Prophylactic dexamethasone (dex) with outpatient step-up dosing (SUD) of bispecific antibodies (BsAb) in multiple myeloma (MM) vs standard of care (SOC) inpatient observation.

e19506 Background: Teclistamab (tec) and talquetamab (tal) are BsAb therapies approved for MM. Due to the risk of CRS and ICANS, the prescribing information recommends hospitalization for 48 hours after each SUD. This can be challenging for patients (pts), increasing healthcare resource utilization (HCRU) and cost. Herein, we compare the feasibility of outpt SUD using prophylactic dex and remote monitoring via Hospital at Home (HaH) at Levine Cancer Institute (LCI) to standard inpt observation at Wake Forest University. The aim was to reduce HCRU while maintaining safety. Methods: Pts at LCI received prophylactic dex 8 mg on the day after each SUD. On days between SUDs, pts were examined at home by Mobile Integrated Health, who coordinated a virtual visit with a HaH internist and calculated their ICE score. Pts were provided a thermometer, blood pressure cuff, pulse oximeter, wearable monitor for heart and respiratory rate, and an electronic tablet to input vital signs every 4 hours. Pts had virtual access to HaH nursing staff 24/7. Grade 1 CRS was managed outpt with acetaminophen and additional doses of dex, while persistent fever or higher grade CRS required evaluation at the hospital. Data related to baseline characteristics, safety outcomes, toxicity management, and HCRU were collected retrospectively for the 30 day period after starting a BsAb. Admission within 30 days was not counted towards HCRU if related to disease progression. Results: Outpatient SUD occurred for 32 pts at LCI (16 tec, 16 tal) compared to 24 pts SOC (13 tec, 11 tal). The incidence of CRS was 59% for the LCI group (max grade [G] 1 41%, G2 19%) compared to 54% of the SOC group (G1 33%, G2 12.5%, G3 4%, G4 4%). Recurrent CRS occurred in 32% of LCI pts and 46% of SOC pts. All observed ICANS was grade 1 and occurred in 6% of LCI pts v. 17% SOC. The mean dex dose per patient was 28.9 mg at LCI v. 3.3 mg for SOC. Tocilizumab use was significantly less for the outpt group with prophylactic dex (12.5% v. 42%; p = 0.03). Hospitalization within the first 30 days occurred in 47% of the LCI pts, with a mean of 1.3 inpt days per patient v. 7.7 days for SOC. Conclusions: BsAb SUDs for MM can be given outpt safely and resulted in a reduction of 6.4 hospital days per patient. While prophylactic dex did not reduce CRS incidence, all CRS was of grade 1/2, significantly less tocilizumab was used, and ICANS incidence was numerically lower compared to the SOC group. HaH cohort (n = 32) SOC cohort (n = 24) Max CRS, n (%)NoneAnyG1G2G3G4 13 (40.6)19 (59.4)13 (40.6)6 (18.8)0 (0.0)0 (0.0) 11 (45.8)13 (54.2)8 (33.3)3 (12.5)1 (4.2)1 (4.2) Recurrent CRS, n (%) 6 (31.6) 6 (46.2) ICANS, n (%) 2 (6.3) 4 (16.7) Dose delay, n (%) 9 (28.1) 7 (29.2) Tocilizumab use, n (%) 4 (12.5) 10 (41.7) Dex dose (mg), mean (range) 28.9 (8-48) 3.3 (0-40) Pts admitted, n (%) 15 (46.9) 24 (100.0) Inpatient days/patient, mean (range) 1.3 (0-8) 7.7 (5-11) Total inpatient days 42 185