Societal Versus Healthcare Perspectives on the Cost Effectiveness of Ocrelizumab for Treatment of Primary Progressive Multiple Sclerosis in Aotearoa New Zealand.

OBJECTIVES

Multiple sclerosis (MS) is a progressive, degenerative, autoimmune neuronal disease. This study compares the impact of a societal versus a healthcare perspective on the cost effectiveness of treatment of primary progressive MS (PPMS) with ocrelizumab (OCR) versus best supportive care (BSC) in New Zealand.

METHODS

The analysis utilises a lifetime cohort Markov model based on ten Expanded Disability Status Scale (EDSS) states, plus death. It has two structurally identical arms, with forward transition probabilities in the treatment arm obtained by multiplying forward transition probabilities (converted to rates, and back to probabilities) in the control arm by the 12-week disability progression hazard ratio in the clinical trial ORATORIO. Direct and indirect costs of MS were estimated from a 2017 Australian survey and converted to 2024 NZ dollars using purchasing power parity and the NZ consumer price index. Future costs and benefits were discounted at 3.5% per annum. The model is calibrated to NZ mortality for PPMS, and therapy ends when wheelchair dependence (EDSS7) is reached.

RESULTS

For a modelled cohort 40 years of age starting at the ORATORIO distribution of EDSS, at 50% of the list price (viz. 50% rebate on $NZ37,384 per patient per annum), the incremental cost-effectiveness ratio (ICER) of OCR versus BSC is $NZ114,427 per QALY ($US64,651) from a societal perspective or $NZ146,711 ($US82,892) from a healthcare perspective. From a societal perspective, at Treasury's willingness to pay (WTP) criterion of $NZ120,200, an acquisition cost up to 56% of list price ($NZ20,935; 44% rebate) is justifiable. From a healthcare payer perspective, at Treasury's implied WTP of $NZ43,313, an acquisition cost up to 10% of list price ($NZ3738; 90% rebate) is justifiable. Based on this metric, a 5.6-fold higher investment in OCR can be justified from a societal perspective compared with a healthcare perspective. Alternatively, an acquisition cost up to 37.9% of list price (viz. 62.1% rebate or $NZ14,169) could be justified if the criterion of one GDP per capita ($NZ83,011) is used as a societal funding threshold. These results are sensitive to the cost of BSC from a societal perspective but not from a healthcare perspective. From both perspectives the cost effectiveness is sensitive to the acquisition cost and efficacy of OCR, potential waning of efficacy, the age and EDSS state when therapy begins, the cost and timing of entry of a biosimilar pharmaceutical and the discount rate.

CONCLUSIONS

Treatment of PPMS with OCR is more cost effective from a societal than a healthcare perspective, therefore prioritisation of public funding of novel pharmaceuticals for MS and other resource intensive chronic health conditions will depend critically upon the study perspective.