The Rising Global Demand for GLP-1 Therapies
As global rates of diabetes and obesity continue to climb, GLP-1 receptor agonists (GLP-1 RAs) have attracted tremendous attention for their remarkable glucose-lowering and weight-reducing effects. However, all currently approved GLP-1 RAs-such as semaglutide and tirzepatide-are peptide-based drugs, predominantly administered by injection. Even the few available oral formulations have low bioavailability and require strict dietary restrictions during treatment, leading to poor patient compliance. Consequently, developing oral small-molecule GLP-1 receptor agonists has become a key goal to better meet clinical needs.
The Billion-Dollar Race for Oral GLP-1 Drugs
Major pharmaceutical companies around the world have already joined this fierce R&D race for oral GLP-1 drugs, each seeking a share of the multi-billion-dollar diabetes and obesity treatment market. Currently, two structural archetypes dominate the field—Eli Lilly’s Orforglipron and Pfizer’s Danuglipron—which serve as reference molecules for many fast-followers.
Recent clinical results have reshaped the competitive landscape. Eli Lilly’s Orforglipron demonstrated both safety and efficacy in Phase 3 trials, while Pfizer’s Danuglipron development was halted due to gastrointestinal side effects and drug-induced liver injury. These contrasting outcomes have left followers divided—some encouraged, others concerned.
Structural Innovation in Small-Molecule GLP-1 Agonists
Due to its complex molecular structure and synthetic challenges, few companies chose to follow Orforglipron early on. Yet its Phase 3 success now validates their strategic bet. Although no publications have disclosed the design rationale behind Orforglipron, structural analysis suggests it may have originated from peptide-to-small-molecule optimization, though this remains unconfirmed.
For companies developing “me-too” or “follow-on” compounds, the key lies in novel structural design that circumvents existing patents. If a new molecule demonstrates clear advantages in efficacy, pharmacokinetics, safety, or physicochemical properties, it justifies further development.
Gasherbrum Biotech opened the pyrazole ring of Orforglipron and introduced diethylphosphoryl and methylamino groups while removing two methyl groups from the tetrahydropyran ring, yielding Aleniglipron. The introduced phosphoryl oxygen and methylamino nitrogen likely form an intramolecular hydrogen bond, mimicking the cyclic structure while bypassing Orforglipron’s patent, which notably omits phosphorus-based substituents.
Chengyi Pharma and Ascletis Pharma employed heterocycle-replacement strategies, substituting Orforglipron’s indole core with indolizine and 4-azaindole, respectively. They also replaced different methyl groups with cyclopropyl units, producing ECC5004 (global rights licensed to AstraZeneca) and ASC30 (tentatively identified). While this “simple heterocycle swap” approach faces low feasibility due to broad patent coverage, minor gaps—such as Orforglipron’s limited protection of only indole and 7-azaindole cores—offer potential opportunities.
Hansoh Pharma adopted a ring-fusion design, linking substituents on Orforglipron’s benzopyrazole ring to construct a tricyclic structure, combined with N-methyl deuteration to yield HS10535 (tentatively identified; global rights licensed to Merck). This novel tricyclic scaffold likely provides strong patentability but presents synthetic challenges.
Improving Pharmacokinetics and Bioavailability
Beyond structural diversification, researchers also focus on modifying metabolically labile methyl groups through removal, cyclopropyl substitution, or deuterium modification, aiming to improve oral bioavailability and pharmacokinetic stability. For reference, Orforglipron exhibits 33-43% oral bioavailability in rats and 21-28% in cynomolgus monkeys, suggesting room for improvement. Currently, all four candidates-Orforglipron, Aleniglipron, ECC5004, and HS10535-have advanced into preclinical or clinical stages, marking exciting progress in the pursuit of next-generation oral GLP-1 receptor agonists.
Danuglipron – The Rise and Fall of Pfizer’s Small-Molecule GLP-1 Agonist
From Discovery to Clinical Setback
Danuglipron, developed by Pfizer, represents another major category of oral small-molecule GLP-1 receptor agonists. The compound originated from a high-throughput screening program, through which researchers identified a promising lead molecule. Multiple rounds of structural optimization eventually yielded Danuglipron as the final clinical candidate.
Danuglipron features a simple and modifiable structure, which—combined with early clinical data confirming its glucose-lowering and weight-loss efficacy—made it a prime fast-follow target for both domestic and international pharmaceutical companies. However, its development was later terminated due to drug-induced liver injury (DILI) and gastrointestinal adverse events, raising doubts among followers about whether they can successfully advance their own versions of the drug.
Patent Challenges and Strategic Innovation
In drug design, there’s no patent barrier that cannot be overcome, provided the strategy is bold and creative. This mindset remains the strongest driving force for Danuglipron’s followers. Yet, the challenge lies in achieving the smallest structural modifications to circumvent existing patents while still showcasing meaningful differentiation—a delicate balance that requires deep strategic and chemical insight.
Danuglipron’s core patent, filed in 2017, covers a relatively narrow chemical space, leaving room for innovative followers to explore. Several companies have already developed novel analogs using diverse structural strategies:
- VCT220 (Wentai Pharma): obtained by relocating the ether linkage, offering subtle yet patent-breaking structural variation.
- HRS-7535 (Hengrui Pharma): created via a cyclization strategy to form a new ring system.
- RGT-0112 (Qilu Ruige): designed by introducing a double bond into the piperidine ring, potentially enhancing rigidity and receptor binding.
- HDM1002 (Huadong Medicine): employs a unique oxetane (oxacyclobutane) substituent, introducing polarity and metabolic stability advantages.
- MDR-001 (Deruizhi Pharma): incorporates an ether linkage between two bicyclic moieties, forming a novel molecular scaffold.
- SAL-0112 (Shenzhen Salubris): adds a benzyl methyl substituent on the aromatic ring, subtly modifying lipophilicity and pharmacokinetics.
- ID-110521156 (Nitto Denko Corp.), XW-014 (Xianweida), and THDBH110 (Dongbao Zixing): each utilize simple heterocyclic replacements to differentiate from Pfizer’s parent compound.
In their quest to overcome the patent barriers of Orforglipron and Danuglipron, pharmaceutical companies around the world have showcased exceptional creativity and technical prowess. A variety of advanced medicinal chemistry strategies—including ring-opening and ring-closing transformations, scaffold hopping, functional group replacement, metabolic site blocking, and deuterium modification—have been employed to construct novel molecular architectures with independent intellectual property rights.
These innovations not only expand the structural diversity of GLP-1 receptor agonists, but also enrich the drug discovery toolbox, driving the continuous evolution of this therapeutic class. Collectively, these efforts are paving the way for the next generation of GLP-1-based therapies that aim to deliver improved safety, efficacy, and patient convenience.
Overcoming the Biggest Challenge – Drug-Induced Liver Injury (DILI)
Despite tremendous progress, drug-induced liver injury (DILI) remains the greatest obstacle in the development of GLP-1 receptor agonists. Whether peptide-based or small-molecule in nature, cases of liver toxicity have repeatedly emerged across clinical studies.
For chronic conditions like obesity and type 2 diabetes, which require long-term treatment, the presence of hepatic or renal toxicity is often clinically unacceptable. Thus, ensuring drug safety has become an enduring challenge—and a central research focus—in the GLP-1 field.
Looking ahead, the key question for scientists and developers alike is clear: How can intelligent drug design eliminate or mitigate hepatotoxicity while maintaining or enhancing therapeutic efficacy? The answer will define the future direction of GLP-1 receptor agonist innovation and determine which companies ultimately lead in this rapidly expanding market.
| Catalog | Name | Cas |
| B0005-464998 | Glycyrrhizic acid | 1405-86-3 |
| B0084-007194 | Semaglutide sodium salt | |
| B0084-043091 | Albiglutide | 782500-75-8 |
| B1370-076640 | Retatrutide | 2381089-83-2 |
| B2693-081366 | GLP-1(7-37) | 106612-94-6 |
| B0084-090106 | Lixisenatide | 320367-13-3 |
| B0084-474685 | Liraglutide | 204656-20-2 |
| B1370-474907 | Exenatide acetate | 914454-01-6 |
| B1370-341972 | Tirzepatide | 2023788-19-2 |
| B2693-357635 | Cotadutide | 1686108-82-6 |
| B2693-358569 | GLP-1(7-36) amide | 107444-51-9 |
| B2693-381544 | Glucagon-like peptide 1 (1-37), human | 87805-34-3 |
| B1370-426308 | Orforglipron | 2212020-52-3 |
| B1370-427890 | Oxyntomodulin TFA | |
| B1370-427891 | GLP-1 TFA | |
| B1370-449766 | Mazdutide acetate |