Potential association of SULT2A1 and ABCG2 variant alleles with increased risk for palbociclib toxicity.

Aim: This study evaluated associations between CYP3A4*22 and 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_rs2231137 variant 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, SULT2A1 and ABCG2 variants may be useful to individualize palbociclib dosing to minimize toxicities and improve treatment outcomes.