Dose Escalation and Dose Expansion Study of Tirabrutinib in Combination With Other Targeted Anti-cancer Therapies in Adults With B-cell Malignancies

The primary objectives of this study are to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and preliminary efficacy of tirabrutinib (ONO/GS-4059) in combination with other targeted anti-cancer therapies and to evaluate the long-term safety of tirabrutinib as a monotherapy and in combination with other targeted anti-cancer therapies in adults with relapsed or refractory B-cell lymphoproliferative malignancies.

This study consists of three parts: Dose Escalation, Dose Expansion, and Long-term Safety Monitoring. During the Dose Escalation phase, participants will be sequentially enrolled in a standard 3 + 3 dose escalation study design, to receive oral tirabrutinib combined with idelalisib entospletinib +/- obinutuzumab. The Dose Expansion Phase will enroll additional participants with a single B-cell lymphoproliferative malignancy disease type to further evaluate efficacy, safety, tolerability, PK, and pharmacodynamics. The Long-term Safety Monitoring phase will evaluate the long-term safety of tirabrutinib both as a monotherapy and in combination with other anti-cancer therapies. As of Amendment 9, all participants currently on the study who have no clinical evidence of disease progression will transition into long-term safety monitoring. Participants from the ongoing Study GS-US-401-1787 and participants who came off Study GS-US-401-1757 and Study GS-US-401-1787 but continued to receive treatment via named patient use (or individual expanded use) will be enrolled into the long-term safety monitoring group (Group VI). Participants enrolled in Group VI will continue the same treatment regimen in Study GS-US-401-1787 or named patient use (or individual expanded use). As of Protocol Amendment 8, the maximum treatment duration for any participant is an additional 6 years from the date of this amendment (ie. until November 2025). As of Amendment 9, entospletinib will be provided until 31 December 2020 to participants who are currently receiving entospletinib. Participants treated with entospletinib as part of a combination regimen with tirabrutinib will stop receiving entospletinib by 31 December 2020 but may continue to be treated with tirabrutinib monotherapy. Idelalisib will be provided as 50 mg tablets until 31 December 2020 and 100 mg tablets until study completion. Participants assigned to the 50 mg tablet will be given the option, at the investigator's discretion, to switch to 100 mg once daily idelalisib dose.