There's a large $2 billion market for over-the-counter products to treat the roughly 39 million Americans with lactose intolerance, but even with the available options, 82 percent of lactose-intolerant patients report they still experience symptoms.

"The primary means to treat lactose intolerance is to avoid dairy products," Andrew Ritter, president and CEO of Ritter Pharmaceuticals Inc., told BioWorld Insight. Ritter is the founder of the company that bears his name and also a sufferer of lactose intolerance since his early childhood.

There's a growing market for lactose-free products – soy milk for instance – but they're not ideal because avoiding dairy products increases health risks, including osteoporosis and hypertension.

Patients' other option is over-the-counter lactase supplements, but they can be inconvenient. "The problem with lactase supplements is that you have to carry them around and take them every time you want to eat dairy," Ritter said.

And even the most diligent patient can sometimes experience symptoms from foods they don't realize contain dairy products: hot dogs, breads, salad dressings, soups and pastas can all contain or be mixed with dairy products.

Despite the unmet need in a fairly large market, no prescription drugs have been developed to treat lactose intolerance. "It's been a hidden market where people have suffered by themselves," Ritter said. "If you have it, it's a serious issue, but if you don't have it, it isn't an issue at all."

A survey of lactose-intolerant patients revealed that 65 percent of patients would likely, or very likely fill a prescription for a drug to treat lactose intolerance if their doctors recommended it.

Ritter Pharma's solution is a prescription drug called RP-G28, an oligosaccharide designed to produce colonic adaption, a process that changes the microbiota in the large intestine.

Lactose is normally broken down in the small intestine into individual sugars: glucose and galactose. Patients with lactose intolerance lack the enzyme, lactase, responsible for breaking down the disaccharide, so lactose travels into the large intestine, where it's fermented by bacteria, generating gases that produce embarrassing and painful side effects. RP-G28 stimulates the number and function of endogenous bifidobacteria and lactobacilli that are capable of metabolizing lactose rather than fermenting it.

In a 62-patient Phase II trial, 30 days after a 35-day treatment cycle, six times as many patients treated with RP-G28 reported the ability to consume dairy products without symptoms compared to those that received placebo. Patients taking RP-G28 also had statistically significant relief in abdominal pain, with a "p" value of 0.03. Complete results from the Phase II trial will be published in a peer-reviewed journal.

Ritter Pharma is proceeding with plans to run a Phase IIb trial, while "in discussion with various interested parties" to potentially fund future development, Ritter said. Future trials will explore the durability of the effect to see how often retreatment is required.

There's also potential for RP-G28 to be used to encourage the colonization of good bacteria to treat other major digestive diseases, including Crohn's disease, irritable bowel syndrome, inflammatory bowel disease and ulcerative colitis.