Potential association of SULT2A1and ABCG2variant alleles with increased risk for palbociclib toxicity

Aim:This study evaluated associations between CYP3A4*22and variants in other pharmacogenes (CYP3A5, SULT2A1, ABCB1, ABCG2, ERCC1) and the risk for palbociclib-associated toxicities.Materials & methods:Two hundred cancer patients who received standard-of-care palbociclib were genotyped and associations with toxicity were evaluated retrospectively.Results:No significant associations were found for CYP3A4*22, CYP3A5*3, ABCB1_rs1045642, ABCG2_rs2231142, ERCC1_rs3212986 and ERCC1_rs11615. Homozygous variant carriers of SULT2A1_rs182420 had higher incidence of dose modifications due to palbociclib toxicity (odds ratio [OR]: 4.334, 95% CI: 1.057–17.767, p = 0.042). ABCG2_rs2231137variant carriers had borderline higher incidence of grade 3–4 neutropenia (OR: 4.14, 95% CI: 0.99–17.37, p = 0.052).Conclusion:Once validated, SULT2A1and ABCG2variants may be useful to individualize palbociclib dosing to minimize toxicities and improve treatment outcomes.