Committed to Significantly Enhancing Immunotherapy

Committed to Significantly Enhancing Immunotherapy

Bi-specific biologic drugs are actively being pursued as the next generation of immunotherapies. Sonnet’s versatile platform has been demonstrated to improve delivery of the active drug(s) to the tumor, as well as to help overcome past challenges with cytokine-based treatments, which are powerful tools in improving immunotherapy response rates.

Checkpoint inhibitors are the cornerstone of current cancer immunotherapy. These antibody-based approaches can be very effective when the patient’s immune response to a tumor has been activated. However, adequate activation does not occur in the majority of patients. To reach their potential, checkpoint inhibitors will need other agents to help activate the immune response; cytokines are a proven method for doing so. By addressing past challenges here, Sonnet aspires to unleash the true potential of checkpoint inhibition treatments.

Addressing Key limitations of Interleukins

The National Cancer Institute ranks certain interleukins (IL12, IL15, IL2) as top cancer targets, however, their therapeutic utility has some key limitations:

Short pK

Due to their small size, interleukins have a short half-life, passing quickly out of the body. This means that high doses are required to generate a response. However, when high doses are administered, severe toxicity becomes a concern.


Interleukins disperse around the body and do not specifically seek tumor tissue. This presents challenges in delivering sufficient quantities of interleukins to the tumor environment.

The Sonnet Solution

We have developed a proprietary Fully Human Albumin Binding construct (FHAB) with the following key features:

  • Extended pK: The Sonnet FHAB features a half-life of 2-4 weeks.
  • Targeted delivery: The Sonnet FHAB attaches to albmumin, which targets a protein overexpressed by tumors. This leads to selective accumulation at tumor sites.
  • Versatile Use: Sonnet’s FHAB technology can provide a vehicle for a variety of interleukins and other priority immunotherapy molecules.
  • Single- or Bi-Specific Activity: The Sonnet FHAB platform can accommodate a single- or bi-specific mechanism of action.

Our proof-of-concept data demonstrates the following improvements for interleukin therapies:

  • Longer half-life means interleukins can be administered in lower, safer doses.
  • Tumor specificity ensures that interleukins accumulate at the tumor, resulting in improved immune response at the tumor, and reducing the likelihood for toxicity elsewhere.