Researchers and drugmakers spent decades chasing RNA interference as a method to “silence” harmful genes and thereby treat disease. But it took many years to refine the delivery of RNAi-based drugs.

One of the most well-known RNAi developers, Alnylam Pharmaceuticals, has found repeat success in delivering its medicines into the liver, winning U.S. approvals of four rare disease treatments.

Now, biotechnology startups are following in the footsteps of Alnylam and others like Ionis Pharmaceuticals, Arrowhead Pharmaceuticals and Dicerna Pharmaceuticals, which also develop different flavors of RNA-based drugs. Increasingly, drugmakers are looking at diseases outside the liver, such as those affecting the brain and spinal cord, believing the technology could help change how nervous system disorders are treated. Alnylam, for instance, is expecting to soon have early study data on an experimental RNAi treatment for Alzheimer’s disease.

Switch plans to develop small interfering RNA structures that could attach to a sensor and target specific cells. The company is named for its goal of developing cell-specific drugs.

“We’ve invented a way to put a simple and compact sensor on each siRNA molecule in the cells,” Datta said. “When the sensor actually detects an RNA biomarker, it will switch on the drug activity.”

Switch claims its technology can develop molecules that would deliver medicines efficiently into a cell while maintaining longer-lasting “knock down” of a target gene.

Datta declined to share which CNS diseases Switch is pursuing. The company is also exploring possible partnerships with other pharmaceutical firms.

“We are very well-positioned to build on progress that has been made in the field to create the next generation of RNAi medicine,” Datta said.

Its investor syndicate was led by Insight Partners and UCB Ventures, with participation from Eli Lilly, Upfront Ventures and Ono Venture Investment, among others.