[Edaily Reporter KIM SAE-MI ] Peptron, Inc.(087010)Although the patent for a long-acting glucagon-like peptide-1 (GLP-1) formulation recently granted to includes a 1- to 3-month dosing cycle, analysts note that the company has not secured exclusive rights to a “once-monthly GLP-1” formulation. Critics point out that since the anti-obesity efficacy trials were conducted only up to once every two weeks at most, there are limitations to using them as evidence to support a 1- to 3-month dosing interval.

Prior Patent for “Once-Monthly GLP-1” Exists… Not Comprehensive Exclusive Rights

According to patent examination data from the Korean Intellectual Property Office on the 8th, Peptron, Inc. received a patent grant on the 23rd of last month for “Sustained-release microparticles containing a GLP-1 receptor agonist or a pharmaceutically acceptable salt thereof, and uses thereof.”

On the 1st, Peptron, Inc. announced that this patent would strengthen the intellectual property foundation for its once-monthly semaglutide formulation “PT403” and its long-acting terzepatide formulation “PT404.” Claim 3 specifies semaglutide or terzepatide as the GLP-1 receptor agonist. Claim 9 also specifies that the sustained-release microparticles are administered at intervals of 1 to 3 months.

However, a review of the examination history reveals that the “once-monthly” dosing schedule was not recognized as a new claim in this patent.

Last February, the examiner cited #G2GBIO, Inc.’s KR10-2375262 as prior art and issued a notice of rejection, stating that all of Peptron, Inc.’s claims 1 through 14 lacked inventive step. In particular, regarding claims 8 through 10, the examiner noted that the prior art already described that semaglutide PLGA microparticles are sustained-release for 5 weeks or more, up to a maximum of 6 months, and that the administration frequency could range from “once a month to once a quarter.” The office also determined that the drug release rates at the 1- to 2-week time points claimed by Peptron, Inc., were merely experimental confirmations of characteristics inherent in the prior art.

A patent attorney in the biotech field stated, “This patent is not one that Peptron, Inc. was the first to discover and register, demonstrating that semaglutide can be administered once a month,” adding, “While the phrase ‘While the phrase ‘patent for once-monthly semaglutide’ itself cannot be said to be incorrect, if it is interpreted as securing comprehensive exclusive rights to once-monthly semaglutide, there is a discrepancy with the actual scope of the rights,” he explained. He went on to emphasize, “It is clear that (this patent) does not secure exclusive rights to once-monthly semaglutide itself.”

Peptron, Inc. also maintains that the significance of this patent lies in the specific formulation design rather than the dosing schedule itself. A Peptron, Inc. official explained, “This patent reflects the polymer characteristics of the technology we are currently using or plan to use in the future,” adding, “We place greater significance on securing patent rights for the combination of the drug and the polymer, as well as the specific formulation design, rather than simply on the monthly dosing schedule itself.”

The rationale for overcoming the patent rejection was a specific PLGA combination… “Low-viscosity 1 + High-viscosity 2”

Peptron, Inc. chose to demonstrate the inventive step by highlighting a specific PLGA (poly(lactide-co-glycolide)) combination. In responding to the Korean Intellectual Property Office’s rejection grounds last June, the company emphasized that the differentiating factor lies not in “how long it lasts” but in “how the PLGA is combined.”

PLGA is a biodegradable polymer that encapsulates drugs to enable their gradual release within the body. The core claim of Peptron, Inc.’s patent specifies a method involving the inclusion of 3–12% by weight of a GLP-1 class drug, mixed with one type of low-viscosity PLGA and two or more types of high-viscosity PLGA.

In its written opinion, Peptron, Inc. argued that while G2GBIO, Inc.’s prior patent also allows for the mixing of multiple types of PLGA, it did not specify the exact combination of “one low-viscosity type plus two or more high-viscosity types.” It also emphasized that adding the low-viscosity PLGA to the two high-viscosity PLGA types simultaneously reduced both the phenomenon of the drug being released all at once and release delays, thereby increasing bioavailability.

What is notable is that Peptron, Inc. secured the patent decision without significantly narrowing the scope of its core claims through these arguments. The most important Claim 1 was maintained as is, and Claim 3—which specifies semaglutide and terzepatide—as well as Claim 9, covering a 1- to 3-month dosing cycle, also survived. In fact, the only part that was actually amended was Claim 4, which more clearly defined the PLGA combination.

Since the final patent decision document does not separately state the grounds for granting the patent, it cannot be conclusively determined that specific arguments were directly accepted. Rather, the patent decision was issued after Peptron, Inc. demonstrated that this PLGA combination and its release effects constituted the core basis for inventive step.

Hopes for a once-monthly long-acting formulation… but efficacy verified only up to two weeks?

Some analysts suggest that competitors have considerable leeway to circumvent Peptron, Inc.’s patent. The core of Peptron, Inc.’s patent lies in a specific combination:

“one type of

low-viscosity PLGA plus two or more types of high-viscosity PLGA.”

Therefore, if competitors design their formulations by using only one type of high-viscosity PLGA, altering the viscosity range of the PLGA, or replacing some of the polymers with different materials, they may fall outside the scope of Peptron, Inc.’s patent. In other words, simply being a once-monthly semaglutide product does not automatically constitute infringement of Peptron, Inc.’s patent.

A patent attorney commented, “Even for a once-monthly semaglutide product, if it does not use the combination of ‘one type of low-viscosity PLGA and two or more types of high-viscosity PLGA,’ it may not fall under this patent,” adding, “For example, it appears to be a patent with relatively significant room for design-around—such as by using only one type of high-viscosity PLGA or substituting the polymers with other materials.”

During the patent examination process, Peptron, Inc. repeatedly emphasized that the combination of “one type of low-viscosity PLGA and two or more types of high-viscosity PLGA” was the key distinction from prior art. Consequently, analysts suggest that if Peptron, Inc. attempts to broadly claim that other PLGA combinations used by competitors fall within the scope of its patent in the future, the explanations it provided during the examination process could actually work against it.

Furthermore, the fact that the patent has been granted does not mean the product can be commercialized without any restrictions. A patent attorney pointed out, “Whether a patent can be granted and whether it infringes on another company’s patent are separate issues,” adding, “Even a product that directly applies one’s own patent may infringe on another company’s prior patent, so a separate freedom-to-operate (FTO) review is necessary before actual commercialization.”

Regarding the possibility of competitors circumventing the patent, Peptron, Inc. official countered, “While it is possible to design an alternative formulation by varying the type or combination of polymers,” but noted, “The possibility of patent circumvention and the feasibility of securing an alternative formulation suitable for actual product development are separate issues that require separate review.” The official further elaborated, “It is difficult to assess the protective effect of this patent as limited based solely on the fact that alternative designs are possible.”

There are also concerns that Peptron, Inc. lacks sufficient data to support its long-acting therapy technology—administered at least once a month—which the company has emphasized. Critics argue that the scope of experiments supporting the 1- to 3-month dosing intervals also needs to be examined.

Peptron, Inc. administered a sustained-release semaglutide formulation to diet-induced obese (DIO) mice once every three days (Q3D), once a week (QW), and once every two weeks (Q2W). Although significant weight loss was observed in all three treatment groups, there were no test groups in which the anti-obesity efficacy was directly evaluated at a frequency of once a month or at intervals of 2–3 months. The patent specification also states that “significant weight loss effects were confirmed even with administration as infrequently as once every two weeks.”

In mini-pigs, blood concentrations were monitored for up to 70 days following a single subcutaneous administration of the semaglutide formulation to confirm the potential for long-term release. However, this was a study examining pharmacokinetics (PK) following a single dose, which differs from an efficacy study that directly verifies whether weight loss effects and safety are maintained with repeated administration once a month or at intervals of 2–3 months.

A patent attorney stated, “While there is some room to argue that there is evidence supporting a one-month dosing interval, it is difficult to say there is sufficient experimental evidence for intervals of two to three months,” adding, “Although this aspect was not raised as a separate ground for rejection during this review, there is a possibility it could become a point of contention in future invalidation proceedings.”

Peptron, Inc. also did not disclose whether it possesses additional data to prove the efficacy and safety of monthly administration or administration cycles of 2–3 months. A Peptron, Inc. official said, “Whether we possess additional data and the details thereof constitute confidential information related to our R&D status and development strategy,” adding, “It is difficult for us to comment further beyond the data currently disclosed.” The spokesperson added, “The data disclosed to date does not represent the entirety of the R&D information we possess.”