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

ABSTRACT 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.