We performed a phase I trial of vorinostat (VOR) given on days 1 to 5 with R-EPOCH (rituximab plus etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin hydrochloride) in patients with aggressive HIV-associated non-Hodgkin lymphoma. VOR was tolerable at 300 mg and seemingly efficacious with chemotherapy with complete response rate of 83% and 1-year event-free survival of 83%. VOR did not significantly alter chemotherapy steady-state concentrations, CD4+ cell counts, or HIV viral loads. Introduction: Vorinostat (VOR), a histone deacetylase inhibitor, enhances the anti-tumor effects of rituximab (R) and cytotoxic chemotherapy, induces viral lytic expression and cell killing in Epstein-Barr virus-positive (EBV+) or human herpesvirus-8-positive (HHV-8+) tumors, and reactivates latent human immunodeficiency virus (HIV) for possible eradication by combination antiretroviral therapy (cART). Patients and Methods: We performed a phase I trial of VOR given with R-based infusional EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin hydrochloride) (n = 12) and cART in aggressive HIV-associated B-cell non-Hodgkin lymphoma (NHL) in order to identify safe dosing and schedule. VOR (300 or 400 mg) was given orally on days 1 to 5 with each cycle of R-EPOCH for 10 high-risk patients with diffuse large B-cell lymphoma (1 EBV+), 1 EBV+/HHV-8+ primary effusion lymphoma, and 1 unclassifiable NHL. VOR was escalated from 300 to 400 mg using a standard 3 + 3 design based on dose-limiting toxicity observed in cycle 1 of R-EPOCH. Results: The recommended phase II dose of VOR was 300 mg, with dose-limiting toxicity in 2 of 6 patients at 400 mg (grade 4 thrombocytopenia, grade 4 neutropenia), and 1 of 6 treated at 300 mg (grade 4 sepsis from tooth abscess). Neither VOR, nor cART regimen, significantly altered chemotherapy steady-state concentrations. VOR chemotherapy did not negatively impact CD4+ cell counts or HIV viral loads, which decreased or remained undetectable in most patients during treatment. The response rate in high-risk patients with NHL treated with VOR(R)-EPOCH was 100% (complete 83% and partial 17%) with a 1-year event-free survival of 83% (95% confidence interval, 51.6%–97.9%). Conclusion: VOR combined with R-EPOCH was tolerable and seemingly efficacious in patients with aggressive HIV-NHL.
