Safety and Efficacy of Vorinostat Plus Sirolimus or Everolimus in Patients with Relapsed Refractory Hodgkin Lymphoma

Purpose: Preclinical and early clinical data suggested that combining histone deacetylase (HDAC) and mTOR inhibitors can synergistically inhibit Hodgkin lymphoma.

Patients and Methods: During the dose-escalation study (ClinicalTrials.gov number: NCT01087554) with the HDAC inhibitor vorinostat and the mTOR inhibitor sirolimus (V+S), a patient with Hodgkin lymphoma refractory to nine prior therapies demonstrated a partial response (PR) lasting for 18.5 months, which promoted additional enrollment of patients with Hodgkin lymphoma as well as exploration of an alternative combination of vorinostat and mTOR inhibitor everolimus (V+E).

Results: A total of 40 patients with refractory Hodgkin lymphoma received V+S (n = 22) or V+E (n = 18). Patients received a median of five prior therapies, including brentuximab (n = 39), autologous stem cell transplantation (n = 26), and allogeneic stem cell transplantation (n = 12). The most frequent grade ≥3 treatment-related adverse event was thrombocytopenia in 55% and 67% of patients treated with V+S and V+E, respectively. Complete response was reported in 6 (27%) patients treated with V+S and 2 (11%) patients treated with V+E, and PR was reported in 6 patients (27%) treated with V+S and 4 (22%) patients treated with V+E (objective response rate of 55% and 33%, respectively). In summary, combined HDAC and mTOR inhibition had encouraging activity in heavily pretreated patients with relapsed/refractory Hodgkin lymphoma and warrants further investigation.

Conclusions: Combined HDAC and mTOR inhibition has salutary activity in patients with relapsed refractory Hodgkin lymphoma and warrants further investigation.