Doxycycline Plus Bortezomib-Containing Regimens for the Treatment of Light-Chain Amyloidosis in the Frontline Setting: Experience from the Amyloidosis Program of Calgary.

Pre-clinical and retrospective data suggest that doxycycline added to treatment regimens has benefit in AL amyloidosis. However, a recent multicenter, open-label, randomized controlled trial in AL amyloidosis patients treated with CyBorD did not demonstrate a progression-free survival (PFS) or cardiac PFS benefit with added doxycycline. The main objective of this study was to explore the role of doxycycline combined with bortezomib-containing regimens (BCRs) for newly diagnosed AL amyloidosis patients with cardiac involvement and to compare them with a cohort of concurrent patients treated with BCR only. AL amyloidosis patients, newly diagnosed between January 2012 and March 2022, who were treated with BCR at the Amyloidosis Program of Calgary (APC) were evaluated. Sixty-four concurrent patients were identified. Thirty-nine patients received doxycycline in addition to BCR (BCR-D) for a median of 8 months. The overall response rate was similar among the groups. No significant differences in VGPR/CR, dFLC at 1 month, time to first response, time to best response, or organ responses were noted between the BCR alone and BCR-D groups. Our retrospective study demonstrated that doxycycline combined with BCR failed to prolong OS, PFS, or cardiac responses compared with BCR alone in patients with cardiac AL amyloidosis.