517O Overall survival (OS) at 7-year (y) follow-up (f/u) in patients (pts) with newly diagnosed advanced ovarian cancer (OC) and a BRCA mutation (BRCAm) who received maintenance olaparib in the SOLO1/GOG-3004 trial

Abstract

In the Phase III SOLO1/GOG-3004 trial (NCT01844986), maintenance olaparib provided sustained benefit beyond the end of treatment in pts with newly diagnosed advanced OC and a BRCAm. At 5-y f/u, median progression-free survival was 56.0 months [m] with olaparib vs 13.8m with placebo (pbo) (HR 0.33; 95% CI 0.25–0.43); 48% vs 21% of pts, respectively, were progression-free (KM estimates) (Banerjee et al. Lancet Oncol 2021). Given that most OC deaths occur 5‒10y after diagnosis, we report OS in SOLO1 at 7-y f/u, a clinically relevant timepoint. Pts who were in response to first-line platinum-based chemotherapy received maintenance olaparib tablets 300 mg bid or pbo for up to 2y or until progression. A descriptive analysis of OS, a secondary endpoint, was performed 7y after the last pt was randomized; prespecified final analysis of OS is planned at 60% data maturity. 260 pts were randomized to olaparib and 131 to pbo (median treatment duration 24.6 vs 13.9m, respectively). At OS data maturity of 38.1% (data cut-off 7 Mar 2022), median OS was not reached in olaparib pts vs 75.2m in pbo pts, with an OS HR of 0.55 (95% CI 0.40–0.76; unadjusted for crossover; 44.3% of pbo pts received a PARP inhibitor in a subsequent line of therapy) (Table). At 7y, 45.3% of olaparib pts vs 20.6% of pbo pts were alive and had still not received a first subsequent treatment (KM estimates). The incidence of MDS/AML remained low and new primary malignancies remained balanced between arms (Table).Table: 517OOlaparibPboOSN=260N=131Median f/u, m88.987.4Events, n (%)84 (32.3)65 (49.6)Median OS, mNR75.2HR (95% CI)0.55 (0.40–0.76)P value0.0004*7-y OS rate,† %67.046.5AEs of special interest, n (%)N=260N=130‡MDS/AML4 (1.5)1 (0.8)New primary malignancies14 (5.4)8 (6.2)Pneumonitis5 (1.9)0*P<0.0001 required for statistical significance; †KM estimates; ‡1 pt randomized to pbo did not receive treatment. AE, adverse event; AML, acute myeloid leukaemia; CI, confidence interval; HR, hazard ratio; KM, Kaplan–Meier; MDS, myelodysplastic syndrome; NR, not reached. Open table in a new tab *P<0.0001 required for statistical significance; †KM estimates; ‡1 pt randomized to pbo did not receive treatment. AE, adverse event; AML, acute myeloid leukaemia; CI, confidence interval; HR, hazard ratio; KM, Kaplan–Meier; MDS, myelodysplastic syndrome; NR, not reached. 2y of maintenance olaparib provided a clinically meaningful improvement in OS over pbo in pts with newly diagnosed advanced OC and a BRCAm. At 7y, 67.0% of olaparib pts vs 46.5% of pbo pts were alive; no new safety signals were detected. These data provide the longest f/u for any PARP inhibitor in this setting and support use of maintenance olaparib to achieve long-term remission and enhance the potential for cure.