PTC Therapeutics has plans to submit a new drug application for vatiquinone, a small molecule inhibitor of 15-lipoxygenase in development for patients with Friedreich ataxia, in late 2024.
In a phase 1, 2-part, open-label, fixed-sequence, single and multiple oral dose study newly published in Clinical Pharmacology in Drug Development, results showed that the pharmacokinetics of vatiquinone (PTC Therapeutics) a small molecule inhibitor of 15-lipoxygenase in development for patients with Friedreich ataxia (FA), can be adjusted by coadministration of cytochrome P450 isoform 3A4 (CYP3A4) inhibitor itraconazole or CYP3A4 inducer rifampin.1
Coadministration of vatiquinone 400 mg with itraconazole 200 mg increased maximum observed concentration (Cmax) of vatiquinone and systemic exposure (AUC0-inf) by approximately 3.5- and 2.9-fold, respectively. The coadministration of vatiquinone 400 mg with rifampin 600 mg decreased vatiquinone Cmax and AUC0-inf by approximately 0.64- and 0.54-fold, respectively. Notably, the terminal half-life of vatiquinone was not influenced by neither itraconazole or rifampin.
“Vatiquinone has demonstrated a very well-established safety profile in children, including very young children with severe illnesses, as well as in adults in clinical studies," Matthew B. Klein, MD, MS, FACS, chief executive officer at PTC Therapeutics, told NeurologyLive®. "The pharmacology results shared in the publication should not impact the exposure, safety, or use of vatiquinone but can provide guidance for physicians when considering other medications that patients may be receiving."
In this study, investigators assessed the effect of itraconazole and rifampin on the single-dose PKs of vatiquinone. Researchers enrolled participants between 18 and 45 years of age, with a body mass index of 18.5-30 kg/m2. On the first day of each part of the study, patients only received a single dose of vatiquinone 400 mg, which was followed by a washout of 7 days. In Part 1, patients received itraconazole on days 8 through 11, and they received vatiquinone coadministered with itraconazole on day 12, followed by a last dose of itraconazole on day 13. In Part 2, patients received rifampin on days 8 through 21, and then received vatiquinone coadministered with rifampin on day 22, followed by a last dose of rifampin on day 23.
“The clinical study results confirm that the CYP3A4 enzyme plays an important role in vatiquinone metabolism and the effect on vatiquinone PK when coadministered with a potent CYP3A4 inhibitor or inducer. Additional work was performed to understand the impact of moderate CYP3A4 inhibitors and inducers on vatiquinone exposures via physiologically based pharmacokinetic modeling and will be presented elsewhere,” coauthor Lee Golden, MD, chief medical officer at PTC Therapeutics, and colleagues wrote.1
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Although 3 patients (13.04%) reported 4 treatment-emergent adverse events (TEAEs), investigators observed no treatment-emergent serious adverse events (TESAEs) during the study. Only 2 participants experienced temporary clinically significant elevations in hepatic enzymes. As for the reported TEAEs, they were in the Gastrointestinal System Organ Class (SOC) and, for 1 patient, also in the Nervous System SOC.
Authors noted that all TEAEs were mild and resolved by the completion of the study or shortly thereafter. The reported TEAES were considered unrelated to vatiquinone although the elevated alanine transaminase and aspartate transaminase enzymes might have possibly been related to itraconazole, according to the principal investigator of the study.1
“The results of this analysis together with phase 3 efficacy and safety data, population PK analysis, and the exposure-response relationship will determine if the extent of vatiquinone changes in the presence of CYP3A4 inhibitors and inducers are considered clinically relevant,” Golden et al noted.1 According to a recent company update, PTC Therapeutics has plans to submit a new drug application (NDA) for vatiquinone for the treatment of FA in late 2024.2
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"The recently completed MOVE-FA placebo-controlled study results demonstrate a statistically significant and meaningful effect on the upright stability subscale of the disease rating scale – the most relevant and sensitive component of the disease rating scale for pediatric and young adult ambulatory patients," Klein said. "The results in the study support that vatiquinone could have an important effect in delaying loss of ambulation as well as other important and burdensome aspects of the disease."
Conducted by lead author David Lynch, MD, PhD, a neurologist and director of the Friedreich's Ataxia Program at Children's Hospital of Philadelphia, and colleagues, the trial included patients 143 aged at least 7 years, with an mFARS score of between 20 and 70 and the ability to ambulate at least 10 feet in 1 minute with or without assistance. The primary end point of the current analysis was placebo-corrected change from baseline in mFARS at 72 weeks. The intent-to-treat (ITT) population had a mean age of 18.7 years and the primary analysis population—the mITT population—included participants between 7 years and 21 years of age (mean, 14.6).
Investigators observed a nominally significant benefit recorded in the Upright Stability subscale (USS), a relevant metric of disease progression in younger ambulatory patients with FA, of mFARS, with a change of –1.26 (P = .021). In addition, researchers observed nominally significant benefit in the Modified Fatigue Impact Scale, with a change of –5.05 (P = .025). Overall, the authors noted that the treatment was safe and well tolerated among the participants, with no differences in treatment-related adverse events observed between treatment and placebo groups.
"The effects observed in this trial along with the established safety profile will form the basis of the planned vatiquinone NDA submission later this year," Klein added.
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