SON-1010 Generates Safe Results in Advanced Sarcoma

A clinical trial has reported positive safety findings of SON-1010 among adult patients with advanced leiomyosarcoma (LMS) or liposarcoma (LPS).

Findings from first safety review of the expansion cohort of the phase 1 SB101 clinical trial were announced in a news release from Sonnet BioTherapeutics Holdings, Inc., a clinical-stage company that is developing targeted and immunotherapeutic drugs.

SON-1010, as explained by the National Cancer Institute, is a targeted immunotherapy utilizing an engineered form of the cytokine interleukin-12 (IL-12) to activate a patient’s immune system in order to kill tumor cells and inhibit tumor cell proliferation.

The SB101 Safety Review Committee found that among patients in the study’s expansion cohort, who are receiving SON-1010 in combination with Yondelis (trabectedin) chemotherapy, after an average treatment of more than two months one patient had progressed and six were reported to be tolerating treatment. According to the news release, the Safety Review Committee found no unexpected toxicities in the first seven patients at the maximum tolerated dose.

“Our physicians are always working to improve the outcomes in sarcoma and very pleased to continue to support the expanded SB101 trial,” commented Dr. Sant Chawla, principal investigator at the Sarcoma Oncology Center in Santa Monica, California. “We have a wealth of experience with [Yondelis] and believe that SON-1010 has the ability to improve its therapeutic effectiveness, given that SON-1010 as a clinical trial monotherapy has already demonstrated clinical benefit in advanced sarcoma patients, including a partial response. LPS and LMS are the most common types of sarcoma, which are difficult diseases to treat. While the approval of [Yondelis] in the U.S. has helped, there is room for improvement in all types of STS and the drug appears to have utility in the relapsed ovarian cancer setting as well. The safety of SON-1010 in combination with [Yondelis] is encouraging at this stage and we look forward to the results from the larger group of patients for further clinical trials.”

The SB101 clinical trial is currently recruiting, according to its listing on clinicaltrials.gov, with an estimated eventual enrollment of 36 patients.

Side effects that were considered to be related to either drug were all mild or moderate. The annual review that included all 30 patients dosed to date in the study revealed that common side effects considered related to SON-1010 as a standalone or combination therapy were fatigue, fever, chills and myalgia in 15% or more, with moderate fatigue being the only related side effect in two or more patients who had also received treatment with Yondelis.

The news release further reported that five of the six patients (83%) in the high-dose SON-1010 monotherapy group showed stable disease at four months, with four patients continuing on the trial at six months with no new safety concerns and a partial response in one of those patients persisting. Thirteen of the 24 patients (54%) who were studied during SON-1010 dose escalation were found to have evidence of clinical benefit from SON-1010 monotherapy.

“The goal for the expansion cohort is to assess combination therapy in earlier-stage patients with [soft-tissue sarcomas], which provides an exciting opportunity to evaluate the potential for SON-1010 to turn ‘cold’ tumors ‘hot’ and improve the response of trabectedin in a licensed chemotherapy indication,” added Pankaj Mohan, Sonnet founder and CEO. “We believe the results of this expansion cohort will position SON-1010 for a larger Phase 2 study that could establish the combination of SON-1010 and trabectedin as a new and potentially improved treatment for STS at an earlier stage.”

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