A phase 1b dose-escalation study of carfilzomib in combination with thalidomide and dexamethasone in patients with relapsed/refractory systemic immunoglobulin light chain amyloidosis.

Introduction: Proteasome inhibitors are the backbone of AL amyloidosis treatment - bortezomib being most widely used. Carfilzomib is a proteasome inhibitor licenced to treat multiple myeloma; autonomic and peripheral neuropathy are uncommon toxicities with carfilzomib. There is limited data on the use of carfilzomib in AL amyloidosis. Here, we report the results of a phase Ib dose-escalation study of Carfilzomib-Thalidomide-Dexamethasone (KTD) in relapsed/refractory AL amyloidosis.

Results: The trial registered 11 patients from 6 UK centres from September 2017 to January 2019; 10 patients received at least one dose of trial treatment. 80 adverse events were reported from 10 patients in the 1^st three cycles. One patient experienced dose-limiting toxicity (acute kidney injury) at a dose of 45 mg/m^2, and another patient had a SAR (fever). Five patients experienced an AE ≥ grade 3. There were no haematologic, infectious, or cardiac AE ≥ grade 3. The overall haematological response rate (ORR) at the end of three cycles of treatment was 60%.

Conclusion: Carfilzomib 45 mg/m² weekly can be safely given with thalidomide and dexamethasone. The efficacy and tolerability profile appears comparable to other agents in relapsed AL amyloidosis. These data provide a framework for further studies of carfilzomib combinations in AL amyloidosis.