Viking Therapeutics stock crashed over 33% after the drugmaker released study results of its experimental weight-loss pill, indicating the data was way worse than investors had hoped for.

In a mid-stage clinical trial, VK2735 which is taken once daily as a pill resulted in an average weight reduction of 12.2% in patients taking the highest dose over a 13 week period. Patients on placebo lost 1.3% of their weight. Nearly a third of patients discontinued the treatment, suggesting side effects may be a concern.

Expectations for the obesity pill had been high. The next frontier in the highly lucrative market for GLP-1s -- a gut hormone that helps control blood sugar levels and suppresses appetite -- is an oral version of injectable drugs which have had blockbuster success. Pills are likely to be more popular with consumers and could be easier to distribute and don't need to be refrigerated.

Earlier this month, Eli Lilly said patients on the highest dose of its oral medicine orforglipron lost 12.4% of their weight on average over 72 weeks, compared with patients on the placebo, who lost 0.9%. The result disappointed and Lilly shares dropped double digits on the news.