Corbus Pharma rises on US FDA's second 'fast-track' tag for cancer therapy

** Shares of drug developer Corbus Pharmaceuticals CRBP.O rise 6.6% to $10 premarket

** Company says U.S. FDA has granted a "fast-track" designation to its experimental therapy, CRB-701, for head and neck cancer that has returned or spread after earlier treatments

** FDA's "fast-track" tag aims to speed development and review of drugs for serious conditions with unmet medical need

** A "fast track" tag was granted to CRB-701 for the treatment of cervical cancer last year

** As of last close, shares down 20% YTD