Cost utility and budget impact analysis of dexamethasone compared with bortezomib and lenalidomide for the treatment of second line multiple myeloma from a South African public health perspective

BACKGROUND: Multiple myeloma is an incurable haematological malignancy that is associated with a high probability of relapse. The survival of relapsed patients has been greatly improved by the development of novel drugs such as lenalidomide and bortezomib. We assessed the cost-effectiveness of these drugs as second-line treatment for relapsed/refractory multiple myeloma (RRMM) patients in the South African public health care system. METHODS: We modelled 3 treatment strategies for second-line RRMM treatment: dexamethasone (standard of care), bortezomib (BORT) and lenalidomide plus dexamethasone (LEN/DEX) from the South African public health perspective. For each strategy we modelled a hypothetical cohort of relapsed/refractory multiple myeloma patients using a three-state Markov model over a 15-year time horizon. Efficacy and utilization data were obtained from the MM009/010 and APEX trials and external studies. Price and cost data were from local sources and presented in 2021 South African Rands. Outcomes were reported in quality adjusted life years (QALYs). Incremental cost effectiveness ratios (ICERs) were calculated for BORT and LEN/DEX and compared to a local cost-effectiveness threshold of R38 500 per DALY averted using the assumption that 1 DALY averted is equal to 1 QALY gained. A budget impact analysis was conducted to evaluate the financial impact of the introduction of BORT and LEN/DEX, respectively. Deterministic sensitivity analysis was undertaken to account for parameter uncertainties. RESULTS: The modelled total costs of DEX, BORT and LEN/DEX were estimated to be R8 312, R234 996 and R1 135 323, respectively. DEX treatment provided 1.14 QALYs while BORT and LEN/DEX treatments provided 1.49 and 2.22 QALYs, respectively. The ICER of BORT versus DEX was R654 649 and that of LEN/DEX versus BORT was R1 225 542. Both BORT and LEN/DEX treatments were not cost-effective relative to a cost-effectiveness threshold of R38 500 per DALY averted. Both BORT and LEN/DEX significantly increase the 1 year budget-cost of RRMM treatment. CONCLUSION: Both BORT and LEN/DEX treatments are unlikely to be cost-effective strategies for second-line treatment of RRMM in South Africa. The results indicate that the drug prices of lenalidomide and bortezomib are key drivers of value for money. Price reductions could potentially make BORT more cost-effective.