Population Pharmacokinetic and Exposure-Response Analyses From ALTA-1L: Model-Based Analyses Supporting the Brigatinib Dose in ALK-Positive NSCLC

Clinical Pharmacology of Brigatinib: A Next-Generation Anaplastic Lymphoma Kinase Inhibitor

Brigatinib, a next-generation anaplastic lymphoma kinase (ALK) inhibitor designed to overcome mechanisms of resistance associated with crizotinib, is approved for the treatment of ALK-positive advanced or metastatic non-small cell lung cancer. After oral administration of single doses of brigatinib 30-240 mg, the median time to reach maximum plasma concentration ranged from 1 to 4 h. In patients with advanced malignancies, brigatinib showed dose linearity over the dose range of 60-240 mg once daily. A high-fat meal had no clinically meaningful effect on systemic exposures of brigatinib (area under the plasma concentration-time curve); thus, brigatinib can be administered with or without food. In a population pharmacokinetic analysis, a three-compartment pharmacokinetic model with transit absorption compartments was found to adequately describe brigatinib pharmacokinetics. In addition, the population pharmacokinetic analyses showed that no dose adjustment is required based on body weight, age, race, sex, total bilirubin (< 1.5× upper limit of normal), and mild-to-moderate renal impairment. Data from dedicated phase I trials have indicated that no dose adjustment is required for patients with mild or moderate hepatic impairment, while a dose reduction of approximately 40% (e.g., from 180 to 120 mg) is recommended for patients with severe hepatic impairment, and a reduction of approximately 50% (e.g., from 180 to 90 mg) is recommended when administering brigatinib to patients with severe renal impairment. Brigatinib is primarily metabolized by cytochrome P450 (CYP) 3A, and results of clinical drug-drug interaction studies and physiologically based pharmacokinetic analyses have demonstrated that coadministration of strong or moderate CYP3A inhibitors or inducers with brigatinib should be avoided. If coadministration with a strong or moderate CYP3A inhibitor cannot be avoided, the dose of brigatinib should be reduced by approximately 50% (strong CYP3A inhibitor) or approximately 40% (moderate CYP3A inhibitor), respectively. Brigatinib is a weak inducer of CYP3A in vivo; data from a phase I drug-drug interaction study showed that coadministration of brigatinib 180 mg once daily reduced the oral midazolam area under the plasma concentration-time curve from time zero to infinity by approximately 26%. Brigatinib did not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, or CYP2D6 at clinically relevant concentrations in vitro. Exposure-response analyses based on data from the ALTA (ALK in Lung Cancer Trial of AP26113) and ALTA-1L pivotal trials of brigatinib confirm the favorable benefit versus risk profile of the approved titration dosing regimen of 180 mg once daily (after a 7-day lead-in at 90 mg once daily).

Brigatinib pharmacokinetics in patients with chronic hepatic impairment

Brigatinib is an anaplastic lymphoma kinase (ALK) inhibitor approved for the treatment of ALK-positive non-small cell lung cancer. This open-label, parallel-group study investigated the effect of chronic hepatic impairment on the pharmacokinetics (PK) of brigatinib to inform dosing recommendations for these patients. Participants with hepatic impairment classified according to Child-Pugh categories of mild (A), moderate (B), or severe (C) and matched-healthy participants with normal hepatic function received a single oral dose of 90-mg brigatinib. Plasma samples were collected for the determination of brigatinib plasma protein binding and estimation of plasma PK parameters. Twenty-seven participants were enrolled (Child-Pugh A-C, n = 6 each; matched-healthy participants, n = 9). The mean fraction of free plasma brigatinib was comparable for the Child-Pugh A (11.1%), Child-Pugh B (10.8%), and healthy participant groups (8.5%); free brigatinib was higher in the Child-Pugh C group (23.1%). There were no clinically meaningful effects of mild or moderate hepatic impairment on unbound systemic exposures (area under the plasma concentration-time curve [AUC]) of brigatinib (geometric least-squares mean ratios [90% CI] of 89.32% [69.79%-114.31%] and 99.55% [77.78%-127.41%], respectively). In the severe hepatic impairment group, brigatinib unbound AUC was approximately 37% higher (geometric least-squares mean ratio [90% CI] of 137.41% [107.37%-175.86%]) compared with healthy participants with normal hepatic function. Brigatinib was well tolerated in healthy participants and in participants with hepatic impairment. No dose adjustment is required for patients with mild or moderate hepatic impairment. The brigatinib dose should be reduced by approximately 40% for patients with severe hepatic impairment.

A Phase 1 Drug-Drug Interaction Study Between Brigatinib and the CYP3A Substrate Midazolam in Patients With ALK-Positive or ROS1-Positive Solid Tumors

Brigatinib is a next-generation anaplastic lymphoma kinase (ALK) inhibitor approved for the treatment of patients with ALK-positive (ALK+) non-small cell lung cancer (NSCLC). A phase 1 drug-drug interaction study was conducted to evaluate the effect of multiple-dose administration of brigatinib on the single-dose pharmacokinetics of midazolam, a sensitive cytochrome P450 3A substrate. In cycle 1, patients with ALK+ or ROS1+ solid tumors, including NSCLC, received a single 3-mg dose of midazolam as an oral solution alone on day 1 and then coadministered with brigatinib on day 21 (brigatinib 90 mg once daily on days 2-8; 180 mg once daily on days 9-28). After cycle 1, patients could continue to receive brigatinib in 28-day treatment cycles. The primary study objective was to characterize the effect of brigatinib 180 mg once daily on midazolam pharmacokinetics. The secondary objective was to assess safety. Exploratory efficacy endpoints included objective response rate and progression-free survival. Brigatinib was generally well tolerated, and safety data were consistent with the known safety profile. Among the 10 patients with ALK+ NSCLC, the confirmed objective response rate was 30% and median progression-free survival was 7.2 months. Coadministration of brigatinib reduced midazolam maximum observed plasma concentration by ≈16% (geometric least-squares mean ratio, 0.836 [90%CI, 0.662-1.056]) and area under the plasma concentration-time curve from time 0 to infinity by ≈26% (geometric least-squares mean ratio, 0.741 [90%CI, 0.600-0.915]). Thus, brigatinib is a weak inducer of cytochrome P450 3A in vivo.

Efficacy and Safety of Brigatinib Compared With Crizotinib in Asian vs. Non-Asian Patients With Locally Advanced or Metastatic ALK-Inhibitor-Naive ALK+ Non-Small Cell Lung Cancer: Final Results From the Phase III ALTA-1L Study

BACKGROUND

Brigatinib is a next-generation anaplastic lymphoma kinase (ALK) inhibitor with demonstrated efficacy in locally advanced and metastatic non-small cell lung cancer (NSCLC) in crizotinib-refractory and ALK inhibitor-naive settings. This analysis assessed brigatinib in Asian vs. non-Asian patients from the first-line ALTA-1L trial.

PATIENTS AND METHODS

This was a subgroup analysis from the phase III ALTA-1L trial of brigatinib vs. crizotinib in ALK inhibitor-naive ALK+ NSCLC. The primary endpoint was progression-free survival (PFS) as assessed by blinded independent review committee (BIRC). Secondary endpoints included confirmed objective response rate (ORR) and overall survival (OS) in the overall population and BIRC-assessed intracranial ORR and PFS in patients with brain metastases.

RESULTS

Of the 275 randomized patients, 108 were Asian. Brigatinib showed consistent superiority in BIRC-assessed PFS vs. crizotinib in Asian (hazard ratio [HR]: 0.35 [95% CI: 0.20-0.59]; log-rank P = .0001; median 24.0 vs. 11.1 months) and non-Asian (HR: 0.56 [95% CI: 0.38-0.84]; log-rank P = .0041; median 24.7 vs. 9.4 months) patients. Results were consistent with investigator-assessed PFS and BIRC-assessed intracranial PFS. Brigatinib was well tolerated. Toxicity profiles and dose modification rates were similar between Asian and non-Asian patients.

CONCLUSION

Efficacy with brigatinib was consistently better than with crizotinib in Asian and non-Asian patients with locally advanced or metastatic ALK inhibitor-naive ALK-+ NSCLC. There were no clinically notable differences in overall safety in Asian vs. non-Asian patients.