A Study of Duvelisib in Participants With Relapsed or Refractory Peripheral T-cell Lymphoma (PTCL)

Inclusion Criteria:

1. Age ≥ 18 years of age
2. Diagnosis of one of the following histologic subtypes of PTCL, pathologically confirmed, as defined by the World Health Organization:

   1. Peripheral T-cell lymphoma-not otherwise specified;
   2. Angioimmunoblastic T-cell lymphomas;
   3. Anaplastic large cell lymphoma (ALCL); or
   4. Natural-killer/T-cell lymphoma
3. Received at least 2 cycles of one standard regimen for newly diagnosed advanced PTCL, and one of the following:

   1. failed to achieve at least a PR after 2 or more cycles of standard therapy;
   2. failed to achieve a CR after completion of standard therapy; and/or
   3. persistent or progressive disease after an initial response
4. For participants with CD30+ ALCL, failed or are ineligible or intolerant to brentuximab vedotin
5. Measurable disease as defined by Lugano for PTCL, that is, at least 1 measurable disease lesion \> 1.5 centimeters in at least one dimension by conventional techniques (fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography \[CT\], CT with contrast, magnetic imaging resonance)

Exclusion Criteria:

1. Primary leukemic PTCL subtypes (that is, T-cell prolymphocytic leukemia, T-cell large granular lymphocytic leukemia, adult T-cell leukemia/lymphoma and aggressive NK-cell leukemia) or transformed mycosis fungoides
2. Received prior allogeneic transplant
3. Received prior treatment with a PI3K inhibitor
4. Known central nervous system involvement by PTCL
5. Ongoing treatment with chronic immunosuppressants (e.g., cyclosporine) or systemic steroids \> 20 mg of prednisone (or equivalent) once daily
6. Ongoing treatment for systemic bacterial, fungal, or viral infection at Screening
7. Known hypersensitivity to duvelisib and/or its excipients