Introduction/Background UTOLA assessed the efficacy of Parp-inhibitor for advanced/M+ EC pts without progression after 1st line platinum CT and to analyse efficacy in some molecular subgroups.

Methodology UTOLA is a 2/1 randomized, double-blind, placebo controlled, phase IIb trial, comparing olaparib maintenance (ola, 300 mg po BID) vs placebo (pl) until progression or intolerance with stratification on P53, MMR status, and the response to the previous CT. Primary endpoint was PFS in ITT. Main secondary endpoints were PFS according to P53 status, CT response, OS, safety. A pre-specified PFS analysis was performed according to NGS-HRD status (large genomic events).

Results 147 pts were randomized (98 to Ola, 49 to pl). 82% of the pts received at least 6 cycles of CT with 46 CR, 64 PR, 34 stable and 3 NED; tumor classification was 53% P53mut (n=75), 35% NSMP, 12% MMRd, and 1 tumor POLEmut. In total, 52% (73) were HRD positive, 79% in P53mut.

Median PFS in the ITT population was 5.6 mos (90%CI 3.8–7.4) and 4.0 (3.6–7.4) in ola and pl arms respectively (HR:0.94, p=0.29). Median PFS in P53mut were 5.6 mos (3.6–8.8) vs 3.6 ms (1.8–4.9) in ola and pl arms (HR:0.75, p=0.12) whereas 6.1 mos (3.6–11) vs 7.7 mos (2.9–14.5) (HR=1.13, p=0.3) in the P53WT.

In the HRD tumors (n=73), median PFS was 5.4 mos (90%CI 3.6–9.6) vs 3.6 mos (1.8–4.9) with pl (HR:0.59) regardless of P53 status. For the 46 pts with CR to previous CT, median PFS in ola arm reached 8.8 mos versus 3.8 mos. No difference for OS was observed.

Safety profile was similar as seen in other cancers (36% vs 10% of G3/4 toxicities).

Conclusion UTOLA suggests maintenance ola could prolong PFS in P53 +/- HRD-positive advanced/M+ EC. These data should be confirmed and warrants further PARP inhibitor studies in this population.

Disclosures COI cf. attached

This study was funded by AstraZeneca.