Patterns of progression and subsequent management of patients with BRCA1/2 mutated platinum-sensitive recurrent epithelial ovarian cancer (EOC) progressing on olaparib versus placebo: the SOLO2/ENGOT Ov-21 trial (NCT01874353).

Abstract

6070 Background: Olaparib maintenance is a standard treatment of BRCA1/2 mutated platinum-sensitive recurrent EOC. Despite improvement in PFS, olaparib (O) resistance often occurs and the optimal management of post-olaparib progression remains undefined. Methods: Data of patients who participated in the SOLO-2 trial and progressed were analyzed. Primary objective was to depict the patterns of progression of patients treated with O compared to placebo (P). Secondary objectives include description of post-progression treatments. Results: 106/195 (54%) and 80/99 (81%) patients had a RECIST progression in the O and P arms respectively. As permitted in the protocol, 37 (35%) pts continued O despite a RECIST progression and 10 remained on treatment at the date of data base cut-off of the primary endpoint. Median duration of O post progression was 3.2 months (range: 1 to 19.4). In the placebo arm, only 20% of the patients with progressive disease continued placebo during a median of 1.6 months (range:1.1 to 16.1). Patterns of sites of progressive disease were similar in the O and P arms respectively in terms of liver (21% vs 18%), lung (4% vs 3%), lymph node (20% vs 16%) peritoneal (48% vs 32%) or brain metastases (0% vs 2%). Number of sites of relapsing disease were similar in the O and P arm respectively (1 (68% vs 64), ≥2 (32% vs 36%). A total of 54 (51%) patients in the O arm and 42 (53%) in the P arm received subsequent platinum-based therapy. In both arms, 8% received bevacizumab and 6% received no further treatment. Median PFS with first post-study platinum-based and non platinum-based therapy were 7.1 months and 5.6 months respectively. In the P arm, 18 (23) patients received PARP inhibitors following the first subsequent chemotherapy. Conclusions: Patterns of disease progression and subsequent chemotherapy were similar in patients receiving O or P in the SOLO2 trial. Instead of switching to chemotherapy, continuing O at the time of RECIST progression was an option for 35% of the patients. Clinical trial information: NCT01874353.