Initiation of Rolling NDA and Interim Duration of Therapy Data

On July 23, 2024 Verastem, Inc. (the "Company" or "Verastem") reported initiating the rolling submission of a New Drug Application ("NDA") to the U.S. Food and Drug Administration ("FDA") seeking accelerated approval of the combination of avutometinib and defactinib for patients with recurrent Kirsten rat sarcoma viral oncogene homolog ("KRAS") mutant ("KRAS mt") low-grade serous ovarian cancer ("LGSOC") who received at least one prior systemic therapy (Press release, Verastem, JUL 23, 2024, View Source [SID1234645017]). The rolling review process allows Verastem to submit completed sections of an application for review by the FDA before all sections become available. The initial sections of the application will include the completed nonclinical and quality sections. The Company plans to seek the broadest label possible with mature RAMP 201 data to inform final indication. Previously, the FDA granted Orphan Drug Designation for the combination in LGSOC and Breakthrough Therapy Designation for the combination for treatment of patients with LGSOC with recurrent disease after one or more prior lines of therapy, including platinum-based chemotherapy. The Company plans to request a priority review of the NDA. Currently, there are no FDA-approved treatments specifically for recurrent LGSOC.

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The Company estimates the total annual incident addressable market opportunity for this product candidate to be approximately $300 million for KRAS mt and approximately $270 million KRAS wild-type ("KRAS wt") populations, respectively. The Company estimates the total prevalent addressable market opportunity to be approximately $1.7 billion for KRAS mt and approximately $1.1 billion for KRAS wt populations, respectively. The Company’s estimates of the patient population, pricing and revenue opportunities for its product candidates, including for KRAS mt and KRAS wt patients with LGSOC, are based on a number of internal and third-party estimates and assumptions, including, without limitation, internal forecasts, the median duration of treatment from initial interim clinical data and the assumed prices at which we can commercialize our product candidates. Specifically, the Company’s estimates of total addressable market opportunities are based on: (a) estimated annual incidence of KRAS mt and KRAS wt populations of approximately 500 and 1,000 patients, respectively, (b) estimated prevalence of KRAS mt and KRAS wt populations of approximately 2,800 and 4,200 patients, respectively, (c) the average duration of therapy as observed in Verastem clinical trials of 18 months and eight months for KRAS mt and KRAS wt populations, respectively, and (d) an estimated cost of therapy of $34,000 per month consistent with other recent oncology drug launches.

The average duration of therapy included in this calculation is based, in part, on the estimated duration of therapy for patients dosed with the combination of avutometinib and defactinib for the combined Parts A, B, and C in RAMP 201 as of the latest data cutoff in February 2024. Amongst 115 patients, 58 enrolled with KRAS mutated LGSOC and 57 had wild-type, or non-mutated, KRAS. The estimated median duration of therapy for all patients is nine months and the estimated mean duration of therapy is 14 months. For KRAS mt, the estimated median duration of therapy is 14 months and the estimated mean duration of therapy is 18 months with 31 patients still on treatment as of the data cutoff date. For KRAS wt, the estimated median duration of therapy is seven months and the estimated mean duration of therapy is 11 months with 12 patients still on treatment as of the data cutoff date.

Estimated median duration of therapy was calculated using Kaplan-Meier methods. Estimated mean duration of therapy was calculated by projecting complete time on treatment for patients still on treatment by sampling from an exponential distribution conditional on the observed duration through the cutoff date.

GenFleet Collaboration

In August 2023, the Company entered into a collaboration and option agreement (the "GenFleet Agreement") with GenFleet Therapeutics (Shanghai), Inc. ("GenFleet") pursuant to which GenFleet granted the Company options to obtain exclusive development and commercialization rights worldwide outside of mainland China, Hong Kong, Macau, and Taiwan (the "GenFleet Territory") for up to three oncology programs targeting RAS pathway driven cancers (the "GenFleet Options"). The Company may exercise its GenFleet Options on a program-by-program basis. An investigational new drug application by GenFleet in China for GFH375/VS-7375, an oral KRAS G12D (ON/OFF) inhibitor, was cleared in June 2024, following which GenFleet initiated Phase 1/2 trial in solid tumors with KRAS G12D mutation for GFH375/VS-7375 in China in June 2024. In July 2024, the Company announced that the first patient had been dosed in a Phase 1/2 trial in China, conducted by GenFleet, evaluating GFH375/VS-7375, a KRAS G12D (ON/OFF) inhibitor. The Phase 1 study is being conducted in approximately 20 hospitals in China and will evaluate the safety and efficacy of GFH375/VS-7375 in patients with advanced KRAS G12D mutant solid tumors. The Phase 1 study will determine the recommended Phase 2 dose (RP2D) and then further evaluate in Phase 2 the efficacy and safety of GFH375/VS-7375 in patients with advanced solid tumors, such as pancreatic ductal adenocarcinoma, colorectal cancer and non-small cell lung cancer.

Note Regarding Presentation of Clinical Data and Market Opportunities

Interim, initial "top-line" and preliminary data or statistical analyses and projections based thereon, may not be predictive of the results from final, more mature clinical data.

Interim, initial "top-line," and preliminary data or statistical analyses from clinical trials, including the estimated and projected duration of therapy for RAMP 201 patients based on initial topline results with a minimum of five months follow up, may change as more mature patient data becomes available, may be more or less positive than the final data, and may be subject to audit and verification procedures that could result in material changes in the mature data. Thus, such interim and projected data should be considered carefully and with caution and may not necessarily be predictive of the results from final, more mature clinical data.

The estimated mean and median duration of therapy of patients in our RAMP 201 trial are based on interim clinical data and estimates and projections extrapolated thereof. Such interim results and the estimated projections based thereon may not be reproduced in any current or potential future clinical trials, and thus should be considered carefully and with caution, and may not necessarily be predictive of the results from final, more mature clinical data. More mature data from the RAMP 201 trial may materially differ from and be less positive than the interim and initial topline data reported herein Material adverse differences in final data, compared to preliminary or interim data, could severely and adversely affect our financial results, business and business prospects, including our estimates of the addressable market opportunity.

The market opportunities for our product candidates can be smaller than we estimate or the approvals that we obtain may be based on a narrower definition of the patient population.

The potential market opportunity for The Company’s product candidates is difficult to estimate precisely. For example, the number of patients suffering from each of recurrent KRAS mutant LGSOC and KRAS wild-type LGSOC populations we are targeting is small and has not been established with precision. Due to the rarity of our target indications, there is no comprehensive patient registry or other method of establishing with precision the actual number of patients with KRAS mutant LGSOC and KRAS wild-type LGSOC. As a result, we have had to rely on other available sources to derive clinical prevalence estimates for our target indications. Management of the Company makes estimates, including those contained in this Current Report on Form 8-K, regarding the incidence and prevalence of target patient populations, the rate of recurrence and the median survival for particular diseases, including with respect to LGSOC, based on various third-party sources and internally generated analysis and use such estimates in making decisions regarding the Company’s drug development strategy determining indications on which to focus in preclinical or clinical trials.

Management’s estimates of the patient population, pricing and revenue opportunities for the Company’s product candidates, including KRAS mt and KRAS wt for patients with LGSOC, are based on a number of internal and third-party estimates, including, without limitation, internal forecasts of potential market penetration, the median duration of treatment from initial interim clinical data and the assumed prices at which we can commercialize our product candidates. These estimates may be inaccurate or based on imprecise data. For example, if approved by the FDA, the market opportunity of the Company’s product candidates will depend on, among other things, acceptance by the medical community, patient access, drug pricing and reimbursement. The number of patients in the addressable market may turn out to be lower than expected, patients may not be otherwise amenable to treatment with the Company’s drugs, or new patients may become increasingly difficult to identify or gain access to, all of which may significantly harm the Company’s business, financial condition, results of operations, and prospects. Further, if any approval that the Company obtains is based on a narrower definition of patient populations than the Company had anticipated, the potential market for the Company’s product candidates will be smaller than management’s current estimates. A smaller patient population in our target indications would have a materially adverse effect on the Company’s ability to achieve commercialization and generate revenues.