Shares of Climb Bio Inc. fell 7% to $14.00 in pre-market trading on Thursday, extending a pullback after the biotech firm released Phase 1 clinical data for its experimental anti-APRIL monoclonal antibody, CLYM116.
The company’s stock remains well above its 52-week low of $1.54 but has retraced from its 52-week high of $18.33, reflecting broader investor caution following the data release. Climb Bio disclosed the results via an 8-K filing and a press release early in the session, detailing outcomes from a single 320 mg subcutaneous dose of CLYM116.
According to the announcement, the treatment achieved near-complete suppression of the APRIL protein and sustained 60–75% reductions in IgA and Gd-IgA1 levels over a 12-week period, with no serious adverse events reported. Climb Bio characterized the findings as demonstrating a "best-in-class APRIL suppression profile."
The company had pre-announced a September 3 R&D Spotlight Webcast in its August quarterly report, positioning the data release as a key milestone. However, investors appeared to adopt a "buy the rumor, sell the news" approach, with analysts noting that the market had weeks to position ahead of the readout. The positive Phase 1 results did little to offset near-term profit-taking, particularly as Phase 2 data from the ongoing NAVIGATE-2 trial in IgA nephropathy is not expected until the first half of 2027.
The broader U.S. equity market showed mixed performance during the session, with the S&P 500 up 0.3%, the Dow Jones Industrial Average gaining 0.6%, and the Nasdaq Composite adding 0.1%.
Wall Street coverage remains constructive, with Truist, Guggenheim, Oppenheimer, and RBC Capital maintaining "Buy" ratings on Climb Bio. The stock’s technical profile also came under pressure in early August, when a double-top sell signal was flagged.
Climb Bio’s shares have retraced from their 52-week high but remain significantly above their low, underscoring both the volatility and the long-term interest in its pipeline despite near-term profit-taking.
