Karuna Therapeutics Inc. (NASDAQ: NASDAQ: KRTX ) is on the cusp of becoming a wholly owned subsidiary of Bristol-Myers Squibb (NYSE: NYSE: BMY ), as a key regulatory hurdle has been cleared. The waiting period under the Hart-Scott-Rodino Antitrust Improvement Act of 1976 (HSR Act), which is a requirement for the merger to proceed, expired on Tuesday night, signaling a green light from antitrust authorities.