Randomized phase II trial of sorafenib with temsirolimus or tipifarnib in untreated metastatic melanoma (S0438)

PURPOSE

Signaling pathway stimulation by activating mutations of oncogenes occurs in most melanomas and can provide excellent targets for therapy, but the short-term therapeutic success is limited by intrinsic and acquired resistance. The mitogen-activated protein kinase and phosphoinositide 3-kinase/AKT/mTOR pathways are activated in most cutaneous melanomas. The purpose of this trial was to prospectively evaluate 2 molecularly targeted drug combinations in patients with untreated metastatic melanoma.

EXPERIMENTAL DESIGN

This randomized phase II study enrolled patients between May 2008 and November 2009 with nonocular melanoma, no prior systemic chemotherapy, and no history of brain metastasis. Arm A received oral sorafenib 200 mg twice daily plus i.v. temsirolimus 25 mg weekly; and arm B received oral sorafenib 400 mg every morning, 200 mg every night daily plus oral tipifarnib 100 mg twice daily, 3 weeks of every 4. The primary objectives were to evaluate progression-free survival (PFS), objective response rate, and toxicity for the 2 regimens.

RESULTS

On arm A (63 evaluable patients), the median PFS was 2.1 months and median overall survival (OS) was 7 months. Three patients achieved partial response (PR). Thirty-nine evaluable patients were accrued to arm B, which closed after first-stage accrual; the median PFS was 1.8 months and OS was 7 months, with 1 patient achieving PR.

CONCLUSIONS

The combinations of molecularly targeted agents tested did not show sufficient activity to justify further use. Newer agents and improved patient selection by characterization of the molecular targets in individual tumors show great promise and should be incorporated into future studies, along with appropriate laboratory correlates.

Targeting angiogenesis in melanoma: prospects for the future

Angiogenesis has been identified as a relevant target for melanoma experimental therapeutics, based on preclinical and clinical studies. A variety of angiogenesis inhibitors are currently being tested in both metastatic and adjuvant melanoma clinical trials. To date, the most promising evidence of benefit is based on a statistically nonsignificant trend in survival gain reported in a randomized phase II trial combining bevacizumab, a monoclonal antibody targeting vascular endothelial growth factor, with cytotoxic chemotherapy. Larger phase III studies are required to determine the true extent of clinical benefit with this class of agents. Key to these clinical trials is the need to include translational endpoints, since correlation of biological and clinical data will provide the opportunity to identify biomarkers predictive of treatment response. These biological studies will also aid our, as yet, poor understanding of the mechanism of action of angiogenesis inhibitors, as well as drug-related side effects. Finally, if these trials show meaningful clinical benefit, then careful consideration will need to be given when designing second-generation trials, in the light of novel gene-directed therapies currently showing promise in melanoma.

Two drug interaction studies of sirolimus in combination with sorafenib or sunitinib in patients with advanced malignancies

PURPOSE

Sirolimus is the prototypical mTOR inhibitor. Sorafenib and sunitinib are small molecule inhibitors of multiple kinases including VEGF receptor (VEGFR) kinases. These agents have different mechanisms of action, providing a strong rationale for combination.

EXPERIMENTAL DESIGN

Patients with advanced cancer were assigned to receive either sirolimus or the VEGFR inhibitor alone for a 2-week lead-in period, followed by combination therapy. The primary end point of each trial was to determine whether a drug interaction exists between sirolimus and either sorafenib or sunitinib, as defined by a difference in C(max) for each drug alone compared with its C(max) during combination therapy.

RESULTS

The sorafenib and sunitinib trials enrolled 34 and 23 patients, respectively. There were no clinically significant differences in C(max) for any of the drugs alone compared with the C(max) during combination therapy. Toxicity profiles were similar to those expected for each drug alone. One patient with adrenal cortical cancer had a partial response to sirolimus and sunitnib.

CONCLUSIONS

Sirolimus can be safely combined with sorafenib or sunitinib. Our trial design is feasible and informative in screening for potential drug-drug interactions, using a relatively small number of patients and limited pharmacokinetic sampling.

Targeted therapy for melanoma: a primer

Melanoma is the most aggressive form of skin cancer. Unfortunately, despite recent improvements for some solid tumors, the prevalence and mortality of melanoma continue to increase. The identification of activating mutations in melanoma, combined with a growing appreciation of the different pattern of genetic changes in the anatomically defined melanoma subtypes, has become the focus of a concerted effort to translate these discoveries into personalized therapeutic approaches for this disease. This article reviews the known mutations, amplifications, and deletions in kinase signaling pathways that have been implicated in melanoma; the prevalence of these genetic events in clinicopathologically defined melanoma subtypes; and the results of clinical trials that use targeted therapy approaches to block aberrantly activated pathways resulting from these mutations. The challenges that must be overcome to achieve improved outcomes with targeted therapies in melanoma in the future are also discussed.

Utilizing targeted cancer therapeutic agents in combination: novel approaches and urgent requirements

The rapid development of new therapeutic agents that target specific molecular pathways involved in tumour cell proliferation provides an unprecedented opportunity to achieve a much higher degree of biochemical specificity than previously possible with traditional chemotherapeutic anticancer agents. However, the lack of specificity of these established chemotherapeutic drugs allowed a relatively straightforward approach to their use in combination therapies. Developing a paradigm for combining new, molecularly targeted agents, on the other hand, is substantially more complex. The abundance of molecular data makes it possible, at least in theory, to predict how such agents might interact across crucial growth control networks. Initial strategies to examine molecularly targeted agent combinations have produced a small number of successes in the clinic. However, for most of these combination strategies, both in preclinical models and in patients, it is not clear whether the agents being combined actually hit their targets to induce growth inhibition. Here, we consider the initial approach of the US National Cancer Institute (NCI) to the evaluation of combinations of molecularly targeted anticancer agents in patients and provide a description of several new approaches that the NCI has initiated to improve the effectiveness of combination-targeted therapy for cancer.

Bevacizumab and everolimus in the treatment of patients with metastatic melanoma: a phase 2 trial of the Sarah Cannon Oncology Research Consortium

BACKGROUND

In this phase 2 study, the activity and tolerability of the combination of bevacizumab, an inhibitor of angiogenesis, and everolimus, an inhibitor of the mammalian target of rapamycin (mTOR), was evaluated in the treatment of patients with metastatic melanoma.

METHODS

Patients with metastatic melanoma who had received up to 2 previous systemic regimens (chemotherapy and/or immunotherapy) were eligible. Previous treatment with angiogenesis or mTOR inhibitors was not allowed. All patients received bevacizumab at a dose of 15 mg/kg intravenously every 21 days and everolimus at a dose of 10 mg orally daily. Patients were re-evaluated every 6 weeks; those with an objective response or stable disease (according to Response Evaluation Criteria in Solid Tumors [RECIST]) continued therapy until tumor progression or unacceptable toxicity occurred.

RESULTS

Fifty-seven patients with metastatic melanoma received a median of 4 treatment cycles (range, 1-14+ cycles). Seven patients (12%) achieved major responses, whereas 33 patients (58%) were found to have stable disease at the time of first evaluation. The median progression-free and overall survivals were 4 months and 8.6 months, respectively. Approximately 43% of patients were alive after 12 months of follow-up. The treatment regimen was well tolerated by the majority of patients.

CONCLUSIONS

The combination of bevacizumab and everolimus was found to have moderate activity and was well tolerated in the treatment of patients with metastatic melanoma. Further exploration of agents with these mechanisms of action is indicated, perhaps in combination with inhibitors of the mitogen-activated protein kinase (MAPK) pathway.