A pilot proof-of-concept study by life sciences company Invion (ASX: IVX) has shown a complete regression of triple negative breast cancer (TNBC) in vivo following treatment with lead active pharmaceutical ingredient INV043.
Conducted by Invion research partner Hudson Institute of Medical Research, the study used immuno-competent mice implanted with TNBC, establishing solid tumours in the mammary fat pads which rapidly metastasised.
Three control groups comprised one that was left untreated, while the other two were administered with light or with INV043 alone.
In these groups, the tumours enlarged rapidly and reached their endpoint (more than 100 square millimetres in size) by Day 19.
Autopsies showed the cancer had spread to the lungs and the abdominal fat pad.
Control animals which received only INV043 or light treatment showed similar progression.
The treatment group with established tumours had INV043 injected intratumorally and were then subject to Photosoft therapy.
No anaesthesia was required and no adverse effects were observed.
The treatment was repeated nine days later.
Photosoft using INV043 was shown to generate a complete tumour regression with no recurrence of disease.
There was also no apparent scarring or other indication of prior tumour presence, and no evidence of either primary tumour or metastatic spread at autopsy.
The mice which achieved remission were re-challenged with a second TNBC implant at a new site but no new tumours could be established, suggesting a development of protective immunity following INV043 treatment.
Protective immunity is considered a key requirement to maintaining long-term remission.
Invion said INV043 had performed “exceptionally well” in the study and showed promise as a potential treatment for TNBC and a range of other difficult-to-treat cancers.
“[Our drug] completely regressed the primary tumour, and appears to have prevented the cancer from returning or spreading to other parts of the body … this sets it apart from other cancer treatments,” it said.
Hudson Institute will conduct further proof-of-concept studies including a larger TNBC study (primary tumour model) and a secondary study investigating the potential of INV043 to treat metastatic disease.
Each study will include opportunities to explore potential synergies with other cancer therapies.
TNBC is an aggressive and metastatic tumour type which is innately resistant to most chemotherapies, is difficult to treat and has high rates of mortality.