Clinical Characteristics, Cytogenetic Risks, and Prognoses of Young Multiple Myeloma Patients in the Era of Novel Therapies

<b>Background/Objectives:</b> In recent years, there have been significant advances in the understanding and treatment of multiple myeloma (MM). Despite this progress, there is still limited information on the disease in patients aged 50 or younger, including the impact of young age on disease characteristics, treatment, and outcome. <b>Methods:</b> In this retrospective study, we analyzed 68 newly diagnosed MM patients aged ≤ 50 years (y) who had undergone at least one peripheral blood stem cell transplantation (PBSCT). Additionally, we reviewed data published during 2008-2022 and compared these to our cohort. <b>Results:</b> Of note, the disease characteristics in our cohort were similar to those in older patients. However, the incidence of bone lesions was higher in younger patients (84%). Moreover, 33% had LC-only MM and 7% had high-risk (del17p, t(14;16), t(4;14)) cytogenetics. Advanced ISS and R-ISS II/III were observed in 57% and 78%, respectively. Therapy was intense, with 53% of patients undergoing ≥2 SCTs. Median follow-up was 75 months, median progression-free survival was 57 months, and median overall survival (OS) was not reached. The 10-year OS rate was 72%, with only 19% succumbing to the disease. Notably, no specific therapeutic regimen or risk factors for worse outcomes were identified through uni- or bivariate analyses, even in subgroup analyses of younger patients aged ≤ 40 y. <b>Conclusions:</b> Our, and prior, results of young (<50 y) and very young (<40 y) MM patients underscore the need for further comprehensive studies focused on this significantly affected cohort.