Safety
deaths, diarrhea, abdominal pain, Treatment-related adverse eventsDose reductions, decreased white blood, weight loss
ADVERSE EVENTS, ADVERSE EVENT, PALMAR-PLANTAR ERYTHRODYSESTHESIA SYNDROME
All the 41 patients who received at least one dose of the study drug had experienced at least one treatment-related adverse event (TRAE) during the study treatment, and 34 (82.9%) and five (12.2%) of them had TRAEs of grade 3 and 4, respectively. No grade 5 AEs were reported (Table Treatment-related adverse eventsDose reductions were required in 12 patients. Ten patients needed to reduce the dose of dalpiciclib to 100 mg/d, mostly due to decreased white blood cells and decreased neutrophil count, and three of them required a second dose reduction to 75 mg/d. Dose reductions of pyrotinib to 320 mg/d were recorded in four patients, and reasons for dose adjustments included diarrhea, weight loss, palmar-plantar erythrodysesthesia syndrome, decreased white blood cells, and decreased neutrophil count. There were two treatment-related serious adverse events (one abdominal pain and one decreased cardiac ejection fraction), and one of them (decreased cardiac ejection fraction) led to discontinuation of pyrotinib consequently. No treatment-related deaths occurred.Of nine patients who experienced diarrhea of grade 3, two experienced more than once. The median time to the first onset of grade 3 diarrhea was 58 days (range = 3–231), and the median cumulative duration of grade 3 diarrhea was 2 days (range = 1–6). A dose reduction of pyrotinib related to diarrhea was reported in one patient. No dose discontinuation was related to diarrhea.