Results of treatment with 2-chlorodeoxyadenosine in refractory or relapsedLangerhans cell histiocytosis. Study of 9 patients

BACKGROUND: TO analyse the results of the treatment with 2-chlorcdeoxyadeno sine (2CdA) in 9 patients with refractory or relapsed Langerhans cell histi ocytosis (LCH) tracted in 8 Spanish hospitals between 1993 and 1999, PATIENTS AND METHOD: In the 9 patients the following data were recorded: ag e, sex, organ involvement by LCH, first treatment and response, dose, numbe r of cycles and schedule of administration 2CdA, response to 2CdA treatment , toxicity, disease-free survival (DFS) and overall survival (OS). RESULTS: Median age was 25 years (range, 6-63). All patients had multiorgan ic involvement by LCH, with severe organ dysfunction in 4. 2CdA was adminis tered as second line treatment in 7 cases and as third line in 2. The 2CdA dose was 0.1 mg/kg per day during 5 days in the majority of patients, and i nterval between cycles was 4 weeks. In 2 cases a complete remission (CR) wa s achieved and 4 cases attained a partial remission (PR) (overall response rate 66%). The main toxicity was hematologic, with neutropenia grade > 2 in 5 cases and thrombocytopenia > 2 in 5. Four patients had infections, with fatal evolution in one of them. After a median follow-up of 8 months (range 2-17), 2 patients remained in CR (12 months both), 4 in PR (range 2-12 mon ths) and one had active disease (17 months), The other two died due to prog ressive disease and Aspergillus spp, sepsis, respectively. The actuarial pr obabilities of DFS and OS were 58% (95% CI, 38-78%) and 71% (95% CI, 54-88% ), respectively. CONCLUSIONS: 2CdA is an active drug for patients with refractory or relapse d LCH, and its main toxicity is myelosuppression. The usefulness of 2CdA, i solated or in combination with other drugs, in patients with refractory or relapsed LCH must be assessed in controlled studies.