Vincristine dose adjustments in adult acute lymphoblastic leukemia: impact on treatment outcomes and neuropathy

Vincristine remains central in adult acute lymphoblastic leukemia (ALL) therapy but frequently requires dose adjustments due to toxicity. We retrospectively analyzed 96 adults (median age 29.5 years, range 17-68) treated from 2014-2023 at a Mexican tertiary center. Overall, 79.2% had at least one vincristine dose reduction, more frequent with pediatric-inspired regimens (87.3% vs. 63.6%, OR 3.93, 95% CI 1.41-10.96, <i>p</i> = 0.015). Clinically significant peripheral neuropathy (PN) was reported in 35.1% before maintenance and persisted in 37% at last follow-up, associated with age ≥30 years (OR 6.78, 95% CI 2.07-22.2, <i>p</i> = 0.002) and cumulative vincristine >53 mg (OR 5.29, 95% CI 1.41-19.85, <i>p</i> = 0.014). Despite these adjustments, outcomes were unaffected: median OS was 55.2 months with dose reduction vs. 44.5 months without (HR 0.87, <i>p</i> = 0.707), and median EFS 40.1 vs. 19.0 months (HR 0.64, <i>p</i> = 0.158). Vincristine reductions did not compromise survival, supporting reevaluation of dosing to balance efficacy and long-term toxicity.