BRISBANE, Australia, June 25, 2025 /PRNewswire/ --

• Positive data from Stage 1 of the Phase IIa clinical trial (QB46C-H07) evaluating QBiotics' small molecule, tigilanol tiglate in 11 (10 evaluable) patients with advanced Soft Tissue Sarcoma (STS).
• An Objective Response Rate (ORR) of 80% was achieved, based on the Best Observed Response (BOR) at any time during the study, indicating 8 out of 10 evaluable patients saw either complete ablation (100% reduction in volume) or partial ablation (≥30% reduction in volume) of treated tumours.
• 22 of the 27 (81%) injected tumours across all patients showed complete or partial ablation (14 showing complete ablation and 8 showing partial ablation).
• None of the 14 completely ablated tumours recurred at 6 months, indicating tigilanol tiglate may provide durable responses.

QBiotics Group Limited (QBiotics) is pleased to announce final efficacy and safety data from the first of its two stage, Phase IIa clinical trial in patients with Soft Tissue Sarcoma (STS).

STS is a rare type of cancer that generally forms as a painless lump (tumour) in any one of the soft tissues in the body. There were approximately 128,000 new cases of STS globally in 2023, with the incidence growing at 0.54% per year.^[1]

QBiotics' CEO and Managing Director, Stephen Doyle commented, "We are delighted with the outcomes from Stage 1 of our Phase IIa Soft Tissue Sarcoma trial. Tigilanol tiglate met both its primary and secondary endpoints and delivered patients an impressive 80% Objective Response Rate in injected tumours. 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."

"Our thanks to every trial patient, and also to the trial Investigators, Dr. Edmund Bartlett and his team at Memorial Sloan Kettering Cancer Center in New York. Given the positive results from Stage 1 of the trial – and compelling investigator reports that tigilanol tiglate may improve responses to systemic therapies in metastatic STS – we have moved ahead with the expansion arm of the study, announced late last year."

Dr. Edmund Bartlett, Principal Trial Investigator at Memorial Sloan Kettering Cancer Center commented, "The clinical activity of tigilanol tiglate, which we observed in multiple types of soft tissue sarcoma, was encouraging. 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." 

ABOUT TRIAL QB46C-H07

QB46C-H07 (Clinical trial registration, NCT05755113) is a Phase IIa, open label, clinical trial evaluating the preliminary efficacy and safety of intratumoural tigilanol tiglate in patients with a range of advanced and/or metastatic STS. QB46C-H07 is being conducted in two stages: Stage 1 is a pilot trial in 10 patients. Stage 2 is an expansion trial. The results of Stage 1 are reported here.

Eleven patients were administered tigilanol tiglate (0.5 mg tigilanol tiglate/cm3 tumour volume) to one or more of their tumours. Ten patients were included in the response evaluable population (where patients had a tumour assessment at both baseline and at 28 days post-treatment).

The primary efficacy endpoint was Objective Response Rate (ORR) of injected tumours, compared to baseline. ORR was defined as the proportion of patients who achieved complete ablation (100% reduction in volume) or partial ablation (≥ 30% reduction in volume) of treated tumours and/or tumour segments following one or more treatments (up to 5 treatments) with tigilanol tiglate. Patients who achieved a ≥ 30% reduction in volume, irrespective of the number of treatments they received, were considered to have a response to tigilanol tiglate.

Secondary endpoints include safety and tolerability assessments, and pharmacokinetics.

Exploratory endpoints include local rate of recurrence at the injection site at 6 months post-initial injection, and assessment of tumour response in biopsy samples. Surgical specimens and blood samples were used to assess changes in tumour biomarkers.

Efficacy and Safety Outcomes

The ORR was 80% indicating 8 out of 10 evaluable patients achieved either complete or partial ablation of their treated tumours or tumour segments at any time during the study (Best Observed Response, BOR). There was a median of 2 treatments of tigilanol tiglate per patient (range 1 to 5). At the tumour level, 22 of 27 (81%) treated tumours showed either complete or partial responses as the Best Observed Response. 14 out of 27 tumours (52%) demonstrated complete ablation, while 8 out of 27 tumours (30%) demonstrated partial ablation.

These results indicate a high level of efficacy for tigilanol tiglate in achieving complete or partial tumour ablation. Importantly, none of the complete responses (n=14) recurred by 6 months, the follow-up period, indicating tigilanol tiglate may provide durable responses.

All 11 tigilanol tiglate treated patients were included in the safety evaluation. Tigilanol tiglate was well tolerated. Most of the Adverse Events (AEs) were expected and related to the local action of the drug (e.g. local pain, swelling, necrosis).

Conclusions

Overall, the study results indicate tigilanol tiglate is well tolerated and shows promising efficacy in reducing tumour volume, with 80% of patients experiencing complete (100%) ablation or partial (≥30%) ablation of their tumours. The absence of tumour recurrence in cases achieving a complete response further underscores tigilanol tiglate's potential as an effective treatment option for soft tissue sarcomas and possibly other solid tumours.

The promising tumour responses reported here, together with observations that three patients exhibited better than expected responses to subsequent systemic therapy (as presented at the Connective Tissue Oncology Society (CTOS) Annual Meeting in November 2024),^[2] have supported the progression of the QB46C-H07 study to Stage 2. The trial expansion (referred to as Stage 2) aims to further investigate the clinical utility and therapeutic potential of tigilanol tiglate in patients with STS. Stage 2 of the trial is opening shortly at Memorial Sloan Kettering Cancer Center in New York, USA.

References

1. GlobalData®, American Cancer Society, Cancer Australia, Cancer Research UK, Canadian Cancer Society.
2. Bartlett et al, 2024. The Connective Tissue Oncology Society (CTOS) Annual Meeting, Nov 13-16, 2024, San Diego, USA.

NOTES FOR EDITORS

ABOUT QBIOTICS

QBiotics is an unlisted, public, Australian life sciences company that seamlessly connects scientific discovery, development and commercialisation to harness the power of nature to treat diseases of high unmet need.  

Our current clinical focus is on novel treatments for cancer and debilitating chronic wounds. We also have an early-stage antibiotics program.

QBiotics' lead molecule, tigilanol tiglate, is a novel, small molecule with the potential to treat a broad range of solid tumours. It is currently in Phase II clinical trials in two indications: soft tissue sarcoma (STS) and head and neck cancer (HNC). Tigilanol tiglate was granted Orphan Drug Designation by the US FDA for the treatment of STS in February 2024.

A veterinary formulation of tigilanol tiglate (STELFONTA®) is approved for the treatment of canine mast cell tumours (MCTs), in major global markets, including the USA, Europe, and Australia. QBiotics has partnered with Virbac, a global animal health company, to distribute STELFONTA®.

Our wound healing drug candidate, EBC-1013, is a small molecule, which targets multiple pathways to accelerate healing, improving outcomes in chronic and acute wounds and burns. A first-in-human Phase I clinical trial in venous leg ulcers is open for recruitment. 

For more, head to: QBiotics.com or LinkedIn.