** Biotech firm Beam Therapeutics' BEAM.O shares rise 9.7% to $31.24 premarket
** BEAM says its experimental gene-editing therapy, BEAM-302, surpassed theoretical threshold for efficacy with the third dose level of 60 mg of the therapy
** Three patients received the 60 mg dose in an early-stage study to treat Alpha-1 antitrypsin deficiency (AATD)
** AATD is a genetic disorder that occurs when the body doesn't produce enough of the AAT protein which protects lungs and liver
** There is a clear path forward for BEAM-302 - brokerage BMO Capital Markets
** Co plans to continue testing higher doses in the ongoing study, expects to report further data in H2 2025
** BEAM has fallen 23% in the past 12 months
(Reporting by Siddhi Mahatole)
((siddhi.mahatole@thomsonreuters.com))