Phase 1b/2a Trial of SON-080 for CIPN Achieves Preliminary Safety Goals

Sonnet BioTherapeutics, a clinical-stage company, has announced that its Phase 1b/2a clinical trial of SON-080 has been approved to advance to Phase 2. The trial, known as SB211, is focused on patients with persistent Chemotherapy-Induced Peripheral Neuropathy (CIPN) and utilizes a novel version of recombinant human Interleukin-6 (rhIL-6). The independent Data Safety Monitoring Board (DSMB) reviewed the safety and tolerability of SON-080, finding it consistent with previous IL-6 candidates, thus meeting the Phase 1b safety goal.

The trial investigates a low dose of rhIL-6, which is identical in amino acid sequence to the native molecule. The aim is to achieve serum levels that mimic those induced by moderate exercise, which is known to prompt the natural healing of nerves, muscles, and bones. IL-6, a pleiotropic cytokine, is involved in various physiological processes such as tissue repair and glucose homeostasis. However, at higher levels, it can lead to acute pathological inflammation. Preclinical models suggest that low dose rhIL-6 may stimulate nerve regrowth, reducing pain and normalizing physiological conditions affected by nerve degeneration.

In Phase 1b of the SB211 study, the DSMB reviewed the safety and tolerability of SON-080 in the initial nine patients. The adverse events observed were mild to moderate, with injection site reactions and symptoms like fatigue and body aches being the most prominent. All adverse events were found to be transient and reversible, leading the DSMB to conclude that the study could proceed to Phase 2.

Sonnet plans to use the safety data from the trial to support the initiation of a Phase 2 clinical trial in Diabetic Peripheral Neuropathy (DPN), a larger indication, once a potential partnership is established. The company has received significant interest in partnering for the DPN indication due to its larger market opportunity.

The SB211 study is designed to evaluate the safety, pharmacokinetics, pharmacodynamics, and initial efficacy of SON-080 compared to placebo. The drug is self-administered subcutaneously three times a week in patients with CIPN that has lasted for at least three months post-chemotherapy. The primary endpoint of the study is the safety and tolerability of SON-080, with secondary endpoints measuring pharmacokinetics, pharmacodynamics, and immunogenicity. Preliminary efficacy is assessed using standardized pain questionnaires.

Sonnet BioTherapeutics is an oncology-focused biotechnology company with a proprietary platform called FHAB (Fully Human Albumin Binding), which is designed to target tumor and lymphatic tissue, optimizing the safety and efficacy of immune modulating biologic drugs. The FHAB technology is a modular construct that can be used to enhance various therapeutic classes, including cytokines, peptides, antibodies, and vaccines.

The company is currently seeking a partner to move forward with the Phase 2 study in DPN, which offers a significant market opportunity. The potential of SON-080 to treat the underlying causes of peripheral neuropathy, rather than just masking symptoms, positions it as a unique treatment approach.