Using Value-of-Information Methods when the Disease Is Rare and the Treatment Is Expensive-The Example of Hemophilia A.

Journal of General Internal Medicine

PubMedID: 25029970

Abrahamyan L, Willan AR, Beyene J, McLimont M, Blanchette V, Feldman BM, for the Canadian Hemophilia Primary Prophylaxis (CHPS) Study Group. Using Value-of-Information Methods when the Disease Is Rare and the Treatment Is Expensive-The Example of Hemophilia A. J Gen Intern Med. 2014;29 Suppl 3S767-73.
BACKGROUND
Hemophilia A is a rare, sex-linked genetic disorder treated with intravenous administration of factor VIII (FVIII) to prevent bleeding; however, approaches vary across and within countries. Value-of-information (VOI) methods identify situations in which the cost-benefit evidence is sufficient to adopt one treatment strategy over another; when the evidence is insufficient, VOI methods provide the optimal sample size for additional research.

OBJECTIVE
The objective of the study was to use VOI methods in a cost-benefit decision context to evaluate the current evidence in support of using (1) alternate day prophylaxis (AP), (2) tailored prophylaxis (TP) or (3) on-demand treatment (OD) with FVIII to prevent arthropathy in children with severe hemophilia A.

METHODS
To apply VOI methods, several parameters such as incidence, time horizon for the decision, costs, and threshold values to avoid MRI-detected joint damage or arthropathy were defined. Two baseline threshold values of willingness to pay for avoiding arthropathy-$200,000 and $400,000-were selected for comparing the treatment strategies.

RESULTS
For threshold values??$400,0,00 prophylaxis strategies had higher expected net benefit; however, a new trial with 38 patients per arm was needed to compare AP and TP, yielding an expected net gain of over $17 million. In sensitivity analyses, the results were robust to assumptions regarding discount rate, trial fixed and variable costs, enrollment fraction, and the time horizon.

CONCLUSIONS
In rare diseases, evidence is often scarce and insufficient for decision making. In considering the funding of new research and patient reimbursement in rare diseases, VOI methodology may provide more relevant determinations of the value and costs of additional research, compared to standard frequentist methods.