Ibrutinib does not have clinically relevant interactions with oral contraceptives or substrates of CYP3A and CYP2B6

Ibrutinib: Pediatric First Approval

Ibrutinib (IMBRUVICA^®), a small molecule inhibitor of Bruton's tyrosine kinase (BTK) developed by Pharmacyclics, Inc. and Janssen Pharmaceutical, is well established as a treatment for B-cell malignancies and is also approved in the USA in adult patients with chronic graft-versus-host disease (cGVHD) and in Japan in adults and adolescents aged ≥ 12 years with cGVHD. Ibrutinib was approved in August 2022 in the USA for use in pediatric patients with cGVHD after failure of one or more lines of systemic therapy and is the first treatment approved for use in this group of patients aged < 12 years (ibrutinib is now indicated for the treatment of adult and pediatric patients aged 1 year and older with cGVHD after failure of one or more lines of systemic therapy). This article summarizes the milestones in the development of ibrutinib leading to this pediatric first approval for the treatment of patients with cGVHD.

Ibrutinib does not have clinically relevant interactions with oral contraceptives or substrates of CYP3A and CYP2B6

Ibrutinib may inhibit intestinal CYP3A4 and induce CYP2B6 and/or CYP3A. Secondary to potential induction, ibrutinib may reduce the exposure and effectiveness of oral contraceptives (OCs). This phase I study evaluated the effect of ibrutinib on the pharmacokinetics of the CYP2B6 substrate bupropion, CYP3A substrate midazolam, and OCs ethinylestradiol (EE) and levonorgestrel (LN). Female patients (N = 22) with B‐cell malignancies received single doses of EE/LN (30/150 μg) and bupropion/midazolam (75/2 mg) during a pretreatment phase on days 1 and 3, respectively (before starting ibrutinib on day 8), and again after ibrutinib 560 mg/day for ≥ 2 weeks. Intestinal CYP3A inhibition was assessed on day 8 (single‐dose ibrutinib plus single‐dose midazolam). Systemic induction was assessed at steady‐state on days 22 (EE/LN plus ibrutinib) and 24 (bupropion/midazolam plus ibrutinib). The geometric mean ratios (GMRs; test/reference) for maximum plasma concentration (C_max) and area under the plasma concentration‐time curve (AUC) were derived using linear mixed‐effects models (90% confidence interval within 80%‐125% indicated no interaction). On day 8, the GMR for midazolam exposure with ibrutinib coadministration was ≤ 20% lower than the reference, indicating lack of intestinal CYP3A4 inhibition. At ibrutinib steady‐state, the C_max and AUC of EE were 33% higher than the reference, which was not considered clinically relevant. No substantial changes were noted for LN, midazolam, or bupropion. No unexpected safety findings were observed. A single dose of ibrutinib did not inhibit intestinal CYP3A4, and repeated administration did not induce CYP3A4/2B6, as assessed using EE, LN, midazolam, and bupropion.