Real-World Step-up Dosing Practice for Patients Who Initiated Talquetamab in US Hospitals: An Analysis of the All-Payer US Hospital Administrative Premier Healthcare Database

Introduction: Talquetamab (Tal) is the first-in-class GPRC5D-targeting bispecific antibody recently approved for the treatment of patients with triple-class exposed relapsed/refractory multiple myeloma (RRMM). Initiation of Tal treatment includes step-up-dosing (SUD) prior to establishment of either a weekly (QW) or biweekly (Q2W) treatment dose schedule. However, real-world patterns of Tal SUD administration, such as site-of-care and inpatient length of stay, have been shown to vary across institutions. This study describes patterns in Tal SUD in real-world settings among US patients using the all-payer US hospital administrative Premier Healthcare Database (PHD).

Methods: Real-world de-identified data from the Premier Healthcare Database (PHD) were included for patients ≥18 years of age with RRMM who had their first hospital encounter including ≥1 Tal administration at index dose (defined as 3mg/1.5ml) between the dates of August 9, 2023 to June 1, 2024. Eligible patients had ≥1 multiple myeloma diagnosis and had not been involved in clinical trials. The index hospitalization was defined as the earliest Tal hospital encounter and the index date was that of the earliest Tal administration. Patient demographics and clinical characteristics, SUD site of care, SUD dosing schedule, inpatient length of stay (if applicable), rates of cytokine release syndrome (CRS), and tocilizumab use were reported.

Results: Overall, 108 patients with RRMM and meeting inclusion criteria were identified. Among these, 13 (12.0%) were ≥75 years of age, 71 (65.7%) were male, 60 (55.6%) were White, 93 (86.1%) were non-Hispanic, and 63 (58.3%) had coverage through Medicare. The site of care for SUD administration was solely in the outpatient setting for 14 (13.0%) patients. Of the 94 patients with ≥1 hospitalization during SUD, 14 (14.9%) patients received SUD using a hybrid model consisting of both inpatient and outpatient administrations, 37 (39.4%) received QW SUD, and 43 (45.7%) received Q2W SUD.

Overall, the mean (median) inpatient length of stay was 8.9 (8) days, declining over time from 9 (8) days between August to September 2023 to 8 (8) days between December 2023 to March 2024. Among patients who received QW SUD, 16 (43.2%) and 31 (83.8%) completed the last inpatient dose within 5 and 7 days, respectively. Among patients who received Q2W SUD, 10 (23.3%) and 35 (81.4%) completed the last inpatient dose within 7 and 10 days, respectively.

A total of 49.1% (n=53) of patients reported CRS, the majority of which were grade 1/2 (grade 1, 38.9% [n=42]; grade 2, 3.7% [n=4]; grade ≥3, 0), and 6.5% (n=7) had CRS of unknown/unspecified grade. Tocilizumab was administered for 44.4% (n=48) of patients during SUD, primarily during the first 2 SUD administrations (SUD 1, 13.9% [n=15]; SUD 2, 23.2% [n=25]; SUD 3, 7.4% [n=8]; SUD 4, 0.9% [n=1]).

Conclusions: This study reports the most recent analysis of Tal SUD patterns observed in the real world. The results found that although the majority of patients received SUD in the inpatient settings, outpatient and hybrid models for Tal SUD are emerging. Additionally, inpatient lengths of stay were observed to modestly decline over the study period. Most CRS events were of low grade and tocilizumab was mainly used for the first 2 SUD administrations, suggesting that the proportion of patients who receive Tal SUD in the outpatient or hybrid settings may increase further with time. Future real-world research will provide further insights into long-term Tal dosing schedules and treatment outcomes.