Ritter's microbiome modulator fails lactose intolerance phase 3 

Stomach Pain
Ritter Pharmaceuticals ended June with $4.4 million in cash and equivalents, down from $7.8 million at the start of the year. (Pixabay)

A phase 3 trial of Ritter Pharmaceuticals’ lactose intolerance prospect RP-G28 has missed its primary endpoint. The oligosaccharide microbiome modulator was no better than placebo at reducing lactose intolerance symptoms, leaving Ritter considering whether to look for strategic alternatives. 

Ritter moved RP-G28 into the 557-subject phase 3 in the belief the drug could modulate bacteria in the large intestine to increase the metabolism of lactose. In doing so, Ritter anticipated reducing the severity of abdominal pain, cramping, bloating, gas and other symptoms associated with intolerance to the allergen.

That theory is now on the ropes. After 60 days, the phase 3 tracked a 3.159 reduction over baseline in the lactose intolerance symptoms of people who took RP-G28. However, the mean reduction in the placebo group, 3.420, was numerically bigger still, causing the trial to miss its primary endpoint.

Ritter saw a similar pattern across the secondary endpoints. A key secondary endpoint found 36.2% of people in the RP-G28 arm experienced a meaningful treatment benefit. The placebo was almost as efficacious, though, with 34.1% of people experiencing a meaningful benefit. Ritter said RP-G28 and placebo performed similarly across other secondary endpoints, too. 

The information shared by Ritter is almost entirely devoid of reasons for optimism about the future of RP-G28. Ritter is yet to give up on the asset, choosing instead to continue analyzing the data, but CEO Andrew Ritter acknowledged it may soon be time to look into “alternative strategic options for the company.”

Ritter may struggle to keep developing RP-G28 even if it wants to. The company ended June with $4.4 million in cash and equivalents, down from $7.8 million at the start of the year, giving it a fairly small financial runway. Ritter’s ability to extend the runway could be hindered by its standing with investors, who responded to the phase 3 failure by driving its stock down more than 70%, putting it deep into penny stock territory.