Katharina C. Kaehler

Genomic correlates of response to CTLA-4 blockade in metastatic melanoma

Is cancer immunotherapy a private affair? Immune checkpoint blockade, a relatively new cancer treatment, substantially extends the survival of a subset of patients. Previous work has shown that patients whose tumors harbor the largest number of mutations—and thus produce a large number of “neoantigens” recognized as foreign by the immune system—are most likely to benefit. Expanding on these earlier studies, Van Allen et al. studied over 100 patients with melanoma and found a similar correlation (see the Perspective by Gubin and Schreiber). There was no evidence, however, that specific neoantigen sequences were shared by patients who responded. Science, this issue p. 207, see also p. 158 Melanoma patients who respond to immunotherapy do not appear to share common tumor neoantigens. [Also see Perspective by Gubin and Schreiber ] Monoclonal antibodies directed against cytotoxic T lymphocyte–associated antigen-4 (CTLA-4), such as ipilimumab, yield considerable clinical benefit for patients with metastatic melanoma by inhibiting immune checkpoint activity, but clinical predictors of response to these therapies remain incompletely characterized. To investigate the roles of tumor-specific neoantigens and alterations in the tumor microenvironment in the response to ipilimumab, we analyzed whole exomes from pretreatment melanoma tumor biopsies and matching germline tissue samples from 110 patients. For 40 of these patients, we also obtained and analyzed transcriptome data from the pretreatment tumor samples. Overall mutational load, neoantigen load, and expression of cytolytic markers in the immune microenvironment were significantly associated with clinical benefit. However, no recurrent neoantigen peptide sequences predicted responder patient populations. Thus, detailed integrated molecular characterization of large patient cohorts may be needed to identify robust determinants of response and resistance to immune checkpoint inhibitors.

The price of tumor control: an analysis of rare side effects of anti-CTLA-4 therapy in metastatic melanoma from the ipilimumab network

Background Ipilimumab, a cytotoxic T-lymphocyte antigen-4 (CTLA-4) blocking antibody, has been approved for the treatment of metastatic melanoma and induces adverse events (AE) in up to 64% of patients. Treatment algorithms for the management of common ipilimumab-induced AEs have lead to a reduction of morbidity, e.g. due to bowel perforations. However, the spectrum of less common AEs is expanding as ipilimumab is increasingly applied. Stringent recognition and management of AEs will reduce drug-induced morbidity and costs, and thus, positively impact the cost-benefit ratio of the drug. To facilitate timely identification and adequate management data on rare AEs were analyzed at 19 skin cancer centers. Methods and Findings Patient files (n = 752) were screened for rare ipilimumab-associated AEs. A total of 120 AEs, some of which were life-threatening or even fatal, were reported and summarized by organ system describing the most instructive cases in detail. Previously unreported AEs like drug rash with eosinophilia and systemic symptoms (DRESS), granulomatous inflammation of the central nervous system, and aseptic meningitis, were documented. Obstacles included patientś delay in reporting symptoms and the differentiation of steroid-induced from ipilimumab-induced AEs under steroid treatment. Importantly, response rate was high in this patient population with tumor regression in 30.9% and a tumor control rate of 61.8% in stage IV melanoma patients despite the fact that some patients received only two of four recommended ipilimumab infusions. This suggests that ipilimumab-induced antitumor responses can have an early onset and that severe autoimmune reactions may reflect overtreatment. Conclusion The wide spectrum of ipilimumab-induced AEs demands doctor and patient awareness to reduce morbidity and treatment costs and true ipilimumab success is dictated by both objective tumor responses and controlling severe side effects.

An Exploratory Study of Systemic Administration of the Toll-like Receptor-7 Agonist 852A in Patients with Refractory Metastatic Melanoma

Purpose: A topical Toll-like receptor 7 (TLR7) agonist induces regression of cutaneous melanocytic neoplasms. We explored antitumor activity of a systemically administered TLR7 agonist, 852A, in patients with metastatic melanoma. Experimental Design: We undertook a phase II, multicenter, open-label study in patients with chemotherapy-refractory metastatic melanoma. Patients received i.v. 852A, starting at 0.6 mg/m2 and increasing to 0.9 mg/m2 based on tolerance, thrice per week for 12 weeks. Clinical response was determined by Response Evaluation Criteria in Solid Tumors. Immune effects of 852A were monitored by measuring serum type I IFN and IP-10 together with assessment of immune cell markers in peripheral blood. Results: Twenty-one patients were enrolled. Thirteen patients completed the initial 12-week treatment cycle, with two discontinuing for adverse events considered to be possibly related to study drug. Four (19%) patients had disease stabilization for >100 days. One patient had a partial remission after two treatment cycles, but progressed during the third. Dose-limiting toxicity was observed in two patients. Serum type I IFN and IP-10 increased in most patients on 852A administration. Serum type I IFN increases were greater after dosing with 852A 0.9 mg/m2 than after 0.6 mg/m2 (P = 0.009). The maximal increase in IP-10 compared with baseline correlated with the maximal increase in type I IFN (P = 0.003). In the eight patients with immune cell marker data, CD86 expression on monocytes increased significantly post-first dose (P = 0.007). Conclusion: Intravenous 852A was well tolerated and induced systemic immune activation that eventually resulted in prolonged disease stabilization in some patients with stage IV metastatic melanoma who had failed chemotherapy.

Multicenter phase II trial of the histone deacetylase inhibitor pyridylmethyl-N-{4-((2-aminophenyl)-carbamoyl)-benzyl}- carbamate in pretreated metastatic melanoma

Systemic treatment of metastatic melanoma is of low efficacy, and new therapeutic strategies are needed. Histone deacetylase inhibitors are supposed to restore the expression of tumor suppressor genes and induce tumor cell differentiation, growth arrest, and apoptosis. This study was aimed to evaluate the efficacy, safety, and pharmacokinetics of the histone deacetylase inhibitor pyridylmethyl-N-{4-[(2-aminophenyl)-carbamoyl]-benzyl}-carbamate (MS-275) in patients with pretreated metastatic melanoma. Patients with unresectable AJCC stage IV melanoma refractory to at least one earlier systemic therapy were randomized to receive MS-275 3 mg biweekly (days 1+15, arm A) or 7 mg weekly (days 1+8+15, arm B), in 4-week cycles. The primary study endpoint was objective tumor response, secondary endpoints were safety and time-to-progression. On the basis of Simons two-stage design, the study initially allowed an entry of 14 patients per arm; if there was at least one responder, additional 33 patients were to be enrolled. Among 28 patients enrolled, no objective response was detected. Four (29%) patients in arm A and three (21%) patients in arm B showed disease stabilizations. Median time-to-progression was comparable in both arms with 55.5 versus 51.5 days, respectively; median overall survival was 8.84 months. Toxicity was mild to moderate with nausea (39%) and hypophosphatemia (29%) as the most frequently reported events. No treatment-related serious adverse events occurred. Single-agent treatment with MS-275 was well-tolerated and showed long-term tumor stabilizations, but no objective responses in pretreated metastatic melanoma. Further evaluation of MS-275 in combination schedules is warranted.

Long-term survival analysis in metastatic melanoma: serum S100B is an independent prognostic marker and superior to LDH.

Background: The prognosis of metastatic melanoma is poor. The purpose of this study was to perform a long-term survival analysis on patients with advanced melanoma to determine clinical and laboratory prognostic factors for treatment outcome and long-term survival. The prognostic importance of S100B serum levels on overall survival compared to lactate dehydrogenase (LDH) was evaluated. Patients and Methods: The medical records of 105 AJCC (American Joint Committee on Cancer) stage IV melanoma patients from 1994 to 2001 were analyzed retrospectively. Median time to progression and overall survival were assessed. Univariate and multivariate analysis were performed to determine prognostic factors. Results: 86 (81.9%) of the 105 patients died during the observation period. In univariate analysis, pre-therapeutic LDH and S100B levels in serum samples (p = 0.01 and p = 0.002, respectively), tumor stage (AJCC IVa–IVc, p = 0.005), and response to the firstline therapy (p < 0.001) were found to be significant prognostic markers. However, in the multivariate analysis, pre-therapeutic S100B serum levels (p = 0.005, odds ratio (OR): 2.22, confidence interval (CI): 1.22–4.1) as well as presence of brain metastases (p = 0.009, OR: 5.08, CI: 1.51–17.05) were the only independent prognostic factors for overall survival. Conclusion: In metastatic melanoma, S100B is a strong prognostic factor for overall and long-term survival, and superior to LDH.

Upstream mitogen-activated protein kinase (MAPK) pathway inhibition: MEK inhibitor followed by a BRAF inhibitor in advanced melanoma patients☆

BRAF-mutant melanoma can be successfully treated by BRAF kinase inhibitors (BRAFi) and MEK kinase inhibitors (MEKi). However, the administration of BRAFi followed by MEKi did not generate promising response rate (RR). The purpose of this investigation was to evaluate the time to progression (TTP) with a mitogen-activated protein kinase (MAPK) pathway upstream inhibition strategy in BRAF mutated melanoma patients. BRAF mutation positive metastatic melanoma patients were identified within the Dermatology Cooperative Oncology Group (DeCOG) network and were treated first with a MEKi and upon progression with a selective BRAFi. A total of 23 melanoma patients (six females, 17 males, aged 47-80 years) were retrospectively analysed for TTP. The total median TTP was 8.9 months. The median TTP for MEKi was 4.8 (1.2-23.2) and subsequent for BRAFi 4.5 (1.2-15.7) months, respectively. A higher RR for MEKi (39%, nine partial responses and 0 complete responses) than previously reported was observed. Our analysis suggests that the reversed inhibition of the MAPK pathway is feasible in BRAF mutated melanoma. The median TTP (8.9 months) is close to the promising BRAF- and MEKi combination therapy (median progression-free survival (PFS) 9.4 months). The total treatment duration of the MAPK inhibition when a MEKi is administered first is similar compared to the reversed sequence, but TTP shifts in favour to the MEKi. This approach is feasible with reasonable tolerability. This clinical investigation encourages further studies in prospective clinical trials to define the optimal treatment schedule for the MAPK pathway inhibition and should be accompanied by molecular monitoring using repeated biopsies.

Sorafenib and pegylated interferon-α2b in advanced metastatic melanoma: a multicenter phase II DeCOG trial

BACKGROUND The combination of sorafenib, a multikinase inhibitor, and pegylated interferon-α2b (Peg-IFN-α2b) could potentially lead to an improved antitumoral response. Previously, combinations of interferon and sorafenib have been used in renal cell cancer. PATIENTS AND METHODS Patients with stage IV metastatic melanoma and no previous systemic therapies apart from adjuvant immunotherapy received Peg-IFN-α2b 3 μg/kg once per week, and sorafenib 400-mg b.i.d. for a minimum of 8 weeks. The primary study end point was disease control rate (DCR). RESULTS Between February 2008 and February 2009, 55 patients were enrolled with a median age of 64 years (20-85). At 8 weeks, 2 patients (3.6%) had a partial response (PR) and 14 patients a stable disease (25.5%), for a DCR of 29.1% in the intention-to-treat (ITT) population. The median progression-free survival in the ITT population was 2.47 months (95% confidence interval 1.22-3.72 months). The toxicity of sorafenib and Peg-IFN-α2b combination was characterized by mainly hematological side-effects, including one treatment-related bleeding complication with a fatal outcome. Other grade 3/4 toxic effects were fatigue and flu-like symptoms. CONCLUSION The combination of sorafenib and Peg-IFN-α2b showed modest clinical activity and some serious side-effects including fatal bleeding complications.

Anti-CTLA-4 therapy-related autoimmune hypophysitis in a melanoma patient

Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) is an immunoregulatory molecule expressed by activated T cells and resting CD4+CD25 T cells. In patients with advanced melanoma, anti-CTLA-4 antibody therapy achieves cancer regression in 15% of patients. Treatment may be associated with grade III/IV autoimmune manifestations that included dermatitis, enterocolitis, hepatitis, uveitis, and rarely hypophysitis. Many of these toxicities require and respond to brief courses of high-dose corticosteroids. We report on a case of autoimmune hypophysitis with severe clinical symptoms that resolved rapidly after treatment with steroids. It is important to consider both autoimmune hypophysitis and brain metastasis in the differential diagnosis of melanoma patients receiving CTLA-4 blockade who present this constellation of symptoms.

Temozolomide plus pegylated interferon alfa-2b as first-line treatment for stage IV melanoma: a multicenter phase II trial of the Dermatologic Cooperative Oncology Group (DeCOG)

BACKGROUND Combination of temozolomide (TMZ) with nonpegylated interferon alfa is associated with increased efficacy in terms of response rates compared with monotherapy. A multicenter phase II study was carried out to assess the activity and toxicity of TMZ plus pegylated interferon alfa-2b (peg-IFNalpha-2b), hypothesizing improved efficacy due to modified pharmacokinetic properties of the novel interferon (IFN) formulation. PATIENTS AND METHODS In all, 124 patients with stage IV melanoma without prior chemotherapy and no cerebral metastases were treated with 100 mug peg-IFNalpha-2b s.c. per week and oral TMZ 200 mg/m(2) (days 1-5, every 28 days). Primary study end point was objective response, and secondary end points were overall and progression-free survival (PFS) and safety. RESULTS In all, 116 patients were assessable for response: 2 (1.7%) had a complete response and 19 (16.4%) a partial response (overall response rate 18.1%). Of total, 25.0% achieved disease stabilization and 56.9% progressed. Overall survival was 9.4 months; PFS was 2.8 months. Grade 3/4 thrombocytopenia occurred in 20.7% and grade 3/4 leukopenia in 23.3%. CONCLUSIONS The efficacy of TMZ plus peg-IFNalpha-2b in this large phase II study is moderate and comparable to published results of the combination of TMZ with non-peg-IFN. Likewise, the safety profile of peg-IFNalpha-2b seems to be similar to non-peg-IFN when combined with TMZ.

Electrochemotherapy in Symptomatic Melanoma Skin Metastases: Intraindividual Comparison with Conventional Surgery

Electrochemotherapy is a procedure that exposes cancer cells to a sequence of brief electrical pulses of controlled voltage and duration, increasing cell permeability and enhancing the uptake of cytotoxic drugs by tumor cells (Figure 1). The intracellular concentration and thereby the toxicity of bleomycin and cisplatin can be increased up to 10,000 times and 80 times, respectively. Previous in vitro studies have demonstrated that electroporation can increase the efficacy of cytotoxic drugs. In a clinical trial, electroporation induced partial remission in 14% and complete remission in 66% of the treated tumors.