Percheron Therapeutics Ltd (ASX:PER, OTC:PERCF) has released promising new preclinical data for its investigational cancer drug, HMBD-002, showing potential efficacy in the treatment of triple-negative breast cancer (TNBC), a particularly aggressive form of the disease.
The data, published in the peer-reviewed journal Cancer Research, highlights the drug’s activity in mouse models and its ability to block tumour growth in TNBC cases that express high levels of the VISTA immune checkpoint. It follows recent encouraging results for HMBD-002 in combination with radiotherapy for squamous cell cancer of the head and neck (SCCHN).
“This work provides important new insights into the relevance of VISTA in this very challenging and all-too-common cancer,” Percheron CEO Dr James Garner said of the TNBC investigation.
“There are few effective treatments for TNBC, and the disease represents one of the most significant areas of unmet need in cancer therapy.”
TNBC and the unmet clinical need
TNBC accounts for about 10-15% of all breast cancer cases, representing around 30,000 new diagnoses annually in the United States. Characterised by its resistance to existing therapies, TNBC remains a significant unmet medical need.
Research indicates that 25-30% of TNBC tumours express VISTA, a protein that plays a key role in immune suppression. This makes VISTA an attractive target for new treatments aimed at improving patient outcomes.
The preclinical studies led by Professor Josh Gruber at the University of Texas Southwestern Medical Center (UTSW) demonstrated that HMBD-002 effectively blocked tumour growth in a TNBC mouse model, with the results showing a statistically significant reduction in tumour size (p < 0.0001) in VISTA-expressing animals.
Potential differentiation from existing therapies
One key takeaway from the data is the potential dual mechanism of action of HMBD-002. Unlike conventional immunotherapies such as Keytruda® (pembrolizumab), which primarily target immune pathways, HMBD-002 may also modulate growth signals like EGFR, providing a potential edge in treating TNBC.
This novel mechanism could offer a unique treatment option for patients who have not responded to existing therapies.
In addition to its activity in TNBC, HMBD-002 has also shown promise in combination with radiotherapy for squamous cell carcinoma of the head and neck (SCCHN), with recent research from Stanford University further solidifying its potential as a broad-spectrum cancer therapy.
Path forward for HMBD-002
The new data opens the door to exploring HMBD-002 as a treatment for TNBC patients with high VISTA expression. Percheron is continuing to evaluate potential strategies for advancing the drug into phase II clinical trials, with additional data expected in Q4 CY2025.
The company will share final results from its phase I study of HMBD-002 in patients with advanced cancer in Q4 2025, providing further insight into its safety profile and potential for broader clinical application.
Percheron CEO Dr James Garner emphasised the importance of the results from the TNBC investigation.
“The data from Professor Gruber and colleagues provides a compelling indication that a VISTA inhibitor such as HMBD-002 may have a role to play in the future management of this condition,” he said.
As the company prepares to enter the next phase of clinical development, it will continue discussions with researchers, clinicians, and advisors to further refine its approach to TNBC and other oncology indications.