Safety and Efficacy of Teclistamab in Patients With Relapsed or Refractory AL Amyloidosis.

Introduction: Teclistamab has demonstrated deep responses in patients with multiple myeloma in the MajesTEC-1 study. However, the safety and efficacy of teclistamab in patients with AL amyloidosis are unknown.

Methods: We retrospectively analyzed patients with biopsy-proven relapsed/refractory AL amyloidosis who were treated with teclistamab from December 2022 to February 2024 at the University of Pennsylvania. The data cutoff was 2/29/24. Adverse events (AE) were extracted from the electronic medical record. Patients were assessed for hematologic and organ response per consensus guidelines.

Results: Eight patients were included in this case series: median age 63 (range 59-67), 75% female, 88% White. All eight patients achieved at least very good partial response (VGPR) and had normalization of free light chains (FLC), and six (75%) patients achieved undetectable FLC levels. Of the six patients with immunofixation completed, all six (100%) achieved hematologic complete response (hCR). The median time to hematologic VGPR and hCR was 13 days (range 12-18 days) and 88 days (range 32-150 days), respectively. The median duration of follow-up was 8.5 months (range 1-14 months). Of the five patients with cardiac involvement, four (80%) achieved a cardiac response. Of the seven patients with renal involvement, two patients already achieved renal response prior to teclistamab, and of the remaining five, three (60%) achieved renal response. Six patients (75%) developed low-grade cytokine release syndrome (CRS). No patients developed ICANS. Neutropenia and AKI both occurred in 25% of patients, respectively.

Conclusions: In this series of patients, teclistamab showed outstanding depth of response and was well-tolerated. Teclistamab shows promise in treating patients with relapsed AL amyloidosis.