Benzinga | Jun 17, 2021 07:07AM EDT

Viking Therapeutics Announces Results From Phase 1 Clinical Trial Of Novel Oral Thyroid Receptor Beta Agonist VK0214; Says VK0214 'demonstrated encouraging safety and tolerability, as well as a predictable pharmacokinetic (PK) profile'

Viking Therapeutics, Inc. (Viking) (NASDAQ:VKTX), a clinical-stage biopharmaceutical company focused on the development of novel therapies for metabolic and endocrine disorders, today announced results from the company's Phase 1 single ascending dose (SAD) and multiple ascending dose (MAD) clinical trial of VK0214, a novel, orally available small molecule thyroid receptor beta (TR?) agonist in development for the potential treatment for X-linked adrenoleukodystrophy (X-ALD). In this study, VK0214 demonstrated encouraging safety and tolerability, as well as a predictable pharmacokinetic (PK) profile. The company expects to initiate a Phase 1b study of VK0214 in patients with X-ALD in the coming weeks.

The Phase 1 trial was a randomized, double-blind, placebo-controlled study in healthy volunteers. The primary objective of the study was to evaluate the safety and tolerability of VK0214 administered orally for up to 14 days. The secondary objective was to evaluate the pharmacokinetics of VK0214 following single and multiple oral doses. The first portion of the study evaluated single doses of VK0214; in the second portion of the study subjects received VK0214 once daily for 14 days. Subsequent cohorts in both parts of the study received successively higher VK0214 doses.

VK0214 was shown to be safe and well-tolerated at all doses evaluated in this study. No serious adverse events were reported, and no treatment or dose-related trends were observed for vital signs, gastrointestinal effects, cardiovascular measures, or physical examinations. VK0214 demonstrated dose-dependent exposures, no evidence of accumulation following multiple doses, and a half-life consistent with anticipated once-daily dosing regimens.

While the study's primary objective was to evaluate safety and tolerability, laboratory assessments included a lipid panel to determine potential pharmacodynamic effects following exposure to VK0214. The results showed that subjects who received VK0214 experienced reductions in low-density lipoprotein cholesterol (LDL-C), triglycerides, and apolipoprotein B following 14 days of treatment at all VK0214 doses. Many of the observed lipid reductions achieved statistical significance, though the study was not powered to demonstrate statistical significance on laboratory assessments.

% Change in Lipid Markers Following 14 Days of Treatment of VK0214



Placebo15 mg 10 mg 25 mg 50 mg 75 mg 100 mg (n=11) (n=6)(n=6) (n=6) (n=6) (n=6) (n=6)



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In addition to general lipid assessments, an evaluation of very long chain fatty acids (VLCFAs) was also performed. Despite relatively low baseline levels and the presence of a functional ABCD1 gene in these healthy volunteers, treatment with VK0214 produced reductions in VLCFA levels at all doses above 5 mg. Numerical improvements in excess of 20% from baseline were observed for multiple VLCFAs, including the key C26:0 VLCFA marker that is often elevated in patients with X-ALD, compared with a mean increase of 2.6% in placebo subjects. The VLCFA-reducing activity of VK0214 may provide benefit in a population of X-ALD patients, who by nature have high levels of accumulated VLCFAs due to pathogenic mutations in the ABCD1 gene.

"We are encouraged by the overall safety and tolerability displayed by VK0214 in this study, along with the compound's predictable pharmacokinetic profile," said Brian Lian, Ph.D., chief executive officer of Viking Therapeutics. "Additionally, we were pleased to see significant reductions in key lipids such as LDL-C and triglycerides, which suggest therapeutic activity that is similar to our other clinical-stage thyroid hormone receptor beta agonist, VK2809. We look forward to evaluating VK0214 in X-ALD patients in our planned Phase 1b study and expect to have this trial underway shortly."

Activation of the thyroid beta receptor has been shown to affect the expression of genes that are relevant to the manifestation of X-ALD. In X-ALD, mutations in the ABCD1 gene lead to dysfunction of the adrenoleukodystrophy protein (ALDP), an important peroxisomal transporter. In patients, this dysfunction leads to an accumulation of VLCFAs, which is believed to contribute to the onset and progression of the disease. Research in disease models has shown that increasing the expression of a related gene called ABCD2, which encodes a compensatory transporter called the adrenoleukodystrophy related protein (ADLRP), can result in normalization of VLCFA levels.

In preclinical studies, VK0214 has been shown to potently activate the thyroid beta receptor, a regulator of ABCD2 gene expression, leading to increased expression of ABCD2. Data from in vivo studies have demonstrated that administration of VK0214 produces a significant reduction of VLCFAs in both plasma and tissue, potentially leading to a therapeutic benefit. VK0214 has been granted orphan drug designation by the FDA for the treatment of X-ALD.