416P - Cost-effectiveness of first-line (1L) ribociclib use vs palbociclib in the treatment of postmenopausal women with HR+/HER2− advanced breast cancer (ABC): Analysis based on final overall survival (OS) results of MONALEESA-2 (ML-2) and PALOMA-2 (PAL-2)

Background

To evaluate cost-effectiveness of ribociclib vs palbociclib, using final ML-2 and PAL-2 OS data, in 1L treatment of postmenopausal women with HR+/HER2− ABC from Canadian payer perspective.

Methods

Partitioned survival model was developed considering 3 states (progression-free survival, progressive disease, and death) with a 1-month cycle length. Hazard ratios (HRs) for PFS and OS for ribociclib vs palbociclib (with letrozole) were derived using an anchored matching-adjusted indirect comparison (MAIC) to adjust for differences in baseline characteristics between ML-2 and PAL-2. Cost inputs included drug acquisition, healthcare resource, subsequent therapies, and adverse event costs. Trial data and published literature were used to derive utility values. Costs and effects were discounted at 1.5% per year over a lifetime horizon.

Results

Total cost of treatment with ribociclib and palbociclib were $250,004 and $254,052, respectively. For treatment with ribociclib vs palbociclib, quality-adjusted life years (QALYs) were 4.948 vs 3.981, respectively. Ribociclib was the dominant treatment as it was both cost-saving (-$4,048) and more effective (+0.968 QALYs) than palbociclib. Drug cost with ribociclib was found to be $31,819 lower than palbociclib. Probability of ribociclib being cost-effective at $50,000 per QALY was 100%. Ribociclib remained cost-effective when HRs, utilities, ribociclib drug cost, and health state costs were varied.

Conclusions

Post MAIC, significantly longer OS benefit was observed with ribociclib vs palbociclib. Ribociclib remained dominant 1L treatment option over palbociclib. Hence, ribociclib should be the preferred CDK4/6 inhibitor based on the clinical and the economic benefit.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Novartis Pharmaceuticals.

Funding

Novartis Pharmaceutical.

Disclosure

D. Soliman, K. El Ouagari, C. Biswas, M. Kalra, V. Sharma: Financial Interests, Personal, Full or part-time Employment: Novartis. All other authors have declared no conflicts of interest.