BOSTON — September 15, 2026
Syntis Bio, Inc. announced results from the 28-day multiple-ascending-dose (MAD) portion of its Phase 1/1b SYNTIETY-1 clinical trial evaluating oral SYNT-101 in adults with overweight or obesity. Across three dose cohorts ranging from 857 mg to 2,571 mg, SYNT-101 was well tolerated, with no treatment discontinuations or dose reductions and gastrointestinal adverse events occurring at rates comparable to placebo. Exploratory pharmacodynamic assessments also demonstrated a multi-hormonal satiety response, including 2- to 5-fold increases in GLP-1 and PYY and a reduction in ghrelin. Participants receiving SYNT-101 experienced greater weight loss than placebo-treated participants in each dose cohort. The findings build on the earlier single-ascending-dose results and provide a clinical foundation for the company’s plan to advance SYNT-101 into Phase 2 development in 2027..
SYNT-101 Modulates Multiple Satiety Hormones
SYNT-101 is designed to produce a localized metabolic response in the small intestine rather than relying on sustained systemic drug exposure. The once-daily oral tablet temporarily blocks nutrient absorption in the proximal small intestine and redirects nutrients toward the distal intestine, with the goal of stimulating endogenous secretion of GLP-1, PYY, GIP and ghrelin-related satiety signals. Syntis Bio is developing the approach to replicate aspects of the hormonal response associated with gastric bypass surgery while avoiding continuous systemic exposure characteristic of many existing obesity medicines. The MAD study’s exploratory findings showed concordant changes in multiple metabolic hormones, which the company said were consistent with patterns observed after gastric bypass. The mechanism could offer a differentiated approach to weight management, although the current results remain early-stage clinical findings and require confirmation in larger, controlled studies.
28-Day Data Support Favorable Tolerability Profile
The 28-day MAD results provide an important safety and tolerability milestone for SYNT-101, particularly as gastrointestinal adverse events are a common consideration in obesity treatment. The randomized, double-blind, placebo-controlled study included 23 adult participants across three ascending-dose cohorts, with all evaluated dose levels showing no discontinuations and no dose reductions. GI adverse events occurred at similar rates among SYNT-101 and placebo recipients. The company also reported greater weight loss among SYNT-101-treated participants in each dose cohort compared with placebo, with the observed reductions described as comparable to weight loss reported with GLP-1 therapies over a similar treatment period. Syntis Bio plans to present detailed findings in a late-breaking presentation at ObesityWeek 2026 in Washington, D.C., scheduled for November 14–17, providing an opportunity for the broader scientific community to review the emerging clinical dataset.
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Syntis Bio Prepares SYNT-101 for Phase 2
Syntis Bio plans to initiate a Phase 2 study of SYNT-101 in 2027, positioning the program as the lead clinical application of its SYNT™ synthetic tissue-lining technology. The platform uses mussel-inspired polymer chemistry to create a temporary polydopamine lining in the duodenum, designed to remain for up to 24 hours before being naturally cleared. Beyond nutrient exclusion, the company believes the technology could enable gut-restricted enzymes and improve oral drug bioavailability. Syntis Bio is also developing programs in rare metabolic diseases, expanding the potential applications of its small-intestine-focused platform. With favorable 28-day tolerability, early weight-loss signals and multi-hormonal satiety modulation, SYNT-101 has reached an important development milestone as Syntis Bio prepares for Phase 2 testing and further evaluation of its differentiated oral approach to obesity.
Source: Syntis Bio press release
