Structure Therapeutics’ lead drug candidate is chasing big pharmaceutical rivals in the race for new oral weight-loss medications, and the company had been telling investors to expect data late this year from an early-stage study and a mid-stage clinical trial. A snafu is delaying the mid-stage study, but the early-stage trial has preliminary data suggesting Structure’s molecule could be competitive with others, results enabling the company to raise $300 million in new capital.
The Structure drug, GSBR-1290, binds to GLP-1, the same receptor targeted by Novo Nordisk products Ozempic and Wegovy as well as Mounjaro from Eli Lilly. Those large molecule biologics are administered as injections. Structure’s small molecule drug could offer patients the convenience of a once-daily pill.
After completing a Phase 1 test in healthy volunteers last year, South San Francisco-based Structure proceeded to a Phase 1b study enrolling healthy individuals who are overweight or obese. The 24 participants were randomly assigned to receive one of three doses of Structure’s drug or a placebo. According to the preliminary data reported Friday, patients lost an average 4.9 kilograms (about 10.8 pounds ) compared to baseline and a placebo. As with the prior Phase 1 study, the Structure drug was safe and well tolerated. The most common adverse events in Phase 1b were nausea and vomiting, which were more prevalent in the two higher doses tested. Liver tests showed no elevated levels of enzymes that can be a sign of drug toxicity. No participants dropped out of the clinical trial.
The caveat here is it’s a small study and the preliminary results are for a short period of time—just four weeks. Structure had planned a late fourth quarter data reveal from this study alongside Phase 2a results from a 12-week study in obesity and type 2 diabetes. But in a glaring omission for a study assessing weight loss, one of the clinical trial sites failed to collect weight data at week 12 for 24 of the 40 enrolled participants. This oversight means the obesity cohort must enroll additional participants, all of whom will follow the same study protocol. However, instead of reporting data at the end of this year, this group is now expected to post data in the first half of next year. Structure still expects the Phase 2b study will report data from the type 2 diabetes cohort by the end of 2023.
Speaking on a conference call, CEO Raymond Stevens said the failure to collect the weight information was the fault of the contact research organization (CRO) conducting the trial. The unnamed CRO has taken responsibility and will cover the additional expense. But given the delay, Structure decided to take a look at the Phase 1b study.
“When we unblinded the data, and we saw the efficacy, up to 4.9% placebo-corrected weight loss, we realized that was materially relevant and we needed to disclose that information,” Stevens said. “That was the logic behind the disclosure.”
On the heels of the data disclosure, Structure announced it is raising $300 million in a private placement of securities. The investor group, which includes institutional investors and mutual funds, will buy 21.6 million ordinary shares and 2.4 million newly designated non-voting shares for $12.49 apiece. Structure’s opening stock price on Friday was $65.09, a 73.7% increase from the biotech’s closing $37.47 stock price on Thursday.
Blai Coll, Structure’s vice president of clinical development, said GSBR-1290’s weigh loss results at four weeks are comparable to four-week data of other small molecules in development. The Structure drug’s formulation as a once-daily pill could set it apart from other oral competitors, but it still needs to catch up. Pfizer’s danuglipron, which is a small molecule that targets GLP-1, is being evaluated in obesity and type 2 diabetes in a Phase 2b study that has enrolled more than 1,400 participants. Danuglipron is dosed as four tablets taken twice daily, but Pfizer is also developing a once-daily modified release version of this drug.
Eli Lilly’s contender is a once-daily oral small molecule called orforglipron. According to results published earlier this month in the New England Journal of Medicine, the drug met goals of a 26-week Phase 2 study. In addition to showing efficacy, the drug also led to clinically significant weight loss in adults who are obese or overweight.
Structure develops drugs that hit elusive targets called G protein-coupled receptors, or GPCRs. The company uses computational techniques to discover small molecules that hit receptors, such as GLP-1, that are currently addressed by large molecule biologics. Structure is one of the few biotech companies to go public this year, completing its $185 million IPO in February. Speaking during the Friday conference call, CFO Jun Yoo said the company knew it would need to eventually raise capital and the private placement offered a way to do it in the short term. The $300 million securities transaction extends Structure’s cash runway through the end of 2026 as the company looks ahead to pivotal clinical trials, he said.
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