Purpose: To evaluate the clinical efficacy and safety of 2-chlorodeoxyadenosine (CdA) when administered by subcutaneous injection to patients with symptomatic hairy cell leukemia (HCL), and to evaluate predictive factors for response.
Patients and methods: Seventy-three patients were given CdA as a subcutaneous injection once daily for 7 days. Complete remission (CR) required normalized blood counts and the absence of B-ly 7-positive bone marrow cells by flow cytometry. CdA concentrations in plasma following the first injection were analyzed by high-pressure liquid chromatography.
Results: Fifty-nine patients (81%) achieved a durable CR after one (n = 55) or two courses, and 10 had a partial remission (PR). With a median follow-up duration of 20 months, no patient had a clinical relapse. Neutropenic fever that required intravenous antibiotics occurred in 28 patients (38%). No toxicity at injection sites was observed. Incomplete response was predicted by an elevated lymphocyte count and serum beta 2-microglobulin level, and by a high percentage of hairy cells in the bone marrow. Plasma CdA levels were similar to those achieved from intravenous administration.
Conclusion: Subcutaneous injection of CdA is safe and as effective as continuous infusion without problems associated with the mode of administration. Our schedule simplifies CdA treatment and can be generally recommended.