The purpose of this study is to evaluate the safety and efficacy of parsaclisib when combined with bendamustine and obinutuzumab in subjects with relapsed or refractory follicular lymphoma (FL).

Inclusion Criteria:

• Histologically confirmed FL.
• Documented CD20+ FL.
• Relapsed or refractory to any prior rituximab-containing regimen.
• Previously treated with a maximum of 4 cancer-directed treatment regimens.
• At least 1 measurable lesion > 1.5 cm in at least 1 dimension by computed tomography or magnetic resonance imaging.
• Must be willing to undergo an incisional or excisional lymph node biopsy of accessible adenopathy or provide the most recent, available archived tumor biopsy.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2.

Exclusion Criteria:

• Clinical evidence of transformation to a more aggressive subtype of lymphoma or Grade 3B FL.

• History of central nervous system lymphoma (either primary or metastatic).

• Allogeneic stem cell transplant within the last 6 months, or active graft-versus-host disease following allogeneic transplant or autologous stem cell transplant within the last 3 months before the date of the first dose of study drug administration.

• Use of any potent cytochrome P450 3A4 inhibitors or inducers within 14 days or 5 half-lives (whichever is longer) before the first dose of study drug.

• Prior treatment with a selective PI3Kδ inhibitor or a pan PI3K inhibitor.

• Prior treatment with bendamustine (within 12 months of the start of study treatment). Subjects with prior bendamustine treatment (> 12 months before the start of study treatment) are eligible if they meet the following criteria:

  • Did not discontinue because of tolerability concerns.
  • Achieved either partial or CR to the bendamustine regimen of at least 12 months in duration before relapse/progression.
  • Experienced progression following a regimen containing an alkylating agent.

• Received prior obinutuzumab.

• Received rituximab within 4 weeks of study start.

• Prior treatment-related toxicities that have not resolved to ≤ Grade 1 before the date of study drug administration except for stable chronic toxicities (≤ Grade 2) not expected to resolve (eg, stable Grade 2 peripheral neurotoxicity).

• Received any prior monoclonal antibody (except an anti-CD20 antibody) within 90 days before the date of study start.

• History of severe allergic or anaphylactic reactions to monoclonal antibody therapy (eg, subjects in whom re-administration with rituximab would be contraindicated for safety reasons).