Absorption, Metabolism, and Excretion of ACT-1004-1239, a First-In-Class CXCR7 Antagonist: In Vitro, Preclinical, and Clinical Data

Abstract

ACT-1004-1239 is a potent, selective, first-in-class CXCR7 antagonist, which shows a favorable preclinical and clinical profile. Here we report the metabolites and the metabolic pathways of ACT-1004-1239 identified using results from in vitro and in vivo studies. Two complementary in vitro studies (incubation with human liver microsomes in the absence/presence of cytochrome P450- [CYP] specific chemical inhibitors and incubation with recombinant CYPs) were conducted to identify CYPs involved in ACT-1004-1239 metabolism. For the in vivo investigations, a microtracer approach was integrated in the first-in-human study to assess mass balance and absorption, distribution, metabolism, and excretion (ADME) characteristics of ACT-1004-1239. Six healthy male subjects received orally 100 mg non-radioactive ACT-1004-1239 together with 1 μCi 14C-ACT-1004-1239. Plasma, urine, and feces samples were collected up to 240 h post-dose and 14C-drug-related material was measured with accelerator mass spectrometry. This technique was also used to construct radiochromatograms of pooled human samples. Metabolite structure elucidation of human-relevant metabolites was performed using high performance liquid chromatography coupled with high resolution mass spectrometry and facilitated by the use of rat samples. CYP3A4 was identified as the major CYP catalyzing the formation of M1 in vitro. In humans, the cumulative recovery from urine and feces was 84.1% of the dose with the majority being eliminated via the feces (69.6%) and the rest via the urine (14.5%). In human plasma, two major circulating metabolites were identified, i.e., M1 and M23. Elimination via M1 was the only elimination pathway that contributed to ≥25% of ACT-1004-1239 elimination. M1 was identified as a secondary amine metabolite following oxidative N-dealkylation of the parent. M23 was identified as a difluorophenyl isoxazole carboxylic acid metabolite following central amide bond hydrolysis of the parent. Other metabolites observed in humans were A1, A2, and A3. Metabolite A1 was identified as an analog of M1 after oxidative defluorination, whereas both, A2 and A3, were identified as a reduced analog of M1 and parent, respectively, after addition of two hydrogen atoms at the isoxazole ring. In conclusion, CYP3A4 contributes to a relevant extent to ACT-1004-1239 disposition and two major circulating metabolites were observed in humans.Clinical Trial Registration: (https://clinicaltrials.gov/ct2/show/NCT03869320) ClinicalTrials.gov Identifier NCT03869320.

The effect of itraconazole, a strong CYP3A4 inhibitor, on the pharmacokinetics of the first‐in‐class ACKR3/CXCR7 antagonist, ACT‐1004‐1239

“…Previous clinical investigations revealed that ≥25% of ACT‐1004‐1239 elimination goes through the primary metabolite M1, which is predominately formed by CYP3A4. 2 Therefore, a DDI study with ACT‐1004‐1239 and a strong CYP3A4 inhibitor is recommended by health authorities to investigate the extent of an increase in ACT‐1004‐1239 exposure associated with CYP3A4 interactions. There are several strong CYP3A4 inhibitors that have been previously used as perpetrator drugs in DDI studies such as ketoconazole, ritonavir, or voriconazole.…”

“…Such alternative routes may include the elimination through CYP2C19, CYP2C8, and CYP1A1, which were shown to also catalyze formation of M1 in vitro or other elimination pathways such as reduction of ACT‐1004‐1239 to the metabolite A3 as reported previously. 2 …”

“…This estimation on CYP3A4 dependency differs from the preclinical observation that revealed a 94% dependency of ACT‐1004‐1239 metabolism on CYP3A4 in vitro. 2 Given that the increase of ACT‐1004‐1239 exposure was less than fivefold and that the dependency on CYP3A4 is moderate, it is likely that other mechanisms are involved in the elimination of ACT‐1004‐1239. As reported in the human ADME study, alternative elimination pathways of ACT‐1004‐1239 encompass the excretion of unchanged parent drug, as well as biotransformation to the metabolite A3 (reduction of parent drug).…”

“…Elimination of ACT‐1004‐1239 is mainly catalyzed by CYP3A4 with the formation of the primary metabolite M1, which is a pharmacologically inactive amine metabolite formed following oxidative N‐dealkylation of parent drug and found to represent 25.1% of drug‐related material in excreta. 2 Additional metabolite profiling and identification data suggested that M1 can undergo further reactions, namely oxidative defluorination and reduction, which result in the formation of the metabolites A1 and A2, respectively. A1 and A2 represented 4.0% and 15.3% of drug‐related material in excreta, respectively.…”

“… 2 Other identified elimination pathways included reduction of ACT‐1004‐1239 to metabolite A3, which accounted for 2.7% of total drug only. 2 …”