Zentalis reports median survival of 15.8 months in ovarian cancer trial group

Key Facts

Zentalis Pharmaceuticals said on 18 October 2026 that median overall survival reached 15.8 months among patients positive for the Cyclin E1 biomarker in a trial of azenosertib for ovarian cancer. This group included 48 patients in the interim analysis of Part One B of the DENALI study, according to the company's statement. Median overall survival was 7.5 months in the biomarker-negative group, which included 46 patients. Overall survival follow-up was a secondary objective of the study, with a data cutoff of 2 September 2025. The comparison reflects differences in outcomes between two groups based on biomarker status and does not establish the drug's superiority over standard treatment in a randomized controlled comparison.

Part One B of DENALI included a total of 102 patients, according to Zentalis' disclosure, representing the full population enrolled in this part. The study's primary endpoint was the objective response rate, while the survival analysis forms part of treatment outcome follow-up. The company determined biomarker status retrospectively, using immunohistochemistry and its own cutoff to classify patients. In earlier results for biomarker-positive patients, the response rate among those evaluable for response was 34.9%, according to a report published by Investing.com. Median duration of response for this group was 6.3 months, according to the report on the interim survival results.

Zentalis estimates that about 50% of patients with platinum-resistant ovarian cancer are positive for the Cyclin E1 biomarker, the population targeted by the azenosertib development program. The drug works by inhibiting the WEE1 enzyme, allowing the cell cycle to continue despite DNA damage, according to the company's explanation. This process leads to the accumulation of damage and cancer cell death, according to its description of the treatment's mechanism of action. The company selected a dose of 400 mg once daily for pivotal studies, on a schedule of 5 days on treatment and 2 days off. In its dose-selection announcement, it said no "treatment-related deaths" were recorded in the interim analysis that informed the decision.

On the regulatory front, azenosertib received Fast Track designation from the U.S. Food and Drug Administration for biomarker-positive platinum-resistant ovarian cancer, according to Zentalis. The company said the agency acknowledged that the DENALI study population could support an accelerated approval pathway, subject to the strength of the data and the therapies approved at the time of the regulatory decision. In parallel, the confirmatory ASPENOVA study was designed as a randomized controlled Phase Three trial, according to the company's clinical progress update. The study aims to enroll about 420 patients to compare azenosertib with investigator-selected single-agent chemotherapy. Zentalis announced in May 2026 that the first patient had been dosed in the trial.

Among analysts, H.C. Wainwright maintained its Buy recommendation on Zentalis shares following the interim survival results, according to an Investing.com report published on the day of the news. The firm kept its price target at $10.00 per share. The stock had previously risen 4.4% before the market opened on 5 October 2026, after Leerink Partners initiated coverage with an Outperform rating, according to a separate report by the website. On its financial position, Zentalis reported cash, cash equivalents and marketable securities of $174.6 million at the end of June 2026. That compares with a balance of $245.9 million at the end of December 2025, according to its financial results update.

Zentalis scheduled an oral presentation of the survival results for 23 October 2026 at the European Society for Medical Oncology congress. The next milestone for the DENALI program is topline results from Part Two, which the company expects to report in the first half of 2027. The company had announced in its quarterly update that enrollment in Parts Two A and Two B was complete. It said the timing of the results announcement allows the data to mature after enrollment is completed. The potential accelerated approval pathway depends on results from this part and regulatory review, including an assessment of the strength of the evidence and available treatments at the time of the decision.