OBJECTIVES: The MONALEESA-7 trial demonstrated the efficacy and safety of ribociclib plus NSAI (R+NSAI) vs. placebo plus NSAI for pre-/peri-menopausal women with HR+/HER2- ABC who had received no prior endocrine therapy (ET) for advanced disease. This analysis evaluated the cost-effectiveness of R+NSAI vs. NSAI in this population from a Canadian healthcare payer perspective.

METHODS: The incremental cost-effectiveness ratio (ICER) expressed as incremental costs per quality-adjusted life-year (QALY) gained for R+NSAI versus NSAI, was estimated using a semi-Markov cohort model developed in Microsoft Excel with states for progression-free (PF), post-progression (PP), and dead. A 15-year time horizon was used. Survival distributions for PFS, PPS and time to discontinuation (TTD) were based on parametric survival distribution fit to data from MONALEESA-7. Health-state utilities were estimated using EQ-5D index values collected in MONALEESA-7. Direct costs of ABC treatment (medication and administration costs, follow-up and monitoring, adverse events, subsequent treatments) were based on Canadian specific values from published sources. Costs ($ CAN) and QALYs were discounted at 1.5% annually.

RESULTS: In the base case, R+NSAI was estimated to result in gains of 1.44 life years and 1.19 QALYs vs. NSAI, at an incremental cost of $210,767. The ICER of R+NSAI vs. NSAI was $177,245 per QALY gained based on deterministic analyses and $178,872 based on the mean of probabilistic analyses. Results were sensitive to parametric distributions used for projecting long-term TTD, PFS, and PPS.

CONCLUSIONS: For pre-/peri-menopausal women with HR+/HER2- ABC who had received no prior ET for advanced disease, R+NSAI is projected to result in substantial gains in QALYs compared with NSAI. At its current list price, ribociclib used in combination with an NSAI is cost-effective in this population at an ICER threshold of approximately $177,245. These results may be useful in deliberations regarding reimbursement and access to this treatment.