IMPACT OF BORTEZOMIB MAINTENANCE ON MULTIPLE MYELOMA PATIENT'S SURVIVAL

Lenalidomide improves survival in multiple myeloma (MM) but is unavailable in the Brazilian public health system (SUS). Bortezomib (BTZ) was incorporated into SUS only in September 2020. Before that, transplant-eligible patients were mainly treated with CTd, and ineligible patients with MPT. Currently, VCd/VTd and VMP are the most used first-line regimens in our public hospital, with biweekly BTZ maintenance. We present 10-year updated data focusing on the impact of BTZ. To evaluate the impact of BTZ on progression-free survival (PFS) and overall survival (OS) in the overall population, in both induction and maintenance settings, and in subgroups by treatment regimen and autologous stem cell transplantation (ASCT) status. In this single-center, retrospective study, patients with newly diagnosed MM were consecutively enrolled from November 2014 to August 2025. Of 133 patients, 17 were excluded (4 due to incomplete data, 10 with asymptomatic MM, 1 with primary amyloidosis, 1 with MM-like post-transplant lymphoproliferative disorder, and 1 who had already received first-line therapy elsewhere). At the data cut-off (August 6, 2025), 100 of 116 patients (86.2%) had ≥1 year of follow-up and were analyzed. PFS was defined as the time from first-line therapy to progression, death, or last follow-up, and OS as the time from diagnosis to death or last follow-up. Median age was 63.3 years (range, 28.5–85.8), 60% were male, and 57% had the IgG subtype. The most common induction regimens were CTd (42.4%), VCd (22.2%), MPT (15.2%), VMP (6.1%), VTd (5.1%), and MP (4%). ISS stage II/III was observed in 32.8%/51.7%, and 67% were ASCT-eligible. ASCT was performed in 42.4% (42/99), 73.8% in first line. BTZ was used in induction in 36.8% (32/87), and 43.8% (14/32) of these also received BTZ maintenance; overall, BTZ maintenance was given to 40.3% (35/87). Four-year PFS was: CTd 15.2%, MPT 11.1%, VCd/VTd 48.7%, VMP not mature; median PFS for all patients was 1.6 years (95% CI 1.1–2.0). Five-year OS was: CTd 45.5%, MPT 42.1%, VCd/VTd 63.5%, VMP not mature; median OS for all patients was 3.5 years (95% CI 2.5–6.0). First-line VCd/VTd + ASCT (N = 10) achieved a 10-year OS of 100% versus a median OS of 3 years and a 2-year OS of 66.7% without ASCT (N = 3; p = 0.09). For CTd, 5-year OS was similar with or without ASCT (56.4% vs 71.4%; p = 0.296). In both regimens, first-line ASCT significantly improved PFS (VCd/VTd: p = 0.0008; CTd: p = 0.003). BTZ induction did not significantly improve 10-year OS (58.9% vs 22.7%, p = 0.74) but trended toward better 5-year PFS (42.5% vs 14.3%, p = 0.06; HR 0.94). In patients without BTZ induction, BTZ maintenance trended toward improved 4- year PFS (30.6% vs 4.24%, p = 0.07) and 4-year OS (62.9% vs 33.65%, p = 0.0546). After BTZ induction, BTZ maintenance significantly improved 2-year PFS (56.25% vs 23.9%; p = 0.0339; HR 0.371, 95% CI 0.139–0.988) and 2-year OS (82.5% vs 36.1%; p = 0.0012; HR 0.467, 95% CI 0.02–0.55). In HOVON-65/GMMG-HD4, BTZ induction plus maintenance significantly improved PFS and OS compared with non-BTZ regimens, with greater benefit in high-risk subsets, despite BTZ maintenance not being routine practice. In our resource-limited setting, BTZ induction improved 5-year OS by 21.4% versus CTd, and BTZ maintenance after BTZ induction significantly improved both PFS and OS. Where lenalidomide is unavailable, BTZ may be a viable maintenance option.