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Importance: Hand-foot syndrome (HFS) is a common adverse effect of capecitabine treatment.

Objective: To compare the incidence and time to onset of grade 2 or greater HFS in patients receiving pyridoxine vs placebo and to identify biomarkers predictive of HFS.

Design, Setting, and Participants: This single-center, randomized double-blind, placebo-controlled phase 3 trial conducted at National Cancer Centre Singapore assessed whether oral pyridoxine could prevent the onset of grade 2 or higher HFS in 210 patients scheduled to receive single-agent capecitabine chemotherapy for breast, colorectal, and other cancers.

Interventions: Patients were randomized to receive concurrent pyridoxine (200 mg) or placebo daily for a maximum of 8 cycles of capecitabine, with stratification by sex and use in adjuvant or neoadjuvant vs palliative setting. Patients were withdrawn from the study on development of grade 2 or higher HFS or cessation of capecitabine.

Main Outcomes and Measures: Primary end point was the incidence of grade 2 or higher HFS in patients receiving pyridoxine. Secondary end points included the time to onset (days) of grade 2 or higher HFS and identification of biomarkers predictive of HFS, including baseline folate and vitamin B12 levels, as well as genetic polymorphisms with genome-wide arrays.

Results: In this cohort of 210 patients (median [range] age, 58 [26-82] years; 162 women) grade 2 or higher HFS occurred in 33 patients (31.4%) in the pyridoxine arm vs 39 patients (37.1%) in the placebo arm (P = .38). The median time to onset of grade 2 or higher HFS was not reached in both arms. In univariate analysis, the starting dose of capecitabine (odds ratio [OR], 1.99; 95% CI, 1.32-3.00; P = .001), serum folate levels (OR, 1.27; 95% CI, 1.10-1.47; P = .001), and red blood cell folate levels (OR, 1.25; 95% CI, 1.08-1.44; P = .003) were associated with increased risk of grade 2 or higher HFS. In multivariate analyses, serum folate (OR, 1.30; 95% CI, 1.12-1.52; P < .001) and red blood cell folate (OR, 1.28; 95% CI, 1.10-1.49; P = .001) were the only significant predictors of grade 2 or higher HFS. Grade 2 or higher HFS was associated with 300 DNA variants at genome-wide significance (P < 5 x 10-8), including a novel DPYD variant (rs75267292; P = 1.57 x 10-10), and variants in the MACF1 (rs183324967, P = 4.80 x 10-11; rs148221738, P = 5.73 x 10-10) and SPRY2 (rs117876855, P < 1.01 x 10-8; rs139544515, P = 1.30 x 10-8) genes involved in wound healing.

Conclusions and Relevance: Pyridoxine did not significantly prevent or delay the onset of grade 2 or higher HFS. Serum and red blood cell folate levels are independent predictors of HFS.

Trial Registration: Identifier: NCT00486213

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