** Drug developer Jasper Therapeutics' shares fall ~50% to $8.65

** JSPR says its skin disease drug, briquilimab, met the main goal in the early-stage trial for treating chronic spontaneous urticaria (CSU)

** CSU is a skin condition where red, itchy bumps come and go without a clear reason

** Brokerage William Blair says patients treated with the 180 milligram dose every 8 weeks showed a weaker reduction in disease activity compared with other dose levels

** Brokerage says adverse events are not broken out by dose level, making it difficult to assess the safety profile of specific regimens

** Brokerage says 240 mg and 120 mg doses show strong initial efficacy but lose effectiveness over time, raising concerns about durability and long-term disease control

** All 11 brokerages rate the stock "buy" or higher; their median PT is $69 - LSEG

** JSPR gained 13.6% in 2024

(Reporting by Kamal Choudhury in Bengaluru)

((Kamal.Choudhury@thomsonreuters.com;))