Jasper Therapeutics’ anti-c-KIT antibody has shown promise in a Phase 1b/2a test in people with certain irritable skin conditions, sending its shares rising on Monday.
Fourteen out of 15 participants in the SPOTLIGHT study with cold urticaria or symptomatic dermographism who are refractory to antihistamines had a clinical response to briquilimab within the six-week preliminary analysis period, according to a Monday release.
Cold urticaria and symptomatic dermographism both lead to hives and swelling but are caused by different triggers. Cold urticaria is due to cold temperatures, while symptomatic dermographism is provoked by rubbing or scratching of the skin.
Jasper’s shares $JSPR rose by as much as 20% at market open Monday.
Out of 12 participants given a higher 120 mg dose of briquilimab, 10 had a complete response and the 11th patient had a partial response. “Overall, the data shows clear activity for briquilimab, with a rapid onset of action across both response rate and serum tryptase reductions,” William Blair analysts said.
But the complete responses only lasted around four weeks, with the number of responders dropping from 10 to six afterwards, the analysts added. In contrast, Celldex Therapeutics’ anti-KIT antibody, barzolvolimab, given at the 1.5 mg/kg dose produced responses that lasted through six weeks in a Phase 1b test in people with the same skin conditions.
However, almost half of those treated in Celldex’s study also had hair color changes. In SPOTLIGHT, Jasper said briquilimab was well-tolerated with no serious or grade 3 or higher adverse events observed. The company added that there were no skin color or hair color side effects.
The California biotech now has “regulatory clearance” to add a 180 mg dose cohort to the SPOTLIGHT study, with full results expected in the first half of next year.
Elsewhere, briquilimab is also being tested in the Phase 1b/2a BEACON trial in chronic spontaneous urticaria patients who still have symptoms despite treatment with Novartis and Genentech’s Xolair or can’t tolerate that treatment. Jasper said initial results from that study are expected in January.