Concerto Biosciences Announces Positive Topline Results from Phase 1b Clinical Trial of ENS-002 in Patients with Atopic Dermatitis

Primary safety endpoint achieved with zero drug-related adverse events; secondary outcomes showed eczema improvement and targeted suppression of Staphylococcus aureus without loss of protective skin microbes

CAMBRIDGE, Mass., Oct. 28, 2025 /PRNewswire/ -- Concerto Biosciences®, a clinical-stage biotech company developing microbial products for therapeutics and consumer markets, today announced positive topline results from its first-in-human Phase 1b clinical trial evaluating ENS-002, a topical three-strain live biotherapeutic product for mild-to-moderate atopic dermatitis (AD).

ENS-002 was safe and well-tolerated with no drug-related adverse events, meeting its primary endpoint. Secondary endpoints were positive: eczema symptoms improved, and Staphylococcus aureus (S. aureus)—a bacterium known to increase the frequency and severity of flares—was suppressed without disturbing the skin's beneficial microbes.

"ENS-002 does not behave like an immunosuppressant or an antibiotic," said Cheri Ackerman, PhD, Cofounder and CEO of Concerto Biosciences. "It's a new class of medicine with a safety profile that enables what current therapies cannot: flexible, low-burden regimens that could extend beyond flare control into year-round maintenance. The completion of our Phase 1b study represents an important step toward a new, patient-friendly paradigm with an attractive safety profile for eczema treatment."

Trial Design

The Phase 1b study was designed to establish safety and investigate early signals of efficacy to better inform dose, schedule, and endpoints for Phase 2.

The open-label trial enrolled eight adults with mild-to-moderate AD into two sequential dosing cohorts (Cohort 1: lower dose; Cohort 2: higher dose). Each cohort was followed by a one‑month post‑treatment monitoring period to assess durability of effect.

The primary endpoint was safety and tolerability, assessed by the incidence of adverse events, dose-limiting toxicity, laboratory abnormalities, and physical exam. Secondary endpoints included ENS-002 strain levels (treated and untreated sites), S. aureus levels (treated and untreated sites), and eczema severity scores. Exploratory endpoints included microbiome diversity and levels of key commensal taxa.

Assessments were conducted at baseline, throughout the ENS-002 administration period, and throughout a one‑month post-administration follow‑up.

Key Results

• Safe and well-tolerated: All eight participants completed administration with no drug‑related or serious adverse events and no discontinuations.
  
  
• Dose-dependent and durable clinical improvement: Both cohorts showed reductions in eczema severity during the 1–2 weeks of administration that persisted through the post-administration phase. Overall, Eczema Area and Severity Index (EASI) improved in 3/4 participants in Cohort 1 (lower dose) and 4/4 participants in Cohort 2 (higher dose); and peak pruritus decreased in 2/4 participants in Cohort 1 and in 4/4 participants in Cohort 2.
  
  
• Strong drug presence: ENS-002 reached appreciable relative abundance at treated sites during dosing.
  
  
• Targeted suppression of S. aureus: On treated S. aureus–positive lesions, S. aureus levels fell sharply—often to near zero—and no new S. aureus growth appeared on previously negative or untreated skin.
  
  
• Preservation of protective microbes: Naturally occurring skin bacteria, including Corynebacterium, coagulase-negative Staphylococcus, and Micrococcus, fluctuated minimally throughout administration and follow-up, distinguishing ENS-002 from antibiotics that disrupt healthy microbial communities.

"The combination of targeted S. aureus suppression, preservation of the healthy skin microbiome, and measurable symptom improvement is rare—and exciting," said Peter Lio, M.D., Founder of the Chicago Integrative Eczema Center and member of Concerto's Scientific Advisory Board. "The possibility of offering patients a therapy that's safe enough for ongoing use and simple enough to stick with could fundamentally change how we manage mild-to-moderate disease."

Next Steps

Concerto plans to conduct vehicle-controlled clinical assessments of ENS‑002 safety and efficacy across adult and pediatric patients. In addition, a future study to evaluate lower‑frequency maintenance dosing to verify durability and remittive effect is planned.

"From the beginning, we built ENS-002 with scientific rigor and operational precision, qualities that enabled us to translate complex microbial science into the clinic efficiently," said Bernardo Cervantes, PhD, Cofounder and COO of Concerto Biosciences. "That same discipline now positions us to run a focused, high-quality Phase 2 trial designed to validate efficacy and deliver meaningful benefit for patients."

About Atopic Dermatitis, S. aureus, and ENS-002

In atopic dermatitis (AD), Staphylococcus aureus is present in 60–93% of patients and drives flares through virulence factors controlled predominantly by its agr quorum sensing system. These virulence factors include PSMα, which induces inflammation, and the V8 protease, which triggers itch. Broad-spectrum antibiotics can knock down S. aureus temporarily, but they also wipe out protective commensals, removing natural checks on S. aureus and leaving the niche open for rapid recolonization—undermining durability and tolerance.

ENS-002 consists of three skin-derived, clonal, commensal, and non-pathogenic bacterial strains delivered at equal ratio and has been designed to inhibit S. aureus proliferation and virulence while preserving the skin's beneficial microbes. ENS-002's therapeutic goal is to safely reduce flare frequency and severity without systemic impacts on the immune system or microbiome.

ENS‑002 was discovered using Concerto's kChip platform, which screened millions of microbial combinations to identify a trio of skin‑dwelling strains that, together, robustly inhibit S. aureus behaviors across varied community contexts.

About Concerto Biosciences

Concerto Biosciences pioneers science-first human health products powered by the most comprehensive and accurate map of the microbial world ever achieved. Enabled by its MIT-developed combinatorial screening platform kChip, Concerto's map incorporates 40+ million experimental measurements of microbial community behavior. These data train the company's proprietary AI, kAI, to expand the map further still. From this unique vantage, hundreds of robust, synergistic, and multifunctional microbe-based ingredient hits stand out in plain view. The first is ENS-002, a three-strain biotherapeutic that successfully completed Phase 1 clinical testing for atopic dermatitis. Concerto is now unleashing the full might of its platform and data in consumer skin health, charting new domains with kChip+kAI—from intimate health to oral care to infant nutrition—to convert the potential of microbes everywhere into a foundation of innovation and health.

To learn more about Concerto Biosciences, visit www.concertobio.com. Follow us at concerto-biosciences.

SOURCE Concerto Biosciences