Results build on preliminary Week 4 findings, in which a single dose of ATTO-1310 demonstrated rapid, deep, and durable itch relief in patients with chronic pruritus (CP) and high-itch atopic dermatitis (AD)

The single dose also delivered skin lesion improvements that deepened through Week 12 in patients with high-itch AD

Approximately 95% suppression of IL-31 through Week 12 supports potential for quarterly dosing

Initiation of global Phase 2 trials of ATTO-1310 in patients with chronic pruritus of unknown origin (CPUO) and high-itch AD expected in 1H 2027

Company to host virtual KOL and clinical development update call today, November 5, 2026, at 4:30 pm ET

SAN CARLOS, Calif., Nov. 05, 2026 (GLOBE NEWSWIRE) -- Attovia Therapeutics, Inc. (“Attovia” or the “Company”) (Nasdaq: ATTO), a clinical-stage biopharmaceutical company developing next-generation biotherapeutics for immune-mediated diseases with high unmet need, today announced positive topline 12-week results from its Phase 1b study of ATTO-1310, a next-generation anti-IL-31 ATTOBODY-based precision itch therapy, in patients with chronic pruritus and high-itch atopic dermatitis.

“These results exceeded our expectations, building on the compelling Week 4 findings and providing strong emerging evidence supporting the key pillars of our differentiated target product profile: rapid, deep, and durable itch relief, the potential for quarterly dosing, and a favorable safety profile,” said Tao Fu, Founder and Chief Executive Officer of Attovia. “We are particularly encouraged by the remarkable depth and durability of itch relief observed in patients with CP, as well as the sustained improvements in both itch and skin lesions in patients with high-itch AD—all following a single subcutaneous dose. Combined with sustained IL-31 suppression through Week 12, these findings further strengthen our confidence in ATTO-1310’s potential to become a next-generation IL-31 therapy for patients suffering from chronic itch conditions. We look forward to advancing ATTO-1310 into two Phase 2 trials in the first half of 2027.”

The Phase 1 randomized, double-blind, placebo-controlled, four-part study (NCT06787586) was conducted across 17 sites in the U.S. and Canada.

Favorable Tolerability
ATTO-1310 was generally well tolerated in both healthy volunteers (HV) and patients. In the HV portion of the study, there was one treatment-emergent adverse event (TEAE) that led to treatment discontinuation due to Grade 1 fever. There were no TEAEs that led to study discontinuations in CP and AD patients. There was one serious TEAE (worsening of a pre-existing hiatal hernia), which was deemed unrelated to study treatment.

ATTO-1310 demonstrated low immunogenicity. Anti-drug antibodies (ADAs) were detected in 7.8% of HV and patients, with no observed impact on pharmacokinetics, target engagement, tolerability, or clinical activity.

Pharmacology Supports Potential Quarterly Dosing
In both HV and patient cohorts, a single subcutaneous (SC) dose of ATTO-1310 led to rapid, sustained suppression of circulating IL-31 (approximately 95%) through Week 12, and drug concentrations remained above the IC90 throughout this period. Together, these data support the potential for quarterly maintenance dosing of ATTO-1310.

Rapid Itch Relief Deepened and Sustained through Week 12 Following a Single Dose in Patients with CP
A rapid, clinically meaningful reduction in itch of ≥4 points on the Peak Pruritus Numerical Rating Scale (PP-NRS), referred to as PP-NRS4, was observed as early as Week 2, with 47% of ATTO-1310-treated patients achieving PP-NRS4 vs. 0% with placebo (p < 0.05), increasing to 82% vs. 22% with placebo (p < 0.01) at Week 12. A similar trend was observed in patients who were itch-free or nearly itch-free (PP-NRS<2), with 47% of ATTO-1310-treated patients achieving response at Week 12 vs. 0% with placebo (p < 0.05).

Patients with CP achieving at least a 4-point reduction from baseline (PP-NRS4):
% (n/N) of PP-NRS4 responders	Placebo (n=4)	4.5 mg/kg (n=8)	Placebo (n=5)	9 mg/kg (n=9)	Pooled placebo (n=9)	Pooled ATTO- 1310 (n=17)
Week 4	0% (0/4)	50% (4/8)	0% (0/5)	78%* (7/9)	0% (0/9)	65%** (11/17)
Week 12	25% (1/4)	75% (6/8)	20% (1/5)	89%* (8/9)	22% (2/9)	82%** (14/17)
p < 0.05; *p < 0.01; all p values are nominal.

Patients with CP achieving a worst itch score of less than 2, meaning they were itch-free or nearly itch-free status (PP-NRS<2):
% (n/N) of PP-NRS<2 responders	Pooled placebo (n=9)	Pooled ATTO-1310 (n=17)
Week 4	0% (0/9)	35% (6/17)
Week 12	0% (0/9)	47%* (8/17)
*p < 0.05; all p values are nominal.

“CPUO is one of the most common conditions I see in my clinic, yet despite affecting an estimated two to five million adults in the U.S., there are still no FDA-approved treatments,” said Brian Kim, MD, MTR, FAAD, Vice President and Chief Biotechnology Officer at Northwell Health, Inaugural Robin and Jack Ross Chair and Professor of Bioelectronic Medicine and Neuroimmunology at the Feinstein Institutes for Medical Research. “These patients, many of whom are older adults, suffer from relentless itch that profoundly impacts their quality of life and is often associated with anxiety and depression. ATTO-1310’s strategy of targeting the IL-31 ligand rather than its receptor offers a potentially differentiated approach to achieving robust itch relief while reducing the risk of the dermatitis flares observed with receptor blockade. The rapid onset, remarkable depth, and sustained durability of itch relief following a single dose of ATTO-1310 in this Phase 1b study are particularly impressive. These results give me great optimism that we may finally be approaching a treatment breakthrough for the millions of patients suffering from CPUO.”

Itch Relief and Lesional Improvements Following a Single Dose in Patients with High-Itch AD
In patients with high-itch AD, a rapid reduction in itch was observed as early as Week 2, with 39% of ATTO-1310-treated patients achieving PP-NRS4 vs. 25% with placebo. The ATTO-1310 response rate increased to 44% at Week 4 and was sustained through Week 12. In the pooled placebo group (n=8), the PP-NRS4 response rate increased from 25% at Week 4 to 75% at Week 12. In the more stringent itch-free or nearly itch-free (PP-NRS<2) analysis, 28% (5/18) of ATTO-1310-treated patients achieved a response at Week 12 vs. 13% (1/8) with placebo.

Patients with high-itch AD achieving at least a 4-point reduction from baseline (PP-NRS4):
% (n/N) of PP-NRS4 responders	Placebo (n=4)	4.5 mg/kg (n=8)	Placebo (n=4)	9 mg/kg (n=10)	Pooled placebo (n=8)	Pooled ATTO- 1310 (n=18)
Week 4	25% (1/4)	63% (5/8)	25% (1/4)	30% (3/10)	25% (2/8)	44% (8/18)
Week 12	50% (2/4)	50% (4/8)	100% (4/4)	40% (4/10)	75% (6/8)	44% (8/18)

Patients with high-itch AD achieving a worst itch score of less than 2, meaning they were itch-free or nearly itch-free status (PP-NRS<2):
% (n/N) of PP-NRS<2 responders	Pooled placebo (n=8)	Pooled ATTO-1310 (n=18)
Week 4	25% (2/8)	28% (5/18)
Week 12	13% (1/8)	28% (5/18)

In addition to itch relief, a single dose of ATTO-1310 led to rapid improvements in skin disease severity that deepened through Week 12, with response rates increasing across several stringent Eczema Area and Severity Index (EASI) and validated Investigator Global Assessment (vIGA) endpoints.

Patients achieving improvements in EASI (percentage change from baseline; %CFB) and at least 75% skin disease severity improvement (EASI-75)
	EASI %CFB						EASI-75
	Pooled placebo (n=8)		4.5 mg/kg (n=8)		9 mg/kg (n=10)		Pooled placebo (n=8)	4.5 mg/kg (n=8)	9 mg/kg (n=10)
Week 4	-17	%	-61%**		-51%*		0% (0/8)	38% (3/8)	20% (2/10)
Week 12	-28	%	-49	%	-62	%	13% (1/8)	25% (2/8)	60% (6/10)
p < 0.05; *p < 0.01; all p values are nominal.

Patients achieving at least 75%, 90%, or 100% skin disease severity improvement and clear or almost-clear skin (vIGA 0/1):
	EASI-75		EASI-90		EASI-100		vIGA 0/1
	Pooled placebo (n=8)	Pooled ATTO- 1310 (n=18)	Pooled placebo (n=8)	Pooled ATTO- 1310 (n=18)	Pooled placebo (n=8)	Pooled ATTO- 1310 (n=18)	Pooled placebo (n=8)	Pooled ATTO- 1310 (n=18)
Week 4	0% (0/8)	28% (5/18)	0% (0/8)	17% (3/18)	0% (0/8)	11% (2/18)	0% (0/8)	22% (4/18)
Week 12	13% (1/8)	44% (8/18)	0% (0/8)	22% (4/18)	0% (0/8)	17% (3/18)	13% (1/8)	39% (7/18)

“Itch is the most burdensome symptom of atopic dermatitis, profoundly affecting patients’ quality of life and driving treatment decisions,” said Jonathan Silverberg, MD, PhD, MPH, Professor of Dermatology at The George Washington University School of Medicine and Health Sciences. “Up to one-third of adults with AD experience severe itch despite having only mild-to-moderate skin lesions, a disease burden often underestimated by traditional severity measures. These patients remain underserved, with no approved systemic therapy. Given the central role of IL-31 in driving itch, a highly effective, long-acting biologic targeting this pathway could represent an important advance in AD treatment. The Phase 1b results with ATTO-1310 are particularly encouraging, demonstrating sustained improvements in both itch and skin lesions following a single dose, and provide a compelling rationale for further evaluation in Phase 2 studies.”

Phase 2 Program
The Company plans to initiate two Phase 2 trials of ATTO-1310. The ATTUNE-CPUO trial aims to enroll approximately 300 patients with CPUO across 78 sites in North America and the EU. The ATTUNE-AD trial aims to enroll approximately 255 patients with high-itch AD across approximately 60 sites in North America, the EU, and the Asia-Pacific region. Both trials are on track to initiate in the first half of 2027.

Virtual KOL Call Information
The Company will host a virtual KOL call today, Thursday, November 5, 2026, at 4:30 pm ET. The call will feature Brian Kim, MD, MTR, FAAD, and Jonathan Silverberg, MD, PhD, MPH, who will join the Company to provide their perspectives on the unmet need in CPUO and high-itch AD. The call will also review the positive 12-week topline results from the Phase 1b study of ATTO-1310. Click here to register for and attend the call.

A webcast of the call can also be found in the “Events & Presentations” section of Attovia’s website at https://investors.attovia.com. The webcast will be archived and available for replay for at least 30 days after the event.

About the Phase 1 Study of ATTO-1310
The Phase 1a portion evaluated single and multiple ascending doses of ATTO-1310 in healthy volunteers (HV). Phase 1b evaluated a single subcutaneous (SC) dose of ATTO-1310 (4.5 or 9 mg/kg) versus placebo in two patient populations: patients with CP (n=26), defined by Peak Pruritus Numerical Rating Scale (PP-NRS) score ≥7, pruritus lasting at least six months with no identifiable cause, and involvement of two or more body areas; and patients with high-itch AD (n=26), defined by PP-NRS score ≥7, Eczema Area and Severity Index (EASI) ≥7, and validated Investigator Global Assessment (vIGA) score ≥3.

The primary and secondary endpoints were safety, pharmacokinetics (PK), and immunogenicity; exploratory endpoints included clinical activity (PP-NRS, EASI, and vIGA) and pharmacodynamic markers. The previously reported interim analysis focused on Week 4 after a single dose of ATTO-1310; Week 4 was the last visit before rescue therapy was permitted. The topline results extend through Week 12.

About Attovia Therapeutics, Inc.

Attovia™ is a clinical-stage biopharmaceutical company developing next-generation biotherapeutics for immune-mediated diseases with high unmet need. All of its product candidates have been internally discovered using its ATTOBODY™ biparatopic biologics platform. Attovia’s ATTOBODY platform uses an evolution-driven, high-throughput process that allows for rapid discovery and creation of a high diversity of potential product candidates.

Attovia’s lead programs include ATTO-1310, an anti-IL-31 therapeutic in clinical development for chronic pruritic diseases; ATTO-2306, a long-acting bispecific antibody targeting IL-31 and IL-13 in IND-enabling studies for atopic dermatitis and other immune-mediated skin diseases; and ATTO-1091, a trispecific antibody targeting TL1A, IL-23p19, and integrin α4β7 in IND-enabling studies for inflammatory bowel disease. Attovia’s other programs include highly innovative conditional ‘AND’-gated bispecific immune cell survival blockers and multispecifics.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements reflect the current beliefs and expectations of management. All statements other than statements of historical fact are statements that could be deemed forward-looking statements, including, without limitation, statements concerning the Company’s future plans and prospects; any expectations regarding the safety or efficacy of ATTO-1310, ATTO-2306, and ATTO-1091, and other candidates under development; the ability of such candidates to treat their indications; and the planned timing of the Company’s clinical trials, data results, and further development of its product candidates. In addition, when or if used in this press release, the words “may,” “could,” “should,” “anticipate,” “believe,” “estimate,” “expect,” “intend,” “plan,” “will,” “predict,” and similar expressions and their variants, as they relate to the Company, may identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Although the Company believes the expectations reflected in such forward-looking statements are reasonable, the Company can give no assurance that such expectations will prove to be correct. Readers are cautioned that actual results, levels of activity, safety, performance, or events and circumstances could differ materially from those expressed or implied in the Company’s forward-looking statements due to a variety of factors, including risks and uncertainties related to the Company’s ability to advance its product candidates and obtain regulatory approval of and ultimately commercialize such product candidates, the timing and results of preclinical studies and clinical trials, the Company’s ability to fund development activities and achieve development goals, its ability to protect its intellectual property, general business and economic conditions, and risks related to the impact on its business of macroeconomic and geopolitical conditions, including inflation, volatile interest rates, tariffs, instability in the global banking sector, public health crises, and geopolitical conflicts. Further information on potential risk factors that could affect the Company’s business and its financial results is detailed under the heading “Risk Factors” included in the documents the Company files from time to time with the U.S. Securities and Exchange Commission. Accordingly, readers are cautioned not to place undue reliance on these forward-looking statements. These forward-looking statements speak only as of the date of this press release, and Attovia undertakes no obligation to revise or update any forward-looking statements to reflect events or circumstances after the date hereof.

Investor and Media Contacts

Attovia Therapeutics
Heather Armstrong
Head of Investor Relations
ir@attovia.com

PJ Kelleher
LifeSci Advisors LLC
617-430-7579
pkelleher@lifesciadvisors.com

Attovia Therapeutics Announces Positive Topline 12-Week Results from Phase 1b Study of ATTO-1310 in Patients with Chronic Pruritus and High-Itch Atopic Dermatitis