Phase 2 Trial of the Farnesyltransferase Inhibitor Tipifarnib for Relapsed/Refractory Peripheral T Cell Lymphoma

A phase 2, international, open-label, non-randomized, single-arm trial was conducted to evaluate the efficacy and safety of tipifarnib, a farnesyltransferase inhibitor, as monotherapy for relapsed/refractory peripheral T-cell lymphoma (PTCL) and to evaluate tumor mutation profile as a biomarker of response. Adults with relapsed/refractory PTCL received tipifarnib 300 mg orally twice daily for 21 days in a 28-day cycle. The primary endpoint was objective response rate (ORR); secondary endpoints included ORR, progression-free survival (PFS), duration of response (DOR), and adverse events (AEs) in specific subtypes. Sixty-five patients with PTCL were enrolled: n=38 angioimmunoblastic T-cell lymphoma (AITL), n=25 PTCL not otherwise specified (PTCL-NOS), and n=2 other T-cell lymphomas. The ORR was 39.7% (95% CI, 28.1-52.5) in all patients and 56.3% (95% CI, 39.3-71.8) for AITL. Median PFS was 3.5 months overall (954% CI, 2.1-4.4), and 3.6 months (95% CI, 1.9-8.3) for AITL. Median DOR was 3.7 months (95% CI, 2.0-15.3), and greatest in AITL patients (7.8 months; 95% CI, 2.0-16.3). The median overall survival was 32.8 months (95% CI, 14.4 to not applicable). Tipifarnib-related hematologic AEs were manageable and included: neutropenia (43.1%), thrombocytopenia (36.9%), and anemia (30.8%); other tipifarnib-related AEs included nausea (29.2%) and diarrhea (27.7%). One treatment-related death occurred. Mutations in RhoA, DNMT3A, and IDH2 were seen in 60%, 33%, and 27%, respectively, in the AITL tipifarnib responder group vs 36%, 9%, and 9% in the non-responder group. Tipifarnib monotherapy demonstrated encouraging clinical activity in heavily pre-treated relapsed/refractory PTCL, especially in AITL, with a manageable safety profile. ClinicalTrials.gov NCT02464228