Survival and clinical response to bortezomib, thalidomide, and dexamethasone in patients with multiple myeloma at a peruvian tertiary care center: A real-world retrospective observational study

Abstract Introduction Multiple myeloma (MM) is an incurable hematologic malignancy characterized by the clonal proliferation of plasma cells. The induction regimen with bortezomib, thalidomide, and dexamethasone (VTD) has proven to be effective, particularly in patients eligible for autologous stem cell transplantation (ASCT). However, most evidence comes from studies conducted in high-income countries with greater access to modern therapies and timely transplantation. Evaluating real-world experience in resource-constrained settings is therefore essential to guide institutional clinical decision-making. This study describes the clinical characteristics, treatment responses, and progression-free survival (PFS) and overall survival (OS) outcomes in a Peruvian cohort treated with VTD as induction therapy. Methods We conducted a retrospective, single-center, observational study in adult patients with multiple myeloma who received at least four cycles of VTD between January 2019 and December 2022 at the Hospital Nacional Edgardo Rebagliati Martins, Lima, Peru. Regimens included bortezomib 1.3 mg/m² on days 1, 4, 8, and 11 or weekly; thalidomide 100 mg/day; and dexamethasone 20 mg on bortezomib days and the following day, or weekly. Responses were assessed according to the International Myeloma Working Group (IMWG) criteria. PFS and OS were estimated using the Kaplan–Meier method, with curve comparison by log-rank test and Cox regression. Results A total of 76 patients diagnosed with multiple myeloma, all treated with the VTD regimen, were included. The mean age was 62.6 years (range, 39–89 years). Males accounted for 52.6% and females for 47.4%. Age distribution showed that 9.2% were under 50 years, 36.8% were 50–60 years, 18.4% were 61–69 years, and 35.5% were 70 years or older. Regarding treatment response, very good partial response (VGPR) was achieved in 47.4% of patients, complete response (CR) in 21.1%, partial response (PR) in 21.1%, and stringent complete response (sCR) in 1.3%. Stable disease (SD) and progressive disease (PD) were each observed in 3.9% of patients, while 1.3% achieved a minimal response (MR). The most frequent baseline comorbidities were hypertension (22.4%) and diabetes mellitus (6.6%). Chronic kidney disease (CKD) was present in 10.5% of patients. At diagnosis, 23.7% with hypercalcemia (≥11 mg/dL), and 65.8% with an inverted albumin-to-globulin ratio (<1). Hematologic parameters showed anemia (hemoglobin <10 g/dL) in 73.7% of patients. Elevated lactate dehydrogenase (LDH >250 U/L) was found in 23.7%. By myeloma type, 48.7% were IgG, 30.3% IgA, and 21.1% light-chain myeloma. According to the International Staging System (ISS), 47.4% were stage III, 28.9% stage II, and 23.7% stage I. The number of VTD cycles administered ranged from 4 to 8: six cycles in 48.7% of patients, eight cycles in 28.9%, five cycles in 10.5%, four cycles in 6.6%, and seven cycles in 5.3%. A total of 33 patients (43.4%) underwent ASCT, while 56.6% did not. During follow-up, 15.8% required second-line therapy, most frequently BCD (4 patients), CRD (3), VRD (3), VCR (1), and CTD (1). With a median follow-up of 43.5 months, the median PFS was 46 months (95% CI, 31.1–60.6 months). PFS rates at 12, 24, 36, 48, and 60 months were 85.5% (95% CI, 75.4–91.7), 68.3% (56.5–77.5), 60.2% (47.8–70.5), 46.6% (31.1–60.6), and 36.7% (20.3–53.2), respectively. For OS, the median was not reached during follow-up. OS rates at 12, 24, 36, 48, and 60 months were 92.1% (95% CI, 83.3–96.4), 80.2% (69.3–87.5), 78.6% (67.5–86.3), 67.8% (53.2–78.7), and 63.0% (46.2–75.8), respectively. Overall, 27.6% of patients died during follow-up (95% CI, 17.3–37.9%), with a median time to death of 16.4 months among deceased patients. ASCT was significantly associated with a reduced risk of both progression and death. In the overall cohort (n = 76), ASCT was associated with an 80% reduction in the risk of progression (HR 0.20; 95% CI, 0.09–0.46; p < 0.001) and an 82% reduction in the risk of death (HR 0.18; 95% CI, 0.05–0.60; p = 0.005). Conclusions VTD-based regimens, regardless of dosing schedule, remain an effective first-line treatment option for multiple myeloma, particularly in healthcare systems with limited resources where access to high-cost therapies remains restricted. Furthermore, ASCT continues to be a standard consolidation strategy for eligible patients, enabling deeper responses and improving both OS and PFS.