A Study of Enasidenib in People With T-Cell Lymphoma

Inclusion Criteria:

• Pathologically-confirmed AITL at the enrolling institution, with confirmed IDH2mutation (by MSK ddPCR). For R/R patients, disease must have relapsed or progressedafter at least one systemic therapy, diagnostic tumor samples have at least 5%tumor. i) IDH2 hotspot mutation confirmed by CAP/CLIA-certified NGS testing panel.Only cases with confirmed mutations detected >1% VAF will be eligible.

• Age ≥18 years at time of enrollment Previous systemic anti-cancer therapy for AITLmust have been discontinued at least 2 weeks or 5 half-lives (whichever is longer)prior to treatment. i) ii) See section 6.2 Subject Exclusion Criteria for guidelines regarding adjuvantand maintenance therapy for prior malignancy. Patients who have received localizedRT as part of their immediate prior therapy may be allowed to enroll with shorterwashout period after discussion with the MSKCC Principal Investigator ii) Patientswho have received localized RT as part of their immediate prior therapy may beallowed to enroll with shorter washout period after discussion with the MSKCCPrincipal Investigator iii) Systemic corticosteroids must be tapered to 25 mg/dayprednisone (or equivalent) upon start of investigational treatment iv) 4) 5) 6) 7)

8. 9. Topical steroids for treating cutaneous involvement of AITL is permittedPerformance status, as assessed in the ECOG grading system, ≤2 Laboratory criteria (use of GCSF and/or blood product transfusions to reach eligibility criteria must bediscussed with the MSK PI on a case-by-case basis):

Exclusion Criteria: