Folic Acid Reduces Mucositis in Metastatic Renal Cell Carcinoma Patients: A Retrospective Study.

BACKGROUND: Mucositis is often experienced in metastatic renal cell carcinoma (mRCC) patients treated with targeted therapies. This might impair daily quality of life and lead to dose reduction, discontinuation, or treatment shift. We assessed the effect of folic acid to reduce mucositis. PATIENTS AND METHODS: Patients treated with systemic therapy for mRCC who developed Grade >/=2 mucositis according to Common Terminology Criteria for Adverse Events version 4.0 (CTCAE) received oral folic acid to reduce mucositis. The medical charts were retrospectively reviewed. RESULTS: A total of 77 patients had Grade >/=2 mucositis during therapy with sunitinib (n = 29), pazopanib (n = 24), everolimus (n = 10), axitinib (n = 4), temsirolimus (n = 3), interleukin-2/interferon-alpha (n = 3), cabozantinib (n = 2), bevacizumab (n = 1), and nivolumab (n = 1). Given in doses of 1 to 5 mg daily, folic acid significantly reduced mucositis, mean CTCAE grade 0.88 (95% confidence interval [CI], 0.74-1.03) versus 2.38 (95% CI, 2.26-2.54; P < .0001). Stratified according to treatment, folic acid significantly reduced mucositis grade for sunitinib (0.97 [95% CI, 0.75-1.18] vs. 2.45 [95% CI, 2.23-2.67], P < .0001), pazopanib (0.96 [95% CI, 0.67-1.25] vs. 2.20 [2.03-2.38], P < .0001), everolimus (0.60 [95% CI, 0.10-1.10] vs. 2.60 [95% CI, 2.23-2.97], P < .0001), and other treatments (0.79 [95% CI, 0.38-1.19] vs. 2.36 [95% CI, 2.07-2.64], P < .0001). Of the 77 patients, 8 (10%) patients received dose reduction. Overall progression-free survival was 14 months and overall survival was 31 months. CONCLUSION: Folic acid reduced mucositis in mRCC patients receiving systemic therapy. This finding needs prospective validation. A double-blind, placebo-controlled prospective evaluation of folic acid is ongoing (NCT03581773).