Avalo Therapeutics Reports Topline Phase 2 Success for Abdakibart in Hidradenitis Suppurativa

Avalo Therapeutics has reported positive topline results from the phase 2 LOTUS trial (NCT06603077) evaluating abdakibart (AVTX-009) in adults with moderate to severe hidradenitis suppurativa (HS).¹ The trial met its primary endpoint at both dose levels, demonstrating statistically significant improvements compared with placebo.

"We are proud to report that abdakibart has delivered a strong, consistent, and deep response across both the HiSCR75 and HiSCR50 endpoints in our phase 2 trial. This achievement powerfully validates the clinical promise of IL-1β inhibition for HS," said Garry Neil, MD, Chief Executive Officer of Avalo Therapeutics. “This de-risking data set gives us tremendous confidence to advance abdakibart into a pivotal phase 3 registrational program. With a differentiated and patient-friendly potential monthly dosing regimen, we aim to offer a truly innovative mechanism of action to the HS community. Our heartfelt thank you goes to the patients, caregivers, investigators, and site teams whose dedication made this successful phase 2 trial possible."¹

Primary and Secondary Endpoints

The randomized, double-blind, placebo-controlled study enrolled 253 patients in October 2025 and assessed efficacy, safety, and tolerability over a 16-week treatment period.² Participants were randomized in a 1:1:1 ratio to receive 1 of 2 abdakibart dosing regimens or placebo. One group received a 600 mg loading dose followed by 300 mg every 4 weeks, while the second group received a 300 mg loading dose followed by 150 mg every 2 weeks.

The primary endpoint was the proportion of patients achieving Hidradenitis Suppurativa Clinical Response 75 (HiSCR75) at week 16. HiSCR75 response rates were 42.2% in the 150 mg group and 42.9% in the 300 mg group, compared with 25.6% in the placebo arm. These represent the highest absolute improvements observed in trials of similar size or larger evaluating this endpoint, and the consistency of response across both dosing strategies suggests a robust treatment effect.

Abdakibart also demonstrated statistically significant improvements across key secondary endpoints. These included:

• Proportion of participants achieving HiSCR50 and HiSCR90
• Change from baseline in International HS Severity Score System (IHS4)
• Change in draining fistula count, abscess, and inflammatory nodule count
• Proportion of participants achieving at least a 30% reduction in Patient’s Global Assessment of Skin Pain (PGA Skin Pain).

Importantly, treatment responses were similar in patients regardless of prior biologic exposure.

MORE ON HS

Safety and Tolerability Profile

The safety profile of abdakibart was favorable over the 16-week study period. Treatment-emergent adverse events occurred at similar rates across both active treatment arms and the placebo group. The most commonly reported adverse events were headache and nausea.

Most adverse events were mild to moderate in severity. Notably, no unexpected safety signals were identified. There were no reported cases of neutropenia, serious infections, or opportunistic infections.

Clinical Implications and Next Steps

Abdakibart, the company’s lead clinical candidate, is a high-affinity monoclonal antibody designed to neutralize IL-1β. Abdakibart neutralizes its activity and may reduce downstream inflammatory signaling pathways implicated in HS lesion formation and maintenance. This mechanism represents a differentiated approach compared with currently available therapies for HS, which may offer an additional option for patients with inadequate response to existing treatments.

Based on these findings, Avalo plans to advance abdakibart into a registrational phase 3 program. Full results from the LOTUS trial are expected to be presented at an upcoming medical congress.

“These phase 2 results are highly promising for the HS community,” John Frew, PhD, professor of dermatology at the University of New South Wales in Sydney, Australia, said. “Achieving this level of improvement suggests that IL-1β inhibition with abdakibart may offer a meaningful new therapeutic option for people with HS who continue to struggle with this disease. The physical and emotional burden of HS is profound, and I am encouraged to see an investigational therapy showing such robust and clinically relevant results.”¹

References

1. Avalo Therapeutics Achieves Positive Topline Results in Phase 2 LOTUS Trial of Abdakibart (AVTX-009) in Moderate to Severe Hidradenitis Suppurativa. News release. GlobeNewswire. Published May 5, 2026. Accessed May 6, 2026. https://www.globenewswire.com/news-release/2026/05/05/3288197/0/en/avalo-therapeutics-achieves-positive-topline-results-in-phase-2-lotus-trial-of-abdakibart-avtx-009-in-moderate-to-severe-hidradenitis-suppurativa.html?_gl=1*1q6dxyr*_up*MQ..*_ga*MTk0ODQyMzkwOS4xNzc4MDcyNzEx*_ga_B6167QB2TF*czE3NzgwNzI3MTAkbzEkZzAkdDE3NzgwNzI3MTAkajYwJGwwJGgxODUyMzEyMzU.*_ga_ERWPGTJ5X8*czE3NzgwNzI3MTAkbzEkZzAkdDE3NzgwNzI3MTAkajYwJGwwJGgw

2. Avalo Therapeutics announces completion of enrollment in phase 2 LOTUS trial of AVTX-009 for the treatment of hidradenitis suppurativa. News release. Avalo Therapeutics. Published October 29, 2025. Accessed May 6, 2026. https://www.globenewswire.com/news-release/2025/10/29/3176254/0/en/Avalo-Therapeutics-Announces-Completion-of-Enrollment-in-Phase-2-LOTUS-Trial-of-AVTX-009-for-the-Treatment-of-Hidradenitis-Suppurativa.html