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With PN-477, Protagonist is directly going up against Eli Lilly, which is advancing retatrutide, also a triple-G agonist, in a Phase II trial.
Despite coming late to the obesity party, Protagonist Therapeutics is looking to stand out in an increasingly competitive space by
offering
a novel “triple-G” agonist with a flexible dosing profile.
The California-based biotech on Monday nominated PN-477, a triple agonist of the GLP-1, GIP and glucagon receptors, for treating obesity. PN-477 is being developed as a daily oral treatment but comes with the option of being administered as a once-weekly subcutaneous injection. Protagonist expects to launch first-in-human Phase I studies for PN-477 in the second quarter of 2026.
Writing to investors on Monday evening, analysts at BMO Capital Markets called this dosing flexibility “interesting,” noting that the asset underscores Protagonist’s pro a differentiated developer of peptide therapies. “This is not another me-too GLP-1 mono-agonist and could present as an interesting opportunity for a strategic acquirer or partner,” the analysts wrote.
Still, PN-477 remains a very immature candidate, with only preclinical data to back it up. Protagonist on Monday announced that based on
in vitro
data, PN-477 has demonstrated the ability to activate all three of its target receptors. Animal model studies, including those in mice with diet-induced obesity, also provided early proof-of-concept for the candidate.
These early findings, according to Protagonist, indicate that PN-477 has the “right balance of potency, oral and in-vivo stability, and pharmacokinetic properties,” according to its Monday announcement.
In this regard, however, analysts took a wait-and-see approach. “Protagonist is unlikely to get any meaningful credit for the asset given the stage of development,” BMO wrote.
Analysts at Truist Securities agreed in a note to investors on Monday, conceding that the preclinical findings underscore PN-477’s “potential to be differentiated on weight loss,” however qualifying that the asset “needs clinical validation.” As in the case of BMO, Truist likewise sees PN-477 as “validation” of Protagonist’s oral peptide approach, which “is likely to be attractive to a potential partner.”
With PN-477, Protagonist is directly going up against Eli Lilly, which is advancing retatrutide, also a triple-G agonist. Phase II data in June 2023 showed that retatrutide could elicit
up to 24% weight loss
at 48 weeks. Lilly has since pushed retatrutide into
late-stage development
.
Meanwhile, fellow obesity leader Novo Nordisk has also hopped on the triple-G train,
partnering
with Chinese biotech United Laboratories in March for the subcutaneous drug UBT251, which is currently in early-stage studies for obesity and type 2 diabetes. Novo paid $200 million upfront and promised up to $1.8 billion in milestones.