SOLO1 versus SOLO2: Cost-effectiveness of olaparib as maintenance therapy for newly diagnosed and platinum-sensitive recurrent ovarian carcinoma among women with germline BRCA mutations (gBRCAmut).

Abstract

5545 Background: With the December 19, 2018 regulatory approval by the US FDA of olaparib tablets as maintenance therapy for women with deleterious or suspected deleterious germline or somatic BRCAmut advanced ovarian carcinoma, it becomes important to clarify the role of PARP inhibitors in this disease. We evaluated cost-effectiveness of olaparib in the upfront (SOLO1) versus the recurrent maintenance setting (SOLO2). Methods: Data were obtained from SOLO1, the phase 3 placebo-controlled randomized upfront maintenance study among gBRCAmut patients [median PFS greater than 49.8 vs 13.8m: HR 0.30; 95% CI, 0.23-0.41; p < 0.001, NCT01844986] and SOLO2, the phase 3 placebo-controlled randomized maintenance study among gBRCAmut patients with platinum-sensitive recurrence and at least two prior lines of therapy [median PFS 19.1 vs 5.5m: HR 0.30; 95% CI, 0.22-0.41; p < 0.0001, NCT01874353]. Investigator-assessed median PFS and toxicity data from the trials were incorporated in a Markov model which transitioned patients through response, hematologic complications, non-hematologic complications, progression, and death. Using TreeAge Pro 2015, the costs of pre-treatment testing (eg. gBRCAmut), medications, and management of adverse effects were analyzed. Incremental cost-effectiveness ratios (ICERs) per month of life gained and individual PFS-life year saved (PFS-LYS) were also calculated and compared. Results: In SOLO1, cost prior to progression was 1.7x that of SOLO2 ($937,440 vs $564,451). With the extended, estimated median PFS of at least 49.8m for SOLO1 and 19.1m for SOLO2, upfront maintenance therapy was more cost-effective. SOLO 1 was associated with $312,480 PF-LYS per individual patient, while SOLO2 demonstrated $498,045 PF-LYS. Maintenance olaparib was found to be more cost-effective in the 1st-line setting, with an ICER of $12,149 per month of life gained when compared directly to SOLO2. Conclusions: Although the higher cost associated with olaparib in SOLO1 reflects the longer time patients stay on drug due to extended PFS, the ICER supports early use in the disease course as first-line maintenance therapy among women with gBRCAmut advanced ovarian carcinoma.