Exelixis, announced positive top-line results from a randomised phase 2 trial of cabozantinib and erlotinib alone or in combination as second- or third-line therapy in patients with stage IV EGFR wild-type non-small cell lung cancer (NSCLC). This trial (Study E1512) is sponsored by the US National Cancer Institute (NCI) through a Cooperative Research and Development Agreement between the Cancer Therapy Evaluation Programme (CTEP), Division of Cancer Treatment and Diagnosis, NCI and Exelixis. Study E1512 was designed and is being conducted by the ECOG-ACRIN Cancer Research Group as part of Exelixis’ collaboration with the NCI. Joel Neal, M.D., Ph.D., from ECOG-ACRIN member institution Stanford University/Stanford Cancer Institute, chairs the study.

In the E1512 trial, 125 patients were randomized to one of the three arms: erlotinib, cabozantinib, or the combination. During a pre-planned interim ECOG-ACRIN Data Safety Monitoring Committee analysis for futility, it was found that the trial met its primary endpoint of improving progression-free survival (PFS) with cabozantinib alone and also with the combination of cabozantinib plus erlotinib, as compared to erlotinib alone, and the results were highly statistically significant. Safety data were consistent with those observed in other trials of cabozantinib. At time of analysis, the median follow-up was 5.9 months and overall survival data were immature.

The results of the trial are the subject of ongoing analyses and will be submitted by the investigators for presentation at a future medical conference.

Exelixis president and chief executive officer, Michael M. Morrissey, Ph.D., commented on the results: “This is one of the first substantial data sets from our collaboration with NCI-CTEP, which has enabled us to broaden the cabozantinib development program while focusing our internal resources on our pivotal trials. We are excited by these positive results and are looking forward to working with the trial investigators to support future development of cabozantinib in NSCLC and beyond, while we await top-line results from our pivotal phase 3 trial METEOR in metastatic renal cell carcinoma, now anticipated in the second quarter of 2015.”

Study E1512 is a randomized phase 2 trial designed to enroll 117 patients with stage IV EGFR wild-type NSCLC who had received at least one prior chemotherapy. Patients were randomised (1:1:1) to receive erlotinib (150 mg daily), cabozantinib (60 mg daily), or erlotinib plus cabozantinib (150 mg plus 40 mg daily). The primary objective of the trial is to determine whether single agent cabozantinib or combination therapy including cabozantinib extends PFS when compared to single agent erlotinib for this patient population. Secondary objectives include estimation of overall survival, best objective response, and toxicity.

After adjusting for an ineligibility rate of 10 per cent, the total required sample size for randomisation was 117 patients. Using an overall one-sided 0.10 level log rank test for each comparison, this study has 91 per cent power to detect a 50 per cent reduction in the PFS hazard rate of 0.288 to 0.144 based on the estimated accrual and follow-up period. Assuming exponential survival, this corresponds to a 100 per cent improvement in the median PFS of 2.4 months on erlotinib alone to 4.8 months on cabozantinib alone or on erlotinib plus cabozantinib. The number of PFS events needed to achieve this power for each comparison is 58 events under the alternative hypothesis.

Cabozantinib inhibits the activity of tyrosine kinases including MET, VEGFRs and RET. These receptor tyrosine kinases are involved in both normal cellular function and in pathologic processes such as oncogenesis, metastasis, tumor angiogenesis, and maintenance of the tumor microenvironment.

Cometriq (cabozantinib) is currently approved by the US Food and Drug Administration for the treatment of progressive, metastatic medullary thyroid cancer (MTC).

The European Commission granted Cometriq conditional approval for the treatment of adult patients with progressive, unresectable locally advanced or metastatic MTC. Similar to another drug approved in this setting, the approved indication states that for patients in whom Rearranged during Transfection (RET) mutation status is not known or is negative, a possible lower benefit should be taken into account before individual treatment decisions.