Background: In our recent study, fixed duration BsAbs (glofitamab [Glofit] and mosunetuzumab [Mosun]) with less frequent dosing were associated with lower travel burden vs treat-to-progression epcoritamab (Epcor) with more frequent dosing (Huntington et al. ASH 2024). The current study aimed to characterize the real-world travel burden of BsAbs using a larger cohort and to identify potential inequities in this burden among patients (pts) with DLBCL or FL treated with BsAbs in the US.

Methods: Travel burden was estimated using the 100% Medicare Fee-For-Service database. Pts diagnosed with DLBCL or FL between Jan 1, 2022 and Dec 31, 2024, with ≥1 claim for Glofit, Mosun, or Epcor were included. Mean travel burden was quantified by one-way travel distance (miles) and one-way travel time (minutes [mins]) from pts' residential ZIP code to their treatment site. Pts with a one-way travel distance ≥1000 miles were excluded to avoid potential misclassification. Descriptive statistics were conducted to explore the associations between patient- and county-level socioeconomic status (SES) variables with one-way travel distance and time.

SES variables included patient-level data from Medicare (including age, gender, race/ethnicity, and dual eligibility status) and county-level variables from US Census and American Health Resource Files mapped to patient-level data. Multivariable analyses (MVA) included linear regression models; log-transformation was conducted as a sensitivity analysis due to the right-skewed distributions of one-way distance and time.

Results: The analysis included 1039 pts who received BsAbs during the study period (Glofit for DLBCL, n=322; Epcor for DLBCL, n=417; Mosun for FL, n=254; Epcor for FL, n=46; after excluding 16 pts with a one-way travel distance of ≥1000 miles). The total number of BsAb administrations across a mean follow-up of 6.2 months for all included pts was 8213. In the overall sample, 82% of pts were White, mean (standard deviation [SD]) age was 74.7 (8.4) years, 71% had DLBCL, and the highest proportion of pts lived in the South (29%) and Northeast (27%). Mean (SD) one-way travel distance and time for all BsAb administrations was 54.7 (94.1) miles and 61.5 (84.5) mins, respectively. Overall, 54%, 21%, and 25% of administrations involved travelling <30 miles, 30–60 miles, >60 miles, respectively; 39%, 30%, and 31% of administrations involved travelling <30 mins, 30–60 mins, and >60 mins, respectively.

In the linear regression models, pts living in rural areas traveled an additional 56.1 (95% confidence interval [CI]: 39.6, 72.6) miles and 53.9 (39.1, 68.7) mins vs pts living in urban areas. Pts living in the Northeast and Midwest traveled 36.0 (95% CI: -51.0, -21.1) and 21.4 (-36.8, -6.0) fewer miles, and 29.8 (-43.3, -16.4) and 20.8 (-34.6, -7.0) fewer mins, respectively, vs pts living in the South. Pts living in counties with hospital oncology services traveled 17.7 (95% CI: -34.2, -1.2) fewer miles vs pts living in counties without these services. These variables were also associated with one-way travel distance and time in the log-transformed models, which showed a higher goodness of fit (R2=0.23–0.26) vs the linear regression models (R2=0.12–0.13). The following variables were also associated with one-way travel distance and time in the log-transformed models (exponentiated parameter estimate [95% CI]): for every increase in age by 1 year, travel distances and times decreased by 1% (0.99 [0.98, 1.00] and 0.99 [0.99, 1.00], respectively); female pts traveled 16% fewer miles (0.84 [0.74, 0.96]) and 11% fewer mins (0.89 [0.81, 0.98]) vs male pts; pts living in counties with higher education rates traveled 23% fewer miles (0.77 [0.62, 0.97]) vs pts living in counties with lower education rates; and White pts traveled 22% more miles (1.22 [1.02, 1.46]) and 16% more mins (1.16 [1.02, 1.33]) vs people of color.

Conclusions: In this real-world study of Medicare beneficiaries, travel burden varied among pts receiving BsAbs for DLBCL and FL. Travel burden was greater for pts living in areas that were rural, lacked hospital oncology services in their county, or lived in the Southern region of the US. For pts who face higher travel-related barriers, factors associated with lower travel burden overall, such as fixed duration BsAbs with less frequent dosing, may be important to consider. Future work evaluating receipt of BsAbs as the primary outcome will help clarify inequities in access to care.

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2025
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