Kazia prunes failed brain cancer trial data set to manufacture path to FDA

Kazia Therapeutics has found a way to try to salvage a win from a failed late-phase brain cancer trial. By removing part of the control arm, the biotech has emerged with survival data it will share with the FDA to see whether a path to accelerated approval has opened up. 

The data come from a platform study sponsored by the Global Coalition for Adaptive Research. The trial has enrolled patients with newly diagnosed and recurrent glioblastoma, a hard-to-treat brain cancer, to receive molecules developed by companies including Bayer and Biohaven. The design allows researchers to compare a revolving cast of candidates to a standard-of-care control arm in a single study.

In August 2022, Kazia said its contribution to the study, a PI3K/mTOR inhibitor discovered by Genentech, failed to meet the threshold for advancing to the next stage of the trial. Now, Kazia has shared the data behind the failure—and made the case that there is a positive story to tell. 

Investigators enrolled two subgroups of patients to receive Kazia’s candidate paxalisib. The molecule was numerically worse than the control treatment, lomustine, in patients with recurrent disease, achieving a median overall survival (OS) of 8.05 months compared to 9.69 months for the standard of care. That part of the study featured 213 patients, split roughly evenly between paxalisib and the control.

Kazia focused its discussion of the data on the other subgroup, which enrolled newly diagnosed patients with a form of the disease that is less likely to respond to the chemotherapy drug temozolomide. In that subgroup, Kazia reported a median OS of 14.77 months in 54 recipients of paxalisib.

The result was barely better than the 13.84 months seen in the temozolomide control cohort. However, Kazia found a subset of the control arm that painted a better picture of paxalisib. Because paxalisib was added to the platform trial around 18 months after the study began, roughly one-third of the 75 patients in the newly diagnosed control arm were enrolled before dosing of Kazia’s drug candidate started.

Limiting the control arm to the 46 patients who were enrolled concurrently to Kazia’s prospect resulted in a median OS of 11.89 months. Kazia CEO John Friend, M.D., hailed the result as a “3.8 month improvement in overall survival, an approximate 33% improvement,” in a statement.

The biotech now plans to discuss the data with the FDA to “determine if a potential path to accelerated approval is appropriate for paxalisib.” Kazia’s share price rose around 70% in premarket trading, but that jump only brought it up to 33 cents.