A US Budget Impact Model for Selinexor in Combination with Dexamethasone for the Treatment of Patients with Relapsed or Refractory Multiple Myeloma (RRMM)
Authors: Gould Ian , Bassali Jan , Mehta Jyotsna , Shah Jatin , Mladsi Dee Dee 
Published: November 2019

BACKGROUND: Multiple myeloma is a relatively uncommon hematological cancer that occurs when the bone marrow produces malignant plasma cells that enter the blood stream. In the United States, the lifetime risk of getting multiple myeloma is 1 in 132 (0.76%). American Cancer Society estimates that about 32,110 new cases will be diagnosed and about 12,960 deaths are expected to occur among multiple myeloma patients. (American Cancer Society. Cancer Facts and Figures 2019). An increasing number of treatments are available for multiple myeloma, however, due to the highly refractory nature of the disease surviving patients must eventually resort to best supportive care (BSC). Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) for the treatment of relapsed or refractory multiple myeloma (RRMM).
OBJECTIVE: To estimate the budget impact of Selinexor in combination with dexamethasone (Sel-dex) for the treatment of patients with relapsed or refractory multiple myeloma who have received at least 4 prior therapies and whose disease is refractory to at least 2 proteasome inhibitors, at least 2 immunomodulatory agents, and an anti-CD38 monoclonal antibody in US.
METHOD: An interactive budget impact model was developed to evaluate the addition of Selinexor for treatment of RRMM using a hypothetical health plan of 25 million lives over a time horizon of 3-years (2019-2021) after the introduction of Selinexor. The model compares the formulary without Selinexor to a formulary with Selinexor and considers direct cost only. The model was developed following guidelines from the International Society for Pharmacoeconomics and Outcomes Research. The key assumptions in the model are that there is no reasonable alternative to Selinexor besides BSC, the use of Selinexor will not meaningfully reduce the cost of BSC, and the number of patients eligible to receive Selinexor is expected to remain the same for each of the 3 years evaluated in the model. The assumed uptake rates for Selinexor were included. The average per-person drug cost for each year of treatment is calculated by accounting for the cost of the drug including dosage, frequency, and duration of treatment. The costs of treatment-emergent adverse events occurring at grade 3 or higher occurring in at least 5% of patients in the STORM trial (NCT02336815) were included. As Sel-dex is taken orally, wastage was not considered for this model. Total annual treatment costs included drug costs, AE costs, and BSC costs, and were calculated for each scenario to estimate the budget impact of making Selinexor available as a treatment for eligible patients. One-way sensitivity analysis was conducted to test the robustness of the model results and the sensitivity of the results to uncertainty in key model input parameters including time on treatment with Selinexor (weeks), uptake of Selinexor in year 1 after market entry and the drug cost of Selinexor. Results were calculated in terms of total plan, per-member-per-month (PMPM), and per-treated-member-per-month costs.
RESULTS: In the hypothetical health plan of 25 million lives, the annual number of patients eligible for Selinexor was estimated to be 182. After the adoption of Selinexor, the base case results showed minimal budget impact with $0.01 per member per month incremental cost for year 1 and $0.02 for both year 2 and year 3. For Commercial and Medicare patients, the incremental cost was < $0.02 per member per month for all three years.
CONCLUSION: The results indicated that with limited treatment options in the later lines, Sel-dex for the treatment of multiple myeloma will have a minimal budget impact for a US health plan.

Disclosures
Gould: RTI International: Employment. Bassali:Karyopharm Therapeutics: Employment, Equity Ownership. Mehta:Karyopharm Therapeutics: Employment, Equity Ownership; Sanofi: Equity Ownership; Alkermes: Equity Ownership. Shah:Karyopharm Therapeutics: Employment, Equity Ownership. Mladsi:RTI International: Employment.