** Shares of Apogee Therapeutics APGE.O slide 11.4% to $73.34 premarket

** The drug developer says its experimental skin disease therapy met the main goal in results from part B of its mid-stage study

** Adds that 65.9% of patients treated with mid-dose zumilokibart showed significant improvement in their eczema

** Plans to move forward with the mid-dose for late-stage studies

** Brokerage Stifel says results "near identical" as prior part A data for the mid-dose

** "While pushing exposure vs. the prior study did not achieve differentiated outcomes, we ultimately don't think it matters and view the highly competitive efficacy/dosing profile as attractive at this valuation" - Stifel

** APGE was testing the treatment in patients with moderate-to-severe atopic dermatitis a chronic, inflammatory skin condition

** The firm also announces an up to $1.3 billion financing collaboration with Blackstone Life Sciences to advance late-stage development and commercialization of zumilokibart

** Up to last close, stock up 9.7% YTD