OBJECTIVES:

Orphan products are associated with increased evidence uncertainty for HTA decision-making. Therefore, HTA agencies have adopted orphan-specific pathways or considerations. However, as usually there is no appropriate comparator, forecasting price of novel orphan products with existing methods is challenging. This research aimed to determine accuracy of using a value-price model to forecast price of an orphan product across different payer archetypes.

METHODS:

To forecast the price of burosumab (X-linked hypophosphatemia treatment) in England, France, and Germany, 8 analogues assessed since 2015 with various indications, launch sequencing, and cost were selected. A MCDA model with key attributes reflecting payer drivers for orphan products was developed. Value scores were derived for each product using HTA and regulatory documents. Annual cost of analogues was calculated from launch price. Analogue value score and price were plotted on a linear regression, used to forecast burosumab price in each market and compared to actual prices.

RESULTS:

Different payer value drivers produced variable value scores. Prevalence and clinical benefit drivers in Germany provided the largest value score and range (8%–94%; range=86%). Smaller value score ranges were attributed to HTA pathway and economic drivers in England (29%–79%; range=50%) and innovation in France (21%–88%; range=67%).

There was a positive value-price relationship across markets. France had the strongest correlation (R²=0.94) and greatest accuracy of burosumab forecast price versus actual price at -3% ($227,066 versus $220,155). Despite lower R², there was high accuracy to actual price of -4% in England ($274,167 versus $264,027; R²=0.67) and 5% in Germany ($208,574 versus $220,155; R²=0.66).

CONCLUSIONS:

Analyses suggested that a value-price relationship can accurately forecast price, regardless of payer archetype. However, correlation strength and accuracy may be unrelated. Exclusion of pricing drivers, e.g., reference pricing and England net prices, are limitations. Further research with additional analogues, markets and sensitivity analysis is required.