WALTHAM, Massachusetts, and HANGZHOU, China, August 13, 2026
Photys Therapeutics, Inc. and Polymed Biopharmaceuticals, Inc. announced the initiation of a Phase 1 clinical trial evaluating PHT-776/HPB-143, an investigational oral IRAK4-targeted PROTAC degrader designed for the treatment of autoimmune and inflammatory diseases. The first-in-human study has begun dosing healthy participants at Huashan Hospital, affiliated with Fudan University. The trial will evaluate the safety, tolerability and pharmacokinetic profile of PHT-776/HPB-143 through single-ascending dose and multiple-ascending dose cohorts. The program represents a clinical milestone for both companies as they advance a targeted protein degradation approach against IRAK4, a signaling protein involved in inflammatory pathways associated with several immune-mediated diseases.
PHT-776 Targets IRAK4 Through Targeted Protein Degradation
PHT-776/HPB-143 is an oral PROTAC designed to selectively and efficiently degrade IRAK4, rather than simply inhibit its activity. IRAK4 plays an important role in inflammatory signaling and has been implicated in diseases including hidradenitis suppurativa, atopic dermatitis, psoriasis and ulcerative colitis. According to the companies, preclinical studies showed that PHT-776/HPB-143 achieved high oral bioavailability, potent activity at low doses across multiple disease models and a broad preclinical safety window. The companies also reported no observed cardiovascular effects in their preclinical evaluations. These findings provide the scientific rationale for advancing the candidate into human testing, although the clinical trial will be required to determine whether the preclinical profile translates into meaningful safety, pharmacokinetic and therapeutic advantages in humans. As an investigational therapy, PHT-776/HPB-143 has not been approved by regulatory authorities for any indication.
Photys and Polymed Expand PROTAC Development Collaboration
The Phase 1 program builds on a 2025 licensing agreement under which Polymed granted Photys exclusive rights to develop and commercialize PHT-776/HPB-143 outside Greater China and Southeast Asia. Polymed is developing PROTAC and degrader antibody conjugate technologies intended to improve the therapeutic index of targeted protein degradation medicines. Photys is advancing proximity-based therapeutic approaches through its PHICS™ and tPRIME™ platforms, alongside PROTAC programs targeting autoimmune, inflammatory, oncology and cardiometabolic diseases. The companies believe PHT-776/HPB-143 could potentially offer a differentiated approach to IRAK4 modulation because of its oral administration and targeted protein degradation mechanism. The initial clinical cohorts have already been dosed at Huashan Hospital, providing an early step toward generating human safety and pharmacokinetic data. Clinical validation remains the key next milestone, particularly because promising preclinical activity does not guarantee comparable performance in patients.
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Phase 1 Study to Establish Initial Human Safety Profile
The Phase 1 trial is expected to provide the first clinical assessment of PHT-776/HPB-143 and will focus initially on determining how the investigational drug is tolerated and behaves in humans. Single-ascending and multiple-ascending dose cohorts will allow researchers to evaluate safety across increasing exposure levels while characterizing pharmacokinetic parameters. Data generated during the study could help determine appropriate dose ranges and inform subsequent clinical development in patients with inflammatory and autoimmune diseases. The program is particularly relevant to the growing field of targeted protein degradation, where PROTAC molecules are designed to recruit cellular degradation machinery to remove disease-associated proteins. If the clinical profile supports continued development, Photys and Polymed could advance PHT-776/HPB-143 toward patient studies in selected inflammatory indications. However, Phase 1 results will be critical for determining whether the candidate’s preclinical advantages can be demonstrated clinically and whether further development is justified.
Source: Photys Therapeutics,press release
