Subcutaneous Versus Intravenous Rituximab in Non-Hodgkin Lymphoma Treated with R-CHOP: Economic Modeling for the US

Introduction: The rituximab (RITUX) component of the R-CHOP regimen for non-Hodgkin lymphoma (NHL) consists of an intravenous (IV) initiation administration in cycle 1 followed in subsequent cycles by either: IV standard infusion (IV-S) or 90-minute (min) rapid-infusion (IV-R90), or subcutaneous (SC) administration in eligible patients. IV may be with reference rituximab (ref-RITUX) or a proposed biosimilar rituximab (biosim-RITUX). SC RITUX may offer time and cost savings; biosim-RITUX offers another potential cost-saving option. We performed a time-and-cost simulation of SC RITUX, ref-RITUX and biosim-RITUX from the US payer perspective.

Methods: Simulation analysis for one NHL patient over six cycles of R-CHOP using: [1] label-recommended administration times for all R-CHOP agents, [2] SC RITUX and ref-RITUX 1Q2018 average sales price (ASP, US$), and [3] 2018 reimbursement per Current Procedural Terminology codes (US$). Costs for the proposed biosim-RITUX were extrapolated at 1% decrements of ref-RITUX ASP from 15%-35%. IV simulations were replicated for 3 BSA-adjusted doses: small (1.6m²), average (1.85m²) and large (2.1m²) patients.

Results: Following cycle 1 IV RITUX, switching to SC saves 650 min over subsequent cycles 2-6 (or 2h10 min/cycle) compared to IV-S with ref-RITUX or biosim-RITUX at BSA=1.6m², 720 min (2h24 min/cycle) at BSA=1.85m², and 791 min (2h38 min/cycle) at BSA=2.1m²; time-savings with SC is 425min over subsequent cycles 2-6 (1h25 min/cycle) compared to IV-R90 with ref-RITUX or biosim-RITUX across all BSA.

Costs of 6 cycles of R-CHOP if switched to SC RITUX in cycles 2-6 were $54 higher compared to ref-RITUX IV-R90 but $104 lower versus ref-RITUX IV-S at BSA=1.6m²; at BSA=1.85m², costs for SC were $3,854 and $4,012 lower than ref-RITUX, respectively; at BSA=2.1m², SC saved $7,762 and $7,920 over ref-RITUX, respectively.

Compared to biosim-RITUX, costs for R-CHOP treatment with SC RITUX were higher at all decrements of biosimilar discounts at BSA=1.6m²for both IV-S (range: $3,647 to $8,649) and IV-R90 (range: $3,805 to $8,807); similarly, SC RITUX costs were higher than biosim-RITUX at all decrements of biosimilar discounts at BSA=1.85m² for both IV-S (range: $325 to $6,109) and IVR-90 (range: $484 to $6,267). At BSA=2.1m², SC RITUX costs were higher than biosim-RITUX IV-S at discounts ≥25% (from $286 @25% to $3,569 @35%) and higher than biosim-RITUX IV-R90 at discounts ≥24% (from $116 @24% to $3,727 @35%).

Conclusions: SC RITUX for R-CHOP therapy in NHL saves time compared to ref-RITUX and biosim-RITUX via IV-S or IV-R90. Compared to ref-RITUX IV-S and ref-RITUX IV-R90, SC RITUX saves costs except compared to IV-R90 in the smallest patient (BSA=1.6m²). Costs for SC RITUX were higher than biosim-RITUX IV-S and biosim-RITUX IV-R90 in both a small and an average-sized patient at all levels of biosimilar discount. In a large patient (BSA=2.1m²), biosim-RITUX saved cost versus SC RITUX if discounted at 25% for IV-S and 24% for IV-R90.