Background: Most patients with MM eventually become refractory to the three main therapy classes used to treat the disease: proteasome inhibitors (PIs), immunomodulatory drugs (IMiDs), and anti-CD38 monoclonal antibodies (mAbs). The objective of the present study was to describe the management of patients who have become TCR and how treatment strategies vary across countries. Methods: A retrospective chart review study was conducted across the US, Canada (CA), the UK, France (FR), Germany (DE), Spain (ES), Belgium (BE), the Netherlands (NL), and Sweden (SE). Oncologists/hematologists were recruited to abstract medical chart information from eligible patients (eg, diagnosed with MM, clinician-reported refractoriness to ≥1 IMiD, ≥1 PI, and ≥1 anti-CD38 antibody treatment) into an electronic case report form. Patients had to initiate their first (index) therapy after becoming TCR between 11/1/2015 and 12/31/2019. Chart abstractions were performed from February through October 2022. Demographics, baseline clinical characteristics, and treatment patterns were descriptively analyzed. Results: A total of 718 patients with TCR MM were included (61.4% male; median age at index = 64.2 years); 25.8% had an ECOG score of 2 and 28.7% had high cytogenetic risk [ie, t(4:14), t(14:16), and/or del(17p)]. Patients received a median of 3 treatment lines prior to their index therapy (19.4% were penta-exposed). In the post TCR setting, the most frequently used treatments included IMiDs (52.5%), PIs (40.8%), chemotherapy (CT; 27.3%), and mAbs (16.3%). Treatment class usage also varied significantly by country (Table 1). Conclusions: Our global chart review indicated that many patients reach TCR status after only a few lines of therapy and, after this point, retreating with IMiDs, PIs, and mAbs was common practice. The diversity of treatment classes used in this setting underscores the challenges across countries with managing a TCR population due to the lack of a clear standard of care.

Note: ‘other’ includes panobinostat, elotuzumab, venetoclax, pembrolizumab, and clinical trial agents BCMA, B-cell maturation antigen; SINE, selective inhibitors of nuclear export.