Boston-based biopharmaceutical company Verastem Oncology (NASDAQ: VSTM) announced preliminary data from its investigator-initiated study of the combination of RAF/MEK and FAK in KRAS mutant tumors. The company, which develops and commercializes new medicines for patients battling cancer, presented the information at the 2020 American Association for Cancer Research (AACR) virtual annual meeting.
The combination of VS-6766 and defactinib demonstrated a 67% overall response rate in KRAS mutant low-grade serous ovarian cancer. VS-6766 is Verastem’s RAF/MEK inhibitor while defactnib is its FAK inhibitor.
A subsequent combined analysis involving the combination of the VS-6766 monotherapy and defactnib demonstrated a 57% overall response rate in KRASG12V non-small cell lung cancer.
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Encouraging early response rates
Verastem’s phase 1 trial is an open label, dose escalation and expansion study that is ongoing in patients with advanced solid tumors including low-grade serous ovarian cancer (LGSOC), KRAS mutant non-small cell lung cancer (NSCLC), and KRAS mutant colorectal cancer. In the LGSOC cohort, four out of six patients responded and the median time on the treatment was 20.5 months. The KRAS mutant NSCLC cohort included ten patients of which eight achieved disease control and one achieved a partial response.
The company also conducted a combined analysis based on the observation of higher response rates in patients with KRASG12V mutations. This included data from the combination study and a prior single-agent study that used a twice-weekly dosing schedule of VS-67661 to obtain a more comprehensive view of KRASG12V mutation activity. In this analysis four out of seven NSCLC patients and three out of five gynecologic cancer patients responded favorably.
Verastem CEO Brian Stuglik stated, “We are encouraged by these early response rates in KRAS mutant LGSOC and in KRAS G12V mutant tumors as they underscore the significant potential of this novel approach in areas of high unmet medical need.”
Separately, Verastem announced that net product revenue for its first quarter of 2020 is expected to be $5.0 million. On April 1st, the company affirmed its full year net product revenue guidance of $12 million to $16 million.
Management also noted that it plans to begin discussions with regulatory authorities as soon as possible to define a path for the potential combination of VS-6766 and defactnib. The company’s goal is to start a registration-directed clinical trial later this year. Meanwhile, the current study is continuing to enroll more patients into the ovarian, lung, and colorectal expansion cohorts.
Despite the rather promising clinical activity, the stock market reacted negatively to the news. Investors were unimpressed with the trial results and were apparently looking for more compelling data. A week ago, traders optimistically bid the stock up after the company announced plans for a conference call to discuss the results of the independent study.
Shares of Verastem were down nearly 50% in late afternoon trading on April 27th. Verastem must now attempt to win back investors on the merits of its latest ovarian cancer treatment and other pipeline drugs. The company is scheduled to report first quarter performance on May 14th.