The most common toxicities associated with TAS-102 were neutropenia (RR 116.51, 95% CI 23.51-577.33), leucopenia (RR 67.70, 95% CI 13.63-336.29), anemia (RR 4.28, 95% CI 2.70-6.79) and diarrhea (RR 5.10, 95% CI 1.40-18.61).
To evaluate the association between efficacy and neutropenia, patients were divided into 4 categories according to the grade of neutropenia during the first cycle of TAS-102: Category A (grade 0-1), B (grade 2-4), C (grade 0-2), and D (grade 3-4).
Certain subpopulations appear to benefit more than others from TAS-102; those that benefit often have underlying genetic defects in DNA repair pathways and/or develop neutropenia.