Observational Study on Treatment Adherence and Tolerability of Acalabrutinib (Drug) in Chronic Lymphocytic Leukemia (CLL)

Chronic lymphocytic leukemia (CLL) is a form of blood cancer characterized by the uncontrolled proliferation of B lymphocytes (a type of white blood cell). Treatment is usually not started until symptoms appear. The choice of medications depends on the patient’s overall health, comorbidities, and the characteristics of the CLL cells. Modern therapy includes drugs that specifically target certain structures in the malignant CLL cells. These include, among others, Bruton’s tyrosine kinase inhibitors (BTK inhibitors) such as acalabrutinib. This medication is already approved for the treatment of CLL.

The goal of the RETAIN study is to investigate how long patients continue treatment with acalabrutinib—in other words, to assess treatment adherence. At the same time, the study aims to collect additional data on tolerability, efficacy, and safety. Data will be collected for up to 40 months after the start of treatment with acalabrutinib. The primary focus of the study is treatment adherence after one year—that is, how many patients are still being treated with acalabrutinib and how many have discontinued treatment (e.g., due to side effects or disease progression) (primary endpoint). The study is purely observational and does not test a new treatment. Consequently, the study is not blinded; that is, both the patient and the doctor are aware that acalabrutinib is being taken.

Women and men aged 18 and older with chronic lymphocytic leukemia (CLL) who are starting or have recently started (within the past 28 days) treatment with acalabrutinib for their CLL are eligible to participate in the study. Acalabrutinib can be used either as first-line therapy (alone or in combination with obinutuzumab) or as second-line or subsequent therapy (after at least one prior line of therapy). If disease progression occurred during a previous BTK inhibitor treatment, patients are not eligible to participate in this study (however, discontinuation due to intolerance is not a reason for exclusion).