Phase I/II study incorporating intravenous hydroxyurea into high-dose chemotherapy for patients with primary...

A phase I/II study was performed to evaluate the incorporation of hydroxyurea (HU) into high-dose chemotherapy of non-Hodgkin's lymphoma (NHL).

Thirty-eight patients with primary refractory and refractory relapsed NHL were treated with carmustine (BCNU) (300 mg/m2 on day -8), cyclophosphamide (Cy) (2.5 g/m2/d on days -8 and -7), etoposide (E) (150 mg/m2 every 12 hours on days -6, -5, and -4), and HU (BCHE) with autologous hematopoietic stem-cell rescue. Twenty-one patients received HU in a dose escalation of 2 to 12 g/m2 intravenously (IV) by 72-hour continuous infusion. When the IV formulation was not available, 17 patients were given 18 g/m2 of HU orally in divided doses every 6 hours over the same 72-hour period.

The dose-limiting toxicity of 72-hour continuous infusion HU in this regimen was mucositis. Endotracheal intubation was necessary to protect the airway in two thirds of patients treated at 12 g/m2. Six patients (oral BCHE, five of 17; IV BCHE, one of 21) died with nonresponding or progressive disease and, at least in part, from the complications of the high-dose chemotherapy. Seventeen patients (45%) achieved complete remission (CR). More patients treated with IV BCHE achieved CR than patients treated with oral BCHE (12 of 21 v five of 17; P < .1, chi 2 test). Nine patients (two of 17 oral BCHE and seven of 21 IV BCHE) remain disease-free as of January 31, 1994, with a minimum follow-up time of 3 years. The lower mortality and higher response rate with IV BCHE translated into a significantly superior probability of progression-free survival (PFS) (33% at 4 year v 12% for oral BCHE; P = .048, log-rank test).

High-dose BCHE is effective treatment for primary refractory and refractory relapsed NHL. Continuous IV HU appears to be less toxic and more effective than intermittent oral HU in this regimen.