Tigilanol Tiglate Shows Early Efficacy in Soft Tissue Sarcomas

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Eight out of 10 evaluable patients with soft tissue sarcoma who received tigilanol tiglate (Stelfonta) achieved either complete ablation or partial ablation of their treated tumors or tumor segments at any time, according to findings from stage 1 of the phase 2a QB46C-H07 trial (NCT05755113).1

Eighty-one percent of 27 treated tumors demonstrated complete or partial responses (PRs) as the best observed response; 52% showed complete ablation, defined as 100% reduction in tumor volume, and 30% showed partial ablation, defined as at least 30% reduction in tumor volume. Notably, none of the 14 complete responses (CRs) recurred at a 6-month time point, suggestive of response durability.

Safety data indicated that the most common adverse effects experienced were local pain, swelling, and necrosis, which were expected and associated with the local action with the drug. Safety was assessed in 11 patients who received treatment and was determined to be well tolerated.

“We are delighted with the outcomes from stage 1 of our phase 2a soft tissue sarcoma trial. Tigilanol tiglate met both its primary and secondary end points and delivered patients an impressive 80% [ORR] in injected tumors,” Stephen Doyle, chief executive officer and managing director of QBiotics Group Limited, stated in a news release. “Importantly, none of the 14 fully ablated (destroyed) tumours had recurred by the 6-month follow-up period, suggesting tigilanol tiglate may provide long-term benefit for patients. Given soft tissue sarcoma is a challenging cancer to treat, achieving this level of clinical activity is highly encouraging.”

The trial, which is being conducted in 2 stages, enrolled patients with soft tissue sarcoma who were at least 18 years of age, had advanced and/or metastatic disease of the body wall or extremities, an ECOG performance status no higher than 2, a life expectancy longer than 12 weeks, and acceptable renal and hepatic function per investigator assessment.2 Patients (n = 11) received the intratumoral agent at 0.5 mg/cm3 tumor volume to at least 1 of their tumors.1

ORR of injected tumors vs baseline served as the trial’s primary efficacy end point, and secondary end points comprised safety, tolerability, and pharmacokinetics. Exploratory end points included local rate of recurrence at the injection site at 6 months after initial injection and leveraging biopsy samples to assess tumor responses. Changes in tumor biomarkers is also being evaluated.

“The clinical activity of tigilanol tiglate, which we observed in multiple types of soft tissue sarcoma, was encouraging,” Edmund Bartlett, MD, principal trial investigator at Memorial Sloan Kettering Cancer Center, added in the news release. “I look forward to expanding our experience with this treatment and determining how to integrate it into the care of patients with soft tissue sarcoma.”

Previous data from a phase 1 study done in Australia showed that 6 of 22 patients with accessible cutaneous, subcutaneous or nodal tumors refractory to conventional therapy responded to treatment with the agent per RECIST 1.1 criteria.3 In the overall cohort, a CR was achieved in 1 patient who achieved the agent at dose level of 2.4 mg/m2; PRs were achieved in 3 patients who received the agent at the following dose levels: 0.6 mg/m2, 0.24 mg/m2, and 2.4 mg/m2. Ten patients had stable disease (SD), 1 had progressive disease, and 1 was not response evaluable. In the local effect cohort of patients who received an appropriate dose of tigilanol tiglate based on tumor size (n = 6), 3 experienced a CR and 3 had SD.

The FDA granted an orphan drug designation to tigilanol tiglate as a potential option for use in patients with soft tissue sarcoma in February 2024.4

References

1. QBiotics reports 80% objective response rate in injected tumours in stage 1 of phase IIa clinical trial of tigilanol tiglate for soft tissue sarcoma. News release. QBiotics Group Limited. June 25, 2025. Accessed June 26, 2025. https://qbiotics.com/announcement/qbiotics-reports-80-objective-response-rate-in-injected-tumours-in-stage-1-of-phase-iia-clinical-trial-of-tigilanol-tiglate-for-soft-tissue-sarcoma
2. A clinical study to investigate the efficacy of intratumoral tigilanol tiglate in soft tissue sarcoma. ClinicalTrials.gov. Updated February 20, 2025. Accessed June 26, 2025. https://clinicaltrials.gov/study/NCT05755113
3. Panizza BJ, de Souza P, Cooper A, Roohullah A, Karapetis CS, Lickliter JD. Phase I dose-escalation study to determine the safety, tolerability, preliminary efficacy and pharmacokinetics of an intratumoral injection of tigilanol tiglate (EBC-46). EBioMedicine. 2019;50:433-441. doi:10.1016/j.ebiom.2019.11.037
4. QBiotics drug tigilanol tiglate awarded Orphan Drug Designation for patients with soft tissue sarcoma. News release. QBiotics Group Limited. February 16, 2024. Accessed June 26, 2025. https://qbiotics.com/investors/announcements/26-news/377-qbiotics-drug-tigilanol-tiglate-awarded-orphan-drug-designation-for-patients-with-soft-tissue-sarcoma