An experimental drug called sibofimloc did not prevent necrotizing enterocolitis, a serious intestinal disease, in premature piglets, according to a 2026 preprint study. All piglets fed formula with the drug developed the disease, compared with 0% of piglets fed donor human milk. Gram Research analysis suggests the drug is not yet ready for human infants.
Premature babies can develop necrotizing enterocolitis, a dangerous disease that inflames and damages the intestines. Researchers tested whether an experimental drug called sibofimloc could block certain harmful gut bacteria that may contribute to it. The study used premature piglets, which are often used to model human infant gut conditions. According to research reviewed by Gram, the drug did not prevent the disease. Every piglet fed formula with the drug developed it, while piglets fed donor human milk had no cases. The drug was absorbed into the bloodstream, but its levels dropped over the first week of life. The gut bacteria of drug-treated piglets also looked much like those of untreated piglets. The results suggest that targeting these bacteria alone may not be enough, and that other causes may need attention. This work was a preprint that has not yet been peer reviewed, so it should be viewed as early evidence.
Key Statistics
A 2026 bioRxiv preprint on premature piglets found that 100% of piglets fed formula with the experimental drug sibofimloc developed necrotizing enterocolitis, the same rate as untreated formula-fed piglets.
In the same 2026 piglet study, piglets fed donor human milk had 0% cases of necrotizing enterocolitis, while the drug-treated group showed significantly reduced intestinal crypt depth, a sign of impaired gut lining repair.
The 2026 study found that blood levels of sibofimloc in premature piglets decreased between postnatal day 2 and day 8, suggesting reduced drug absorption as the intestinal barrier matures.
The Quick Take
- What they studied: Researchers asked whether a drug that blocks a sticky protein used by certain gut bacteria could prevent a serious intestinal disease in premature infants, using premature piglets as a stand-in.
- Who participated: Premature piglets, which are commonly used in research because their digestive systems resemble those of human babies. The exact number of piglets was not specified in the available summary.
- Key finding: All piglets fed formula with the drug developed necrotizing enterocolitis, the same as untreated formula-fed piglets, while piglets fed donor human milk had 0% cases. The drug did not lower the risk of disease or its severity.
- What it means for you: This drug is not shown to protect against this disease, and it should not be considered a substitute for proven care. Parents and caregivers should continue to follow medical advice about feeding premature infants, including the benefits of donor human milk when available.
The Research Details
The researchers ran two experiments. First, they gave premature piglets increasing doses of the drug, at 10, 25, and 50 mg/kg twice a day, over 9 days. This step checked whether the drug was safe and how well the body absorbed it. The second experiment ran for 10 days and randomly assigned piglets to one of three groups: formula with the drug, formula alone, or donor human milk as a healthy comparison.
Random assignment means that chance, rather than the researchers’ choices, decided which piglets received which treatment. This helps prevent unfair differences between groups. The team then examined the piglets’ intestinal tissue under a microscope and sequenced the genetic material of the gut bacteria to see which microbes were present.
The researchers also measured how much of the drug stayed in the blood over time. This showed how the body handled the drug as the piglets’ intestines matured during the first week of life.
Using random assignment and a comparison group makes it possible to tell whether the drug itself made a difference. Testing in piglets also lets researchers study intestinal tissue and bacteria in detail, which would be hard to do safely in human infants. Because piglet digestive systems are similar to those of human babies, these results can guide decisions about whether human testing is worth pursuing.
This study is a preprint, which means it was posted online before independent experts in the field reviewed it. Preprints can be valuable for sharing early results quickly, but their conclusions can change after peer review. The sample size was not clearly stated in the available information, which makes it harder to judge how precise the results are. The study used animals, so results may not fully predict what would happen in human infants.
What the Results Show
The drug was absorbed into the bloodstream in a way that increased with the dose, meaning higher doses led to higher blood levels. However, blood levels dropped between day 2 and day 8 of life. The researchers suggest that as the intestinal barrier matures, less of the drug passes into the body.
The main outcome was disappointing. Piglets fed formula with the drug developed necrotizing enterocolitis at a rate of 100%, the same level seen in untreated formula-fed piglets. The drug also did not reduce how severe the disease became. In contrast, piglets fed donor human milk had 0% cases, which highlights how strongly human milk appears to protect against this condition in this model.
The drug-treated piglets also showed signs of more intestinal injury. Their intestinal crypts, which are small pits in the gut lining where new cells form, were significantly shallower. Shallower crypts suggest the lining had a reduced ability to repair itself.
The bacterial analysis showed that drug-treated piglets had gut bacteria that looked much like those of untreated formula-fed piglets. Clostridium perfringens was the dominant bacterium in these groups. This suggests that blocking the targeted bacteria did not change the overall gut community in a meaningful way.
The dose-escalation portion showed that the drug was tolerated and absorbed across the doses tested, which supports its general safety at these levels in piglets. The drop in blood levels over the first week suggests that dosing for very young infants may need special attention, since the drug’s behavior changes as the gut develops. The finding about reduced crypt depth is important because it points to possible harm to the intestinal lining, which the researchers believe may interfere with healing.
Necrotizing enterocolitis is linked in many studies to an increase in Enterobacteriaceae, a family of bacteria that includes E. coli. Researchers have hypothesized that FimH, a sticky protein these bacteria use to attach to the gut lining, may drive inflammation. This study tested that idea directly and found that blocking FimH was not enough to prevent the disease. The result suggests that the cause of necrotizing enterocolitis is more complicated than one bacterial attachment mechanism, and it agrees with the view that the condition involves many interacting microbes and factors.
This study was conducted in piglets, and while their digestive systems share features with human infants, they are not identical. The final sample size was not clearly stated in the available information, which limits how confidently the results can be interpreted. As a preprint, the study has not yet been checked by independent experts. The experiment ran for a short 10-day period, so it cannot show long-term effects. Testing only one dose for the efficacy study also means that other doses or timing strategies were not evaluated.
The Bottom Line
Research shows that sibofimloc did not prevent necrotizing enterocolitis in premature piglets, so it should not be considered a protective treatment based on this study. Confidence in this conclusion is moderate, because it comes from one animal study that has not yet been peer reviewed. Donor human milk was associated with 0% disease in this model, which supports existing guidance that human milk is an important part of feeding premature infants when it is available.
Clinicians, researchers, and families of premature infants should pay attention, since this study narrows down which treatment approaches are unlikely to work. Parents of premature babies should not seek this experimental drug, because it is not approved or proven for this use. People with no connection to premature infant care can treat this as an interesting research update rather than a practical change.
Experimental drugs usually need years of further animal and human testing before they could be considered for use. Even if future studies look promising, a realistic timeline for human testing would likely span several years. For now, there is no expected benefit for infants from this specific drug.
Frequently Asked Questions
Can the drug sibofimloc prevent necrotizing enterocolitis in premature babies?
Based on a 2026 preprint study in premature piglets, sibofimloc did not prevent necrotizing enterocolitis. All formula-fed piglets receiving the drug developed the disease, matching untreated controls. The study has not yet been peer reviewed, and human testing has not been reported.
Does donor human milk protect premature infants from necrotizing enterocolitis?
In a 2026 piglet study, piglets fed donor human milk had 0% necrotizing enterocolitis, compared with 100% in drug-treated formula-fed piglets. Animal results may not fully apply to humans, but the findings support the existing view that human milk plays a protective role in preterm feeding.
What causes necrotizing enterocolitis in premature babies?
Necrotizing enterocolitis is linked to an increase in certain gut bacteria, including Enterobacteriaceae, and to inflammation of the intestinal lining. Research suggests it involves multiple microbes and factors, so blocking one bacterial attachment mechanism may not be enough, as a recent piglet study found.
Is sibofimloc approved for use in infants?
Sibofimloc is an experimental drug that is not approved for preventing necrotizing enterocolitis in infants. The available research comes from animal studies, and it found no protective benefit. Parents should discuss any treatment questions with a neonatal or pediatric care team.
Want to Apply This Research?
- For users tracking feeding or digestive health, log daily feeding type (formula, breast milk, or donor milk), number of feedings, and any signs of digestive distress such as bloating, feeding intolerance, or changes in stool, using a simple 1 to 5 scale for severity.
- Encourage users who care for premature infants to keep a feeding and symptom log to share with their healthcare team, and to ask about donor human milk options during regular appointments. Users should not start or change any treatment based on this study without talking to a qualified clinician.
- Over the long term, track feeding patterns, weight changes, and any digestive symptoms weekly, and flag any sudden changes such as swollen abdomen, vomiting, or blood in stool for immediate medical attention. Review trends with a pediatrician or care provider, and update the log as new research on preterm infant nutrition becomes available.
This article summarizes a preprint study in premature piglets that has not yet been peer reviewed. The findings are not medical advice and do not establish that any treatment is safe or effective for human infants. Necrotizing enterocolitis is a serious condition that requires prompt care from a qualified medical team. Parents and caregivers should consult a pediatrician or neonatal specialist before making any decisions about infant feeding or treatment.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.