An Economic Analysis Assessing the Budget Impact of Introducing Glofitamab with Gemcitabine and Oxaliplatin for Autologous Stem Cell Transplant-Ineligible Relapsed/Refractory Diffuse Large B-Cell Lymphoma to a United States Health Plan
Authors: Fox David , Rosettie Katherine L , El Moustaid Fadoua , Masaquel Anthony , Cassoli Lourenia , Flowers Christopher R. 
Published: December 2024

Background:

The Phase III STARGLO trial (GO41944; NCT04408638) that evaluated glofitamab with gemcitabine and oxaliplatin (Glofit-GemOx) versus (vs) rituximab with gemcitabine and oxaliplatin (R-GemOx), met its primary endpoint of overall survival. The study enrolled patients (pts) with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) who had previously received 1 line of therapy (LoT) and were not candidates for autologous stem cell transplant (ASCT-ineligible) or had previously received ≥2 LoT. We conducted an economic analysis to assess the total cost of care among second-line (2L)+ treatment options and the budget impact of introducing Glofit-GemOx as a treatment for ASCT-ineligible R/R DLBCL to a US health plan.

Methods:

A 3-year budget impact model was developed for a hypothetical cohort of 1 million individuals enrolled in a mixed commercial/Medicare health plan. We used age distributions from US census data for insured individuals and assumed pts &lt;65 years had commercial coverage and pts ≥65 years had Medicare coverage. Comparators were axicabtagene ciloleucel (Axi-cel), lisocabtagene maraleucel (Liso-cel), tisagenlecleucel (Tisa-cel), loncastuximab tesirine (Lonca), polatuzumab vedotin + bendamustine + rituximab (Pola-BR), rituximab-based chemotherapy (R-Chemo), tafasitamab + lenalidomide (Tafa-Len), epcoritamab, and glofitamab monotherapy. R-GemOx represented the average cost of R-Chemo. DLBCL incidence rates were sourced from the SEER database (22 registries, November 2022) and the proportion of pts who received first-line, 2L, and third-line treatment were derived from projected incidence rates based on physician surveys (Kanas et al. Leuk Lymphoma 2022). Total costs included drug and administration based on treatment duration observed in pivotal trials, management of grade 3+ adverse events (AEs) occurring in ≥5% of pts in any regimen, cytokine release syndrome monitoring and routine care. Median treatment durations were converted to means using published methods (Hozo et al. BMC Med Res Methodol 2005) and the mean durations for all therapies were under 1 year, except Tafa-Len. Drug costs were sourced from the average wholesale acquisition cost reported in AnalySource® (2024) or Medicare Average Sales Price (Q2 2024). All other costs were inflated to 2024 US dollars, where applicable, and were based on published US sources. Market share projections were based on internal projections and expert opinion. AE incidence rates were sourced from each regimens' US package insert or pivotal trial. Budget impact was presented as total cumulative costs and average per-member per-month (PMPM) costs. Net budget impact was the difference in costs between the projected scenario with Glofit-GemOx and the current scenario without Glofit-GemOx. One-way sensitivity analyses (OWSA) varied inputs by ±20% to test the robustness of model results.

Results:

Of the 1 million individuals in a health plan, approximately 16 were projected to be eligible annually for treatment of R/R DLBCL after 1 LoT and ASCT-ineligible, or after ≥2 LoT. Over the model time horizon, the total cost per treated patient among the T-cell engaging treatment options was lowest for glofitamab monotherapy and Glofit-GemOx (Glofit = $226,360, Glofit-GemOx = $269,096, epcoritamab = $345,633, Liso-cel = $543,355, Axi-Cel = $549,621, Tisa-cel = $567,350; other treatments: R-Chemo = $38,528, Pola-BR = $146,637, Lonca = $219,304, Tafa-Len = $390,426). Over 3 years, the addition of Glofit-GemOx resulted in an estimated cumulative budget impact of $1,026,768 ($16,121,302 with Glofit-GemOx vs $15,094,533 without); the PMPM net budget impact was $0.0285. In the OWSA, the most influential inputs were the ASCT-ineligible proportion, the population distribution by age group, and the incidence of 2L treatment, varying the budget impact from 0.0228 to 0.0342 PMPM.

Conclusions:

The addition of Glofit-GemOx for the treatment of R/R DLBCL after 1 LoT and ASCT-ineligible or after ≥2 LoT to a US payer formulary is projected to result in a minimal budget impact of $0.0285 PMPM over 3 years. The estimated cumulative per-patient cost of Glofit-GemOx is projected to be lower than the per-patient costs of other available T-cell engaging treatment, including epcoritamab and the CAR-T therapies. The OWSA found that the model results were robust, and most sensitive to the ASCT-ineligible proportion.