Viking Therapeutics' Obesity Pill Shows Promise, but Safety Concerns Linger

Viking Therapeutics has released promising Phase II data for its investigational obesity pill VK2735, demonstrating significant weight loss results. However, the announcement was met with mixed reactions from investors due to safety concerns and high discontinuation rates.

Efficacy Results and Market Implications

VK2735, an oral medication that stimulates the gut hormones GIP and GLP-1, achieved a placebo-adjusted weight loss of up to 10.9% at 13 weeks in the VENTURE-Oral trial. The study, which enrolled 280 adults with obesity, showed a clear dose-response relationship, with increasing weight loss observed at doses ranging from 15mg to 120mg.

At the highest dose level of 120 mg, patients treated with VK2735 lost 12.2% of their body weight, a statistically significant result. Additionally, 80% of patients in this group achieved at least 10% weight loss, compared to only 5% in the placebo group.

These results position VK2735 among the leading oral obesity medications in development, potentially competing with offerings from pharmaceutical giants Eli Lilly and Novo Nordisk. Lilly's oral obesity drug, orforglipron, recently completed Phase III testing, while Novo Nordisk's candidate is currently under review by U.S. regulators.

Safety Profile and Investor Reactions

Despite the positive efficacy data, VK2735's safety profile has raised concerns among investors and analysts. The trial reported that 20% of patients treated with VK2735 dropped out of the study due to side effects, compared to 13% in the placebo group. Gastrointestinal issues were the predominant adverse events, with 58% of VK2735-treated patients experiencing nausea and 26% reporting vomiting.

The higher discontinuation rates, particularly at the 60 mg, 90 mg, and 120 mg doses (28%, 25%, and 38%, respectively), have dampened enthusiasm for the drug. As a result, Viking Therapeutics' stock price plummeted by approximately 40% following the announcement.

Competitive Landscape and Future Outlook

The obesity treatment market is becoming increasingly competitive, with both injectable and oral medications vying for dominance. Viking's VK2735 will need to differentiate itself from existing and upcoming treatments, such as Eli Lilly's Zepbound and Novo Nordisk's Wegovy.

One potential advantage for VK2735 is its flexible dosing strategy. The trial included a group that ramped up to the 90 mg dose and then dropped down to 30 mg after six weeks, resulting in a slight increase in weight loss from 8% to 9%. This finding suggests that transitioning patients from higher doses to lower maintenance doses could be a promising approach for long-term weight management.

Viking Therapeutics is also developing an injectable version of VK2735, with late-stage testing results expected in 2027. The company's ability to offer both oral and injectable formulations could provide it with a competitive edge in the evolving obesity treatment landscape.

As the pharmaceutical industry continues to invest heavily in weight loss medications, the success of VK2735 and similar drugs will likely depend on striking the right balance between efficacy and tolerability. The coming years will be crucial in determining which treatments emerge as leaders in this rapidly growing market.