Structure Therapeutics Inc. (NASDAQ: GPCR) is steadily advancing the clinical development of aleniglipron, an oral small molecule targeting obesity. Although the company is still several months away from filing for regulatory approval, it is already preparing for a significant issue that has historically affected the obesity treatment landscape: the proliferation of compounded, unapproved drug versions.
Aleniglipron is chemically similar to Eli Lilly & Co.'s (NYSE: LLY) orforglipron but has a shorter half-life, potentially differentiating it in the marketplace. The company has reported encouraging topline data from the ACCESS clinical program, which includes 36-week efficacy results from the core Phase 2b ACCESS study and the exploratory ACCESS II study, alongside preliminary data from the ongoing Body Composition and open-label extension studies.
Specifically, in the Phase 2b ACCESS study, participants receiving a 120 mg dose of aleniglipron experienced a statistically significant placebo-adjusted mean weight loss of 11.3% at 36 weeks. Across all active treatment arms, the rate of treatment discontinuation due to adverse events stood at 10.4%. Meanwhile, the exploratory ACCESS II study found that the 240 mg dosing yielded an even higher placebo-adjusted mean weight loss of up to 15.3% over the same period.
These results support the continued clinical advancement of aleniglipron as Structure Therapeutics has initiated three new studies to further characterize the drug’s efficacy and safety profile. These forthcoming data are intended to reinforce the competitive positioning of aleniglipron and contribute to the strategic design of the Phase 3 program.
Beyond aleniglipron, in December 2025, the company also launched a first-in-human Phase 1 trial for ACCG-2671, its lead oral small molecule amylin receptor agonist targeting obesity, signaling their broader commitment to developing novel oral therapies in this space.
Despite promising advancements, CEO Raymond Stevens recently voiced a growing apprehension about the market environment in an interview at the JPMorgan Healthcare Conference. He emphasized the increasing threat posed by compounded weight-loss medications, which are unapproved copies made by pharmacies rather than licensed pharmaceutical companies. Stevens described the unchecked growth of this "compounding issue" as his primary concern for the future of new obesity treatment entries.
Historically, patients turned to compounded formulations amid shortages of branded obesity drugs, seeking alternatives when demand overwhelmed supply. Even as supply constraints have largely diminished, compounded drugs remain a visible presence in the patient market, undermining the uptake of newly approved medications.
Industry executives echo similar concerns. Novo Nordisk A/S (NYSE: NVO) CEO Mike Doustdar recently estimated that as many as 1.5 million patients in the U.S. continue to utilize compounded weight-loss products, attracted largely by lower prices relative to branded treatments. This widespread use of compounded drugs poses risks to the adoption rates of novel therapies and could exert downward pressure on pricing across the obesity drug sector.
Stevens has suggested that Structure Therapeutics’ aleniglipron might enjoy some barriers against straightforward replication. As a small molecule, aleniglipron's manufacturing is more intricate compared to peptide-based injectable drugs like Lilly's Zepbound and Novo Nordisk's Wegovy, which are considered easier to duplicate. Nonetheless, this possible advantage does not eliminate the overarching industry challenge of compounded drug proliferation.
There is a consensus among several drugmakers that regulatory oversight has not sufficiently addressed this issue. They argue that the U.S. Food and Drug Administration (FDA) has fallen short in effectively curbing the ongoing production and distribution of compounded obesity medications, especially now that authorized drug shortages have eased.
On the market front, Structure Therapeutics shares experienced a slight decline of 0.80% to $83.65 during Thursday trading, as per Benzinga Pro data. Meanwhile, other major obesity drugmakers, including Eli Lilly and Novo Nordisk, faced price pressures with recent share decreases of 4.77% and 3.47%, respectively.
The growing spotlight on compounded obesity drug use highlights an emerging risk factor for the sector, potentially influencing patient access, pricing dynamics, and the commercial potential of innovative treatments. While companies like Structure Therapeutics are advancing promising oral small molecules, their success may depend in part on addressing the legal, regulatory, and market challenges posed by compounded competitors.