Attovia Therapeutics (NASDAQ:ATTO) reported 12-week results from a small phase 1b study of its experimental itch treatment ATTO-1310, saying a single dose produced sustained responses in patients with chronic pruritus of unknown origin and in those with high-itch atopic dermatitis.
The company plans to begin dosing patients in two larger phase 2 studies in the first half of 2027, with results expected in 2028. ATTO-1310 is a subcutaneous antibody designed to target IL-31, a protein involved in itch.
The phase 1b study enrolled patients with severe itch and tested two doses against placebo. Each cohort included 12 to 14 patients, randomized 2-to-1 to receive ATTO-1310 or placebo. Safety, drug exposure and immune responses were the primary endpoints; measures of clinical activity were exploratory.
Chronic itch results
Among patients with chronic pruritus of unknown origin, or CPUO, 14 of 17 who received ATTO-1310 achieved at least a four-point reduction on a 10-point itch scale at week 12, Chief Medical Officer Hubert Chen said. The placebo-adjusted difference was about 60 percentage points.
Eight of the 17 treated patients had an itch score below two at week 12, a level the company described as itch-free or nearly itch-free, compared with none on placebo. All patients in the chronic pruritus cohort met the diagnostic criteria for CPUO, Chen said.
Brian Kim, vice president and chief biotechnology officer at Northwell Health, said CPUO involves chronic itch with no clearly identified cause and has no FDA-approved treatments. He said the condition is particularly prevalent among older adults.
Atopic dermatitis and placebo response
In the high-itch atopic dermatitis group, approximately 45% to 50% of treated patients maintained a four-point itch response through weeks eight and 12, Chen said. However, four additional placebo patients became responders after week four, bringing the number of placebo responders to six out of eight.
Chen said three placebo patients used rescue medications after week four, compared with none of the 18 patients treated with ATTO-1310. He cautioned that the elevated placebo response could not be attributed to any single factor and that the small placebo group made the results sensitive to changes in a few patients.
On the more stringent itch-score threshold below two, five treated patients met the measure at week 12, compared with one placebo patient. Chen also reported improvements in skin lesions: 44% of treated patients achieved at least a 75% improvement on a standard eczema severity measure at week 12.
Jonathan Silverberg, a professor of dermatology at The George Washington University School of Medicine, said patients with severe itch but mild-to-moderate skin lesions can be undertreated because visible symptoms do not always reflect the burden of their disease.
Safety and development plans
Chen said ATTO-1310 was generally well tolerated in the patient cohorts. One serious event, a worsening of a preexisting hiatal hernia, was deemed unrelated to the study drug, and no adverse events led to discontinuation. No treated patients had a dermatitis adverse event, he said.
Attovia executives said the results and drug exposure data support testing quarterly maintenance dosing. They also suggested ATTO-1310 could differ from nemolizumab, which targets the IL-31 receptor, though the company acknowledged the limitations of comparisons across separate trials. Chen described biomarker findings supporting a potential biological difference as preliminary.
Attovia plans to enroll approximately 300 patients in its phase 2 CPUO study and 255 across two parts of its atopic dermatitis study. The latter trial will use measures intended to address placebo response, including larger treatment groups and an analysis that counts patients using rescue medication as nonresponders.
The company has also initiated a phase 1b study in cholestatic pruritus and expects data in the second half of 2027. CEO Tao Fu said Attovia’s cash runway funds its operating plan into 2030.
About Attovia Therapeutics (NASDAQ:ATTO)
Attovia Therapeutics, Inc (NASDAQ: ATTO) is a clinical-stage biopharmaceutical company focused on developing antibody-based medicines for immune-mediated and inflammatory diseases. The company is working to address conditions in which existing treatments may not provide adequate efficacy, durability, or convenience.
Attovia uses its proprietary antibody-engineering and drug-development capabilities to discover and advance biologic therapies designed to modulate disease-driving immune pathways.
