iPSC-based Drug Repurposing for ALS Medicine (iDReAM) Study

This study consists of a phase 1 part and a phase 2 part. Phase 1 part: This is a phase 1, open-label, multicenter, dose escalation study to evaluate the safety and tolerability of bosutinib to determine the maximum tolerated dose(MTD) and a recommended phase 2 dose (RP2D) of bosutinib for treatment of ALS patients. Also, efficacy will be evaluated exploratory. Phase 2 part: This is an open label, multicenter, phase 2 part whose purpose is to evaluate the efficacy exploratorily and the long-term (for 24 weeks) safety of bosutinib for the treatment of ALS patients.

Phase 1 part: The study consists of a 12-week observation period, a 1-week (acceptable window: 5-9 days) transitional period, a 12-week study treatment period, and a 4-week follow-up period. Subjects who have been receiving riluzole since before the enrollment are allowed to continuously receive riluzole during the 12-week observation period (with the dosage remaining unchanged), and stop receiving riluzole from the beginning of the 1-week (acceptable window: 5-9 days) transitional period. After the completion of the transitional period, subjects whose total ALSFRS-R score decreased by 1 to 3 points during the 12-week observation period will receive bosutinib for 12 weeks to evaluate the safety and tolerability of bosutinib in ALS patients. All ALS drugs including riluzole will be prohibited during the bosutinib treatment period. In this study, 3 to 6 ALS patients will be enrolled in each of the 4 bosutinib dose lelvels \[100 mg/day (dose level 1), 200 mg/day (dose level 2), 300 mg/day (dose level 3), or 400mg/day (dose level 4)\] to evaluate the safety and tolerability of the investigational drug (bosutinib) under a 3+3 dose escalation study design. The dose will be escalated by 1 dose level at a time; no skipping will be allowed. Dose escalation and MTD will be determined by the safety assessment committee comprising oncologist, hematologist, ALS Expert based on the incidence of DLT in 4 weeks of treatment among 3 subjects enrolled (6 subjects if additionaly enrolled) in each dose level. RP2D will be determined by the safety assessment committee upon completion of 12-week study treatment in all subjects in all dose levels. Phase 2 part: The phase 2 part consists of 4 periods including a 12-week observation period, a 1-week (±2 days) transitional period, a 24-week study treatment period, and a 4-week safety follow-up period. After the completion of the transitional period, subjects whose total ALSFRS-R score decreased by 1 to 4 points during the 12-week observation period will receive bosutinib treatment during the 24-week study treatment period. In this study, 25 ALS patients will be enrolled; patients will be randomly assigned to the following groups: 12 patients in 200 mg/day group and 13 patients in 300 mg/daygroup of the investigational drug (bosutinib). The efficacy and the safety of bosutinib in ALS patients for 24 weeks will be assessed. The efficacy using ALSFRS-R score will be also compared with the external published data from edaravone study (MCI186-19). In order to compare with the edaravone study (MCI186-19) , the eligibility criteria of the phase 2 part is similar to those in MCI186-19. By statical allocation, approximately 85% of patients in each 200 mg and 300 mg group will have a decrease of 1-2 points in ALSFRS-R, and 15% will have a decrease of 3-4 points in ALSFRS-R, during the observation period, in accordance with MCI186-19. The efficacy using ALSFRS-R score will be also compared with matched control of Japanese Consorsium for Amyotrophic Lateral Sclerosis (JaCALS), a registory of ALS, in an exploratory manner.