Table 2.

DLTs during dose escalation

Dose levelPatients evaluable for DLTsPatients experiencing DLTsDLT
3-weeks-on/1-week-off dosing schedule
 50 mg41G3 mucositis
 70 mg2
 140 mg3
 260 mg4
 280 mg41G3 pulmonary embolism
 350 mg5
 400 mg41aG4 neutropenia
 600 mg121Prolonged G2 increased creatinine
 750 mg101G4 thrombocytopenia
 900 mg131G3 QTcF prolongation
 1,200 mg32G4 febrile neutropenia (n = 1)
G4 thrombocytopenia (n = 1)
Continuous dosing schedule
 600 mg61Prolonged G3 neutropenia
  • Abbreviation: G, grade.

  • aAt the ribociclib 400 mg/day dose level, a case of grade 3 hyponatremia was reported. Per protocol amendment 4, hyponatremia no longer qualifies as a DLT.