Preclinical Signals of Ubamatamab Show Promise in Recurrent Ovarian Cancer Cells

David O'Malley, MD, a professor in the Department of Obstetrics and Gynecology at The Ohio State University College of Medicine and the director of the Division of Gynecologic Oncology at the OSUCCC–James, discusses the preclinical signals of the novel agent ubamatamab.

The MUC16 antibody has shown evidence of durable responses for patients with recurrent ovarian cancer based off the phase 1, first-in-human study of ubamatamab, REGN4018 (NCT03564340). The study enrolled 78 patients who had a median number of 4.5 prior therapies at a median duration of exposure at 12 weeks. The findings showed that objective responses were observed in patients given 20-800 mg doses of the MUC16 targeting therapy and there was an overall response rate of 14.3% (95% CI, 5.4-28.5). The median duration of response was 12.2 months with a disease control rate of 57.1% (95% CI, 41-72.3).

The novel agent was also determined to be tolerable thus far, with the most common treatment-emergent adverse events (TEAEs) being cytokine release syndrome (73.1%), all of which were either grade 1 or 2, and pain (87.2%) that primarily occurred in weeks 1 or 2 of treatment. The most common grade 3 or higher TEAEs were anemia (23.1%) and abdominal pain (19.2%).

O’Malley discusses these results and the findings of an exploratory analysis of patients who had 75% of tumor cells with 2+ baseline MUC16 immunohistochemical (IHC) staining as well as his excitement for the future of ubamatamab as a phase 2 expansion of the study has been initiated.

Transcript:

0:08 | We presented an efficacy population of those patients who received at least 1 dose at 20 mg or more, which was 42 patients. What we saw was overall response rates of 14%. We [also] looked at an exploratory group of patients that had high MUC16 expression. In the efficacy cohort, there was 13 patients that had that high expression, defined as greater than 75% of tumor cells expressing 2-plus MUC16 IHC, [and] we found a 31% response rate in those 13 patients. Obviously, that's an exploratory analysis, but though that biomarker continues to be developed, it is an exciting option moving forward with ubamatamab.