** Brokerage Oppenheimer says that despite BridgeBio's BBIO.O heart disease drug seeing rapid early uptake, there remains preference for competitors like Alnylam's ALNY.O Amvuttra and Pfizer's PFE.N Vyndamax

** Vyndamax remains the mainstay treatment, according to brokerage's survey

** Entry of Amvuttra may slow growth of BridgeBio's Attruby, as doctors' interest in Alnylam's drug is high

** Brokerage adds that despite the apparent preference diagnosis rates and drug access should be improved with competition, although analysts estimates look very low for near-term Attruby sales

** Analysts expect 2025 sales of $162.43 million for Attruby, according to 3 analysts as per LSEG data

** The drugs are approved for ATTR-CM, a condition where faulty transthyretin proteins accumulate in the heart, potentially causing the organ to fail

** Brokerage also sees substantial concern over the durability of sales, particularly with anticipated generic entry in 2029

** Adds that Alnylam's decision to maintain premium pricing may sway insurers to other drugs, while Attruby's lower price appears to lack strategic value for BBIO

** Up to last close, PFE down 3.7%, ALNY up 19.4% and BBIO down 33.9% YTD

(Reporting by Padmanabhan Ananthan)

((Padmanabhan.Ananthan@thomsonreuters.com;))