced melanoma. Areas covered: Dabrafenib is a selective, ATP-competitive inhibitor of the mutant BRAF kinase and was FDA approved in 2013 as monotherapy for treatment of BRAF V600E-mutated advanced melanoma. Additionally, it has demonstrated efficacy in treatment of melanoma brain metastases and is FDA approved in combination with the MEK inhibitor trametinib for melanomas with a BRAF V600E or V600K mutation. Through a comprehensive literature review, we summarize dabrafenib's place among currently available melanoma therapies, and describe its mechanism of action, pharmacologic properties, adverse events, and the milestone clinical trials leading to dabrafenib's FDA approval. Expert opinion: Dabrafenib is a key first-line therapy for V600-mutated advanced melanoma patients with high tumor burden, brain metastases and significant cancer symptoms, and also serves as an effective salvage therapy. The future of BRAF inhibitor therapy in melanoma is rapidly unfolding, particularly in terms of combination therapy possibilities both with other targeted therapies as well as with immunotherapy.

BackgroundMatrix metalloproteinase-23 (MMP-23) can block the voltage-gated potassium channel Kv1.3, whose function is important for sustained Ca2+ signaling during T cell activation. MMP-23 may also alter T cell activity and phenotype through cleavage of proteins affecting cytokine and chemokine signaling. We therefore tested the hypothesis that MMP-23 can negatively regulate the anti-tumor T cell response in human melanoma.MethodsWe characterized MMP-23 expression in primary melanoma patients who received adjuvant immunotherapy. We examined the association of MMP-23 with the anti-tumor immune response - as assessed by the prevalence of tumor-infiltrating lymphocytes and Foxp3+ regulatory T cells. Further, we examined the association between MMP-23 expression and response to immunotherapy. Considering also an in trans mechanism, we examined the association of melanoma MMP-23 and melanoma Kv1.3 expression.ResultsOur data revealed an inverse association between primary melanoma MMP-23 expression and the anti-tumor T cell response, as demonstrated by decreased tumor-infiltrating lymphocytes (TIL) (P inverted question mark= inverted question mark0.05), in particular brisk TILs (P inverted question mark= inverted question mark0.04), and a trend towards an increased proportion of immunosuppressive Foxp3+ regulatory T cells (P inverted question mark= inverted question mark0.07). High melanoma MMP-23 expression is also associated with recurrence in patients treated with immune biologics (P inverted question mark= inverted question mark0.037) but not in those treated with vaccines (P inverted question mark= inverted question mark0.64). Further, high melanoma MMP-23 expression is associated with shorter periods of progression-free survival for patients receiving immune biologics (P inverted question mark= inverted question mark0.025). On the other hand, there is no relationship between melanoma MMP-23 and melanoma Kv1.3 expression (P inverted question mark= inverted question mark0.27).ConclusionsOur data support a role for MMP-23 as a potential immunosuppressive target in melanoma, as well as a possible biomarker for informing melanoma immunotherapies.

PURPOSE: The antibody-drug conjugate glembatumumab vedotin links a fully human immunoglobulin G2 monoclonal antibody against the melanoma-related glycoprotein NMB (gpNMB) to the potent cytotoxin monomethyl auristatin E. This study evaluated the safety and activity of glembatumumab vedotin in patients with advanced melanoma. PATIENTS AND METHODS: Patients received glembatumumab vedotin every 3 weeks (schedule 1) in a dose escalation and phase II expansion at the maximum-tolerated dose (MTD). Dosing during 2 of 3 weeks (schedule 2) and weekly (schedule 3) was also assessed. The primary end points were safety and pharmacokinetics. The secondary end points included antitumor activity, gpNMB expression, and immunogenicity. RESULTS: One hundred seventeen patients were treated using schedule 1 (n = 79), schedule 2 (n = 15), or schedule 3 (n = 23). The MTDs were 1.88, 1.5, and 1.0 mg/kg for schedules 1, 2, and 3, respectively. Grade 3/4 treatment-related toxicities that occurred in two or more patients included rash, neutropenia, fatigue, neuropathy, arthralgia, myalgia, and diarrhea. Three treatment-related deaths (resulting from pneumococcal sepsis, toxic epidermal necrolysis, and renal failure) occurred at doses exceeding the MTDs. In the schedule 1 phase II expansion cohort (n = 34), five patients (15%) had a partial response and eight patients (24%) had stable disease for >/= 6 months. The objective response rate (ORR) was 2 of 6 (33%) for the schedule 2 MTD and 3 of 12 (25%) for the schedule 3 MTD. Rash was correlated with a greater ORR and improved progression-free survival. CONCLUSION: Glembatumumab vedotin is active in advanced melanoma. The schedule 1 MTD (1.88 mg/kg once every 3 weeks) was associated with a promising ORR and was generally well tolerated. More frequent dosing was potentially associated with a greater ORR but increased toxicity.