For more than a decade, the story of cancer immunotherapy has been written around the blockbuster PD-1 and CTLA-4 inhibitors that turned immune checkpoints into household names for oncologists and investors alike. Yet the limits of these drugs are becoming clearer — many patients relapse, others never respond, and resistance mechanisms are mounting.
Enter VISTA, a lesser-known checkpoint that has quietly gained traction as one of the most promising new targets in oncology. Short for “V-domain Ig suppressor of T cell activation,” VISTA is a protein found primarily on myeloid cells and some T cells, where it acts as a powerful brake on the immune system. Its role in maintaining an immunosuppressive tumour microenvironment has made it a prime candidate for next-generation therapies designed to boost immune attack against cancer.
Why VISTA matters now
Preclinical research has shown that blocking VISTA can reinvigorate exhausted T cells and enhance anti-tumour responses, particularly when used alongside PD-1 or CTLA-4 inhibitors. Scientists are increasingly linking VISTA expression to resistance mechanisms that blunt today’s frontline immunotherapies, suggesting that targeting it could extend the reach of checkpoint blockade into patient groups currently left behind.
A recent study from the Cleveland Clinic found VISTA directly interferes with T-cell activity during immunotherapy, underscoring its role in immune evasion. Meanwhile, radiotherapy experiments at Stanford University demonstrated that VISTA-positive myeloid cells can dampen responses to treatment, but that VISTA blockade reversed the effect and prolonged survival in preclinical models.
Together, these findings highlight a broader momentum in immuno-oncology: researchers are moving beyond the “first wave” of checkpoint inhibitors to focus on more nuanced regulators of the tumour microenvironment. VISTA is at the forefront of that shift — and one Australian company has placed itself firmly in the middle of the action.
Percheron’s pivot to immuno-oncology
Percheron Therapeutics Ltd (ASX:PER, OTC:PERCF) made headlines in June when it secured global rights to HMBD-002, a Phase II-ready anti-VISTA monoclonal antibody developed by Hummingbird Bioscience. The deal marked a strategic pivot for the Melbourne-based biotech, which has shifted from a rare-disease focus into mainstream oncology.
Under the terms, Percheron paid an upfront US$3 million (A$4.6 million) and could hand over as much as US$287 million (A$443 million) in development and commercialisation milestones, plus royalties. For a small-cap biotech, that represents a transformative commitment — but also a clear statement of intent to move quickly into the clinic.
HMBD-002 has already completed a US Phase I trial, showing a favourable safety profile and early signals of pharmacological activity. Full results are expected later this year, paving the way for Percheron to finalise plans for Phase II studies in 2026.
Promising data in tough cancers
Preclinical data around HMBD-002 has been compelling. In triple-negative breast cancer, one of the most aggressive and treatment-resistant tumour types, the antibody significantly suppressed tumour growth in models with high VISTA expression.
In preclinical models, HMBD‑002 significantly blocked tumour growth as a monotherapy, hinting at mechanisms beyond traditional immune modulation — a point Percheron has emphasised as a potential differentiator from frontline therapies like Keytruda.
Read more: Percheron shares new preclinical data on HMBD-002 in triple-negative breast cancer
Further studies in head and neck cancer — the research conducted in collaboration with Stanford University — found that combining HMBD-002 with radiotherapy enhanced treatment effects and prolonged survival in mice.
The findings suggest the drug could have broad utility in combination settings, where many see the future of immunotherapy heading.
Analyst endorsement and valuation upside
Pitt Street Research analysts described HMBD-002 as the most advanced VISTA-targeting antibody in development, with the potential to address PD-1 resistance and open new treatment avenues. Their modelling values the program at between US$162 million and US$329 million in a base case, with upside to nearly US$470 million in a bullish scenario.
They also pointed to several near-term catalysts that could sharpen investor attention: publication of Phase I results, Phase II trial design, potential orphan drug designations, and the possibility of sub-licensing deals in specific territories.
Read more: Pitt Street Research sees upside in Percheron Therapeutics as it pivots to immuno-oncology
Positioning in a changing landscape
Percheron’s move into VISTA comes at a time when the oncology field is eager for fresh approaches. With PD-1 inhibitors generating more than US$40 billion annually but leaving large patient populations underserved, the push to identify new checkpoints has intensified. VISTA, with its unique role in suppressing early T-cell activation and driving therapy resistance, is one of the leading contenders to expand the arsenal.
For Percheron, the bet on HMBD-002 could redefine its trajectory. Moving from early-stage projects into a mid-clinical, globally competitive program brings risk — but also the potential for outsize rewards if VISTA blockade lives up to its promise.
The bigger picture
Immuno-oncology’s first chapter was defined by PD-1 and CTLA-4. The next may well belong to checkpoints like VISTA, where deeper understanding of tumour biology is yielding new therapeutic entry points. If that proves true, Percheron’s HMBD-002 could become one of the flagbearers for a new generation of treatments designed to overcome resistance and widen the reach of immunotherapy.
For investors, the company’s recent pivot is both a test case and an opportunity: a chance to watch whether targeting the immune system’s subtler levers can generate not only clinical breakthroughs, but also meaningful shareholder value.