Low Beclin-1 expression predicts improved overall survival in patients treated with immunomodulatory drugs for multiple myeloma and identifies autophagy inhibition as a promising potentially druggable new therapeutic target: an analysis from The Austrian Myeloma Registry (AMR).

Beclin-1 is a key regulator of autophagy and has been suggested to be involved in the development of drug resistance in multiple myeloma (MM). We analyzed the expression of Beclin-1 in a retrospective cohort of 70 MMs. Beclin-1 expression did not influence overall survival (OS) and progression-free survival (PFS) in patients with therapy-naïve MM. In patients treated with immunomodulatory drugs (IMiDs) lack of or low Beclin-1 expression resulted in a significantly improved OS and PFS compared to those treated with bortezomib or nonnovel agents. Beclin-1 expression was more frequently detected in relapsed MM than in therapy-naïve MM probably being a hallmark of tumor progression and therapy resistance. If validated prospectively, Beclin-1 expression might identify patients prone to profit above average from IMiDs and enable a more rational allocation of antimyeloma therapies. Furthermore, the inhibition of autophagy could be a new promising target to improve response to treatment in the relapsed/refractory setting.