Comprehensive clinical pharmacology characterization of AZD4635 in healthy participants to support dosing considerations.

Aims: Two phase 1 studies characterized the oral bioavailability of AZD4635 (potential anticancer therapy) and factors that may influence its pharmacokinetics (PKs; food, smoking, proton-pump inhibitors [PPIs] and CYP1A2 inhibitors) to support continued clinical development of AZD4635.

Methods: Study 1 (comparative PK study; nonsmokers) consists of Part A and Part B. Participants (fasted) in Part A were administered 50 mg of AZD4635 either as nanosuspension or capsule. In Part B, these participants were administered a 50-mg capsule either following a high-fat meal or with a PPI in the fasted state. In Study 2 (CYP1A2 mediated drug-drug interaction study), a 25-mg AZD4635 capsule was administered to smokers and nonsmokers (fasted) with or without 100 mg of fluvoxamine.

Results: In Study 1 (N = 21), AZD4635 exposure was comparable between the capsule and nanosuspension. The high-fat meal produced a 12% decrease in AUC , a ≥50% reduction in C and delayed absorption (T : 4.0 h vs 1.5 h) for the capsule. The PPI did not affect the oral bioavailability of the AZD4635 capsule. In Study 2 (N = 28), AZD4635 + fluvoxamine (compared with AZD4635 alone) produced ~5-fold increases in AUC , 2-fold increases in C and prolonged AZD4635 elimination half-life in smokers (22.7 vs 9.0 h) and nonsmokers (22.4 vs 9.2 h). All treatment regimens were well tolerated. The most common adverse events included dizziness, nausea and headache.

Conclusions: The high-fat meal reduced the rate but not the extent of AZD4635 absorption. The effect of gastric pH on AZD4635 was minimal. Smoking had no effect on the exposure (C and AUC ) of AZD4635, while fluvoxamine increased AZD4635 C and total exposure. No new safety concerns were identified.