VKTX: Positive Results From Phase 2 Study of VK5211 in Hip Fracture

By David Bautz, PhD


Business Update

Positive Results From Phase 2 Study of VK5211 in Hip Fracture

On November 28, 2017, Viking Therapeutics, Inc. (VKTX) announced positive topline results from the Phase 2 study of VK5211, a selective androgen receptor modulator (SARM), in patients recovering from hip fracture. This was a multicenter, randomized, double blind, placebo controlled trial that enrolled a total of 108 subjects (83 women and 25 men) age ≥ 65 years of age who have suffered a hip fracture within the past three to seven weeks. Subjects were administered placebo or 0.5 mg, 1.0 mg, or 2.0 mg of VK5211 once-daily for 12 weeks (NCT02578095). The primary outcome of the trial was the change in lean body mass, less head, after 12 weeks of treatment. Secondary and exploratory endpoints included assessments of functional performance, quality-of-life, and activities of daily living.

The company is still evaluating the data package and will not receive the final data until early 2018 after all study subjects are evaluated at a 12-week follow-up. However, the data presented thus far by the company are very robust and far exceeded expectations:

➢ Placebo-adjusted increases in lean body mass, less head, were 4.8% (or 1.6 kg) at 0.5 mg (P

60 years of age of enobosarm, a SARM being developed by GTX Inc. (GTXI). The following figure shows that the highest dose of enobosarm (3 mg) resulted in an ~3% increase in lean body mass, which is less than that seen for the lowest dose of VK5211 in a similar population (Dalton et al., 2011). GTXI is developing enobosarm for treating stress urinary incontinence and breast cancer.

➢ Subjects experiencing at least a 5% increase in lean body mass, less head, were 19% with placebo, 61% at 0.5 mg (P
➢ While not powered for efficacy, numerical advantages were seen in various functional secondary endpoints, including the 6-minute walk test and short physical performance battery. These analyses were included in order to look for signals in potential outcomes for future clinical trials.

➢ There were no safety signals observed, as there were 0 drug-related serious adverse events and no difference in adverse events between placebo and active groups or between the different dosages.

Following receipt of the final data, likely in early 2018, the company will meet with the FDA to determine the path forward for a Phase 3 registration study. The full data set will likely be presented at one or more future scientific conferences, such as the 2018 American Society for Bone and Mineral Research (ASBMR) meeting, which takes place in late Sep. 2018. In addition, we believe the data likely opens the door to additional potential indications for VK5211 such as cachexia and joint replacement, although the company is currently only focusing on hip fracture recovery.


The Phase 2 data on VK5211 was better than even the most optimistic expectations, and shows that the drug has robust activity with no safety concerns thus far. We’ll be interested to see how the development path evolves once the company is able to fully evaluate the final data package. We believe partnering VK5211 with a larger pharmaceutical company is now much more likely, although with very strong data Viking should be in no rush and can wait for the most optimal terms. Based on the results, we have increased our valuation from $7 to $11 and we continue to believe that Viking’s shares are significantly undervalued.


SUBSCRIBE TO ZACKS SMALL CAP RESEARCH to receive our articles and reports emailed directly to you each morning. Please visit our website for additional information on Zacks SCR.

DISCLOSURE: Zacks SCR has received compensation from the issuer directly or from an investor relations consulting firm, engaged by the issuer, for providing research coverage for a period of no less than one year. Research articles, as seen here, are part of the service Zacks provides and Zacks receives quarterly payments totaling a maximum fee of $30,000 annually for these services. Full Disclaimer HERE.