A phase IIb clinical study has Frequency Therapeutics Inc. reeling and making big changes, including layoffs. The placebo-controlled phase IIb study of FX-322 in treating acquired sensorineural hearing loss by regenerating hair cells in the cochlea missed its primary efficacy endpoint, so the company is discontinuing the program. It’s also shutting down a phase Ib study of FX-345, a program for treating the same indication.