Officials at Sigilon Therapeutics Inc. declined to comment beyond a press release on the FDA’s clinical hold for the phase I/II study with encapsulated cell therapy SIG-001 for severe or moderately severe hemophilia A. Shares of Cambridge, Mass.-based Sigilon (NASDAQ:SGTX) closed at $6.90 on July 9, down $2.34, or 25% after Wall Street learned of the regulatory move, which came because one of three patients treated has developed inhibitors to factor VIII (FVIII).