Related Experiment Video
Updated: Dec 12, 2025
Murine Model of Leukemia Relapse to Induction Chemotherapy for Acute Lymphoblastic Leukemia
Published on: October 17, 2025
Prospective long-term follow-up after first-line subcutaneous cladribine in hairy cell leukemia: a SAKK trial
Rudolf Benz1, Kornelius Arn2, Martin Andres3
1Division of Hematology and Oncology, Kantonsspital Muensterlingen, Muensterlingen, Switzerland.
Insights
Subcutaneous cladribine offers excellent long-term disease control for hairy cell leukemia (HCL). One cycle is often sufficient, with good survival rates despite potential second malignancies.
Area of Science:
- Hematology
- Oncology
- Clinical Cancer Research
Background:
- Hairy cell leukemia (HCL) is incurable, but cladribine induces long-lasting remissions.
- Excellent long-term data exist for intravenous cladribine, but not subcutaneous administration.
Purpose of the Study:
- To analyze the long-term outcomes of classical HCL patients treated with subcutaneous cladribine.
- To evaluate the efficacy and safety of subcutaneous cladribine in a large patient cohort.
Main Methods:
- Analysis of 3 prospective multicenter clinical trials (Swiss Group for Clinical Cancer Research - SAKK).
- Inclusion of 221 patients with classical HCL treated between 1993 and 2005.
- Long-term follow-up assessing overall survival, need for second-line treatment, and secondary malignancies.
Main Results:
- Median overall survival was not reached; 1-cycle subcutaneous cladribine provided excellent outcomes.
- Poorer survival associated with pretreatment anemia, higher ECOG score, and older age.
- 23.7% required second-line treatment; 19.9% developed second primary malignancies, which were the main cause of death.
Conclusions:
- Subcutaneous cladribine is an effective first-line treatment for HCL, leading to excellent long-term disease control.
- One cycle is generally sufficient for sustained remission in most patients.
- While second malignancies occurred, their incidence was not increased compared to the general population.
Abstract:
Hairy cell leukemia (HCL) remains an incurable disease. However, first-line treatment with either intravenous or subcutaneous cladribine generally leads to long-lasting remissions. Although there are excellent long-term data for intravenous application, similar data regarding subcutaneous administration are lacking. We therefore analyzed the long-term outcome of 3 prospective multicenter clinical trials on subcutaneous cladribine performed by the Swiss Group for Clinical Cancer Research (SAKK), which recruited 221 patients with classical HCL between 1993 and 2005. Median overall survival from start of treatment was not reached. Pretreatment anemia, higher Eastern Cooperative Oncology Group score, and higher age were associated with poorer overall survival in multivariable analysis, whereas early progression at 24 and 36 months had no significant impact on overall survival. Second-line treatment was necessary in 53 (23.7%) patients after a median of 5 (range, 0.2-20.4) years, and first retreatment was mainly monotherapy with cladribine (66%) or rituximab (15.1%) or a combination of these drugs (15.1%). A total of 44 (19.9%) patients developed second primary malignancies with a median time to occurrence of 5.7 (range, 0.01-17.5) years. Second primary malignancies were the main cause for death (14; 27.5%). Compared with a matched normal Swiss population, the incidence of second primary malignancies was not increased. However, survival of patients with HCL was slightly inferior by comparison (P = .036). In conclusion, the outcome of HCL patients treated with subcutaneous cladribine is excellent, and in most patients, 1 cycle of subcutaneous cladribine is sufficient for long-term disease control.
