Observational Study of Ibrutinib Use in CLL

Inclusion Criteria:

1. Age older than 18 years.
2. Diagnosis of chronic lymphocytic leukemia, established according to iwCLL criteria (Hallek et al., 2018).
3. Presence of indications for initiating treatment as listed in iwCLL guidelines (Hallek et al., 2018) before start of ibrutinib therapy.
4. Treatment with ibrutinib per instructions for medical use of the drug, approved in the Russian Federation, is planned or this therapy has been started within 7 days before enrolment in the study (date of signing of informed consent). Simultaneously, the patient has not received ibrutinib as one of the previous lines of treatment.
5. Informed consent signed by the patient.

Exclusion Criteria:

1\. Presence of contraindications for the use of ibrutinib in accordance with the instructions, approved in the Russian Federation for the medical use of the drug, namely:

* known hypersensitivity to ibrutinib (e.g. with anaphylactic and anaphylactoid reactions);
* pregnancy and the period of breastfeeding;
* age under 18 years;
* severe renal dysfunction (creatinine clearance \<30 mL/min), incl. need for hemodialysis;
* severe liver dysfunction (Child-Pugh class C);
* concomitant use with strong inducers of the isoenzyme CYP3A (e.g., carbamazepine, rifampicin, phenytoin and drugs, containing Hypericum perforatum extract);
* concomitant use with warfarin, other vitamin K antagonists, fish oil and vitamin E preparations.