Stanford University researchers have demonstrated that injecting tiny amounts of two immune-stimulating agents directly into tumours in mice can eliminate all traces of cancer, in what could be a ground-breaking new approach for treating the deadly disease.
The scientists say this method is a fast and relatively inexpensive cancer therapy, with minimal risk of damaging side effects.
In a new study, published in the journal Science Translational Medicine, the Stanford team found that the approach was effective for many types of cancer and was even capable of removing traces of the disease once it had metastasised - or spread.
"When we use these two agents together, we see the elimination of tumours all over the body," said Ronald Levy, senior author of the study. "This approach bypasses the need to identify tumour-specific immune targets and doesn't require wholesale activation of the immune system or customisation of a patient's immune cells."
These immune-stimulating agents – one of which is already approved for use in humans – come under the field of cancer immunotherapy – a treatment approach which focuses on harnessing the body's own immune system to combat the disease.
Some of these therapies work by stimulating the immune system throughout the entire body, while others, such as CAR T-cell therapy, involve removing immune cells from the patient and bio-engineering them to attack tumour cells once reintroduced.
Many of these therapies have been very successful in removing cancer, however, they do have drawbacks ranging from strong side effects to high cost or lengthy treatment cycles.
But the hope is that the new approach will mitigate these drawbacks.
"Our approach uses a one-time application of very small amounts of two agents to stimulate the immune cells only within the tumour itself. In the mice, we saw amazing, body-wide effects, including the elimination of tumours all over the animal."
In other words, once the stimulated immune cells had treated the original tumour, they then spread around the body to find and destroy tumours with an identical make-up.
In mice implanted with multiple lymphoma tumours, injecting one tumour with the treatment totally cured 87 out of 90 animals. The cancer did recur in three of the mice, although it regressed again after a second treatment. These results were replicated in mice with breast, colon and melanoma tumours.
Clinical trials in humans involving 15 patients with lymphoma are set to begin in the near future. If these are successful, the treatment may, one day, be applied prior to surgical removal of tumours as a way to prevent recurrence.