Ritter Pharmaceuticals Inc., developer of drugs to treat lactose intolerance, debuted on the Nasdaq today under the symbol RTTR.

The Century City pharmaceutical firm priced its initial public offering at $5 a share, half its previous target of $10 to $12 a share, according to regulatory filings. It expected to raise $20 million before underwriting expenses from the offering.

Ritter is developing therapies for the human gut that treat gastrointestinal diseases. The company intended to use the offering proceeds to support operations, create a public market for its common stock and gain future access to public equity markets, according to regulatory filings.