| Ticker | Status | Jurisdiction | Filing Date | CP Start | CP End | CP Loss | Deadline |
|---|
| Ticker | Case Name | Status | CP Start | CP End | Deadline | Settlement Amt |
|---|
| Ticker | Name | Date | Analyst Firm | Up/Down | Target ($) | Rating Change | Rating Current |
|---|
Sonnet's lead product, SON-1010 (IL12-FHAB), is being evaluated in combination with atezolizumab (Tecentriq®) in patients with advanced platinum-resistant ovarian cancer (PROC) (SB221)
Topline safety, cytokine, and efficacy data suggest a strong potential for clinical benefit using the current maximum dose of SON-1010
A second patient with PROC in the E6 combination cohort recently had a confirmed PR, so 2 out of 3 total patients had a tumor response at that dose
After completing enrollment of the expansion group at that top dose, a new E7 cohort has been added to examine the safety and effectiveness of a 25% higher maintenance dose of SON-1010
PRINCETON, N.J., Aug. 04, 2025 (GLOBE NEWSWIRE) -- Sonnet BioTherapeutics Holdings, Inc. (NASDAQ:SONN) (the "Company" or "Sonnet"), a clinical-stage company developing immunotherapeutic drugs targeting the tumor microenvironment (TME), today announced the expansion of its clinical study of patients with platinum-resistant ovarian cancer (PROC) (SB221). SB221 is a Phase 1b/2a dose-escalation and proof-of-concept study of the combination of SON-1010 (IL12-FHAB®) with atezolizumab (Tecentriq®), which is provided by Genentech, a member of the Roche Group. Enrollment of the expansion group using the highest maintenance dose from the monotherapy study (the E6 dose of 1200 ng/kg) has been completed, providing an opportunity to study the safety of the combination in a larger population and get a preliminary efficacy readout later this year. A second partial response (PR) based on GCIG criteria was recently observed at the 2-month timepoint and confirmed by RECIST criteria 2 months later in a patient with PROC at that dose. Thus, 2 of the 3 patients (66%) at the E6 dose of SON-1010 had a significant tumor response. Given the strong safety profile at the top dose, the Safety Review Committee (SRC) recommended adding an E7 cohort using a maintenance dose of 1500 ng/kg to study its safety and effectiveness before proceeding to the randomized Phase 2a portion, which will evaluate patients with PROC at one of the two highest doses compared to the standard of care.
Dose escalation results from the SB101 study (previously disclosed), Sonnet's monotherapy trial of SON-1010 in patients with advanced solid tumors, showed a clinical benefit rate in 5 of 6 patients (83%) at the 1200 ng/kg dose, including one patient with soft tissue sarcoma (STS) who had a PR. That study is also being expanded, using SON-1010 alternating with trabectedin (Yondelis®) in patients with STS. In the SB221 study, SON-1010 combined with atezolizumab has also shown acceptable safety signals and clinical benefit during dose escalation, with controlled induction of IFN. "We are very pleased with the progress of the SB221 study and look forward to investigating the effect of a higher dose of SON-1010, with the hope that it could maximize efficacy without inducing cytokine toxicity," said Richard Kenney, M.D., Sonnet's Chief Medical Officer. "Top line readouts from this combination study are expected in the fourth quarter of 2025."
Robert Wenham, M.D., Chair of GYN Oncology at Moffitt Cancer Center, Key Opinion Leader and lead investigator for the SB221 study added, "The strong but controlled induction of IFN is particularly important, as that is necessary for immunotherapeutic control of tumors, but it also induces PD-L1 expression on tumor cells, which contributed to our interest in the combination of SON-1010 with atezolizumab. PROC patients typically have low response rates to currently approved therapies. While more data are needed from the expansion group, the two PRs at the E6 dose are very exciting and represent some of the best data to date in support of a pure combination immunotherapy approach. Other emerging data recently verified a role for IO with chemotherapy in this setting, so I am looking to the future for how we might change the face of this disease with a new drug like SON-1010."
"The primary goal for the first part of this study was to establish the maximum dose of SON-1010 in combination with atezolizumab as an immune checkpoint inhibitor (ICI), and to provide better evidence of efficacy in the expansion group," said Raghu Rao, Sonnet's Interim Chief Executive Officer. "We will follow the patients currently being treated at the E6 dose to assess longer-term safety and tumor responses, and look forward to studying a 25% higher dose in the E7 cohort before selecting the best dose and moving to Part 2. Sonnet continues to seek partnership opportunities to help support the later stage development of SON-1010."
Posted In: SONN
