BioXcel Therapeutics Reports Positive Overall Survival Results from Single-Arm, Open-Label Phase 2 Trial of BXCL701 in Patients with Small Cell Neuroendocrine Prostate Cancer

  • Median overall survival of 13.6 months with BXCL701 + KEYTRUDA® (pembrolizumab), compared to 7.6 months with checkpoint inhibitor monotherapy (CPI) in late-line refractory patients in separate, Phase 2 trial1
  • 56% of studied patients alive at one year following treatment with BXCL701 + KEYTRUDA®, compared to ~33% with checkpoint inhibitor monotherapy (CPI) in late-line refractory patients in separate, Phase 2 trial1
  • Results support potential development in small cell lung cancer (SCLC) and other neuroendocrine tumors

Reno, Nevada (UroToday.com) -- BioXcel Therapeutics, Inc. (Nasdaq: BTAI), a biopharmaceutical company utilizing artificial intelligence to develop transformative medicines in neuroscience and immuno-oncology, announced positive overall survival (OS) data from its Phase 2 trial of BXCL701, the Company's investigational oral innate immune activator, in combination with KEYTRUDA® (pembrolizumab) in patients with small cell neuroendocrine prostate cancer (SCNC). As of a data cutoff of September 6, 2023, evaluable patients with SCNC (n=28) showed a median OS of 13.6 months (95% CI 10.9–NR), and a 12-month survival rate of 56.5%.

“OS is the most meaningful measure by which the effectiveness of an oncology treatment is evaluated. Though these results are based on a non-randomized cohort of patients, observing a median OS of this duration including patients with long-term survival at 12 months and beyond shows exceptional promise, bearing in mind historic data with checkpoint inhibitor monotherapy in this high-risk subset of prostate cancer,” said Rahul Aggarwal, M.D., Principal Investigator, Associate Director for Clinical Sciences, Helen Diller Family Comprehensive Cancer Center, and Professor of Medicine at the University of California San Francisco (UCSF). “SCNC represents a major unmet medical need, with the majority of patients unfortunately succumbing to their disease in less than one year following chemotherapy. The results of this trial suggest that BXCL701 has the potential to extend the lives of patients, and I look forward to its continued clinical development.”
SCNC, classified as a “cold” tumor, represents an underserved, growing patient population, with cases increasing due to earlier and more widespread use of androgen receptor inhibitors. In 2023, there will be an estimated 288,3002 new patients with prostate cancer in the United States, with approximately 11,532 patients progressing to SCNC.

“We believe our trial results are highly encouraging for patients with this disease and have potential implications for our evaluation of BXCL701 for the treatment of other high-grade neuroendocrine tumors, such as small cell lung cancer, where effective therapies are lacking,” said Vincent J. O’Neill, M.D., Chief R&D Officer, OnkosXcel Therapeutics, a wholly owned subsidiary of BioXcel Therapeutics. “We intend to discuss these data with the FDA to help determine our next steps with clinical development.”

The Phase 2 trial is an open-label, multicenter study to evaluate the safety and efficacy of BXCL701 in combination with pembrolizumab in men with SCNC. Twenty-eight (28) evaluable SCNC patients received 0.3 mg of BXCL701 twice daily (BID) on days 1 through 14 of a 21-day cycle (0.2 mg BID the first week of cycle 1) plus 200 mg of pembrolizumab administered intravenously on day 1 and every subsequent 21 days. The primary objective of the trial is a composite response rate defined as either objective response by RECIST 1.1 criteria and/or PSA50 and/or CTC count conversion.

Secondary objectives include duration of response, progression-free survival, overall survival, and biomarker evaluation as measured by changes in circulating cytokines and correlation of outcome with baseline tumor characteristics.

The Company is continuing to actively evaluate strategic options for OnkosXcel Therapeutics, including potential financing, strategic partnership, or M&A.

Source: BioXcel Therapeutics. (2023). BioXcel Therapeutics Reports Positive Overall Survival Results from Single-Arm, Open-Label Phase 2 Trial of BXCL701 in Patients with Small Cell Neuroendocrine Prostate Cancer [Press release]. https://ir.bioxceltherapeutics.com/news-releases/news-release-details/bioxcel-therapeutics-reports-positive-overall-survival-results.

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ASCO GU 2023: First-in-Class Oral Innate Immune Activator BXCL701 Combined with Pembrolizumab in Patients with Metastatic, Castration-Resistant Prostate Cancer (mCRPC) of Small Cell Neuroendocrine (SCNC) Phenotype: Phase 2a Final Results

ASCO GU 2022: BXCL701: First-in-Class Oral Activator of Systemic Innate Immunity Combined With Pembrolizumab, in Patients With mCRPC of Adenocarcinoma Phenotype—Phase 2a Results