PARP Inhibition May Have a Role in HRR-mutant Urothelial Carcinoma

By Leah Lawrence - July 20, 2022

Results from the phase-2 BAYOU study indicated that the addition of the PARP inhibitor olaparib to durvalumab did not improve survival outcomes in an unselected group of patients with metastatic urothelial carcinoma.

The trial randomly assigned 154 patients 1:1 to durvalumab plus olaparib or durvalumab plus placebo. In the intention-to-treat population, the median progression-free survival (PFS) was 4.2 months for durvalumab plus olaparib compared with 3.5 months with durvalumab alone.

Overall survival was also similar for the combination compared with monotherapy (10.2 vs. 10.7 months).

“The study did not meet its primary end point as there was no progression-free survival benefit with durvalumab plus olaparib versus durvalumab plus placebo in a biomarker-unselected population,” the researchers wrote in The Journal of Clinical Oncology.

However, the researchers also looked at the 20% of patients with mutant HRR status (HRRm).

“Although limited by small numbers, secondary analyses involving patients with HRRm showed a nearly 4-month increase in median PFS with durvalumab plus olaparib versus durvalumab alone,” the researchers wrote.

The median PFS for durvalumab plus olaparib was 5.6 months compared with 1.8 months for durvalumab alone (hazard ratio=0.18; 95% CI, 0.06-0.47). According to the researchers, this suggests a potential role for PARP inhibition in patients with urothelial carcinoma harboring HRRm.

No new safety signals were observed with the combination compared with durvalumab alone.