Doctors are cautiously hopeful about a new multiple sclerosis therapy after finding that injecting stem cells into patients’ brains was safe and potentially protective against further damage from the disease.
The small, early stage trial was only able to assess whether injecting cells directly into the brain was well tolerated by patients, but in tests carried out in the year after treatment, researchers found hints that the cells may have a long-lasting, beneficial impact.
“We don’t know yet whether this is the beginning of a fantastic journey or not, but the results are very strong and very consistent,” said Prof Stefano Pluchino at the University of Cambridge.
More than 2 million people worldwide live with multiple sclerosis. While most existing drugs target the early, relapsing remitting phase of the disease, two-thirds of patients still move on to the secondary, progressive and increasingly debilitating stage within 30 years of diagnosis.
The disease occurs when the body’s immune system attacks the protective myelin sheaths that wrap around nerve fibres, causing damage that disrupts how electric signals are beamed around the nervous system.
For the first in-human trial of the therapy, researchers injected between 5m and 24m neural stem cells directly into the brains of 15 patients with secondary progressive MS. Rather than rebuilding damaged tissues, the stem cells are thought to reduce the inflammation that drives the disease.
Some patients on the trial experienced side-effects, with one developing a tremor and another steroid-induced psychosis, but all recovered with treatment.
Tests on the patients over the following year found that none reported any worsening symptoms or increased disability, though most were using wheelchairs before the study and may not have deteriorated anyway. Brain scans revealed that patients who received higher doses of stem cells experienced less brain shrinkage, perhaps because the stem cells were dampening inflammation.
What intrigued the scientists most were tests on the cerebrospinal fluid that bathes the brain and spinal cord. These revealed that patients who received more stem cells had higher levels of compounds called carnitines, which are thought to protect neurons from damage. “What does it mean? I have no idea. But it is incredibly exciting,” said Pluchino. Details are published in Cell Stem Cell.
The researchers are now keen to run a larger trial to confirm whether or not the injections are changing the course of the disease. One factor they need to rule out is any effect from the immunosuppressive drugs patients took to prevent rejection of the stem cells.
Prof Paolo Muraro, an expert in neuroimmunology at Imperial College London, who was not involved in the study, said the trial set a benchmark for the manufacture and quality control of the cell-based drug. Further challenges remain, however. One is scaling up the therapy and making it affordable for large trials to investigate how effective the treatment is. “It is a long journey for hope, but certainly a worthy one,” Muraro said.
Caitlin Astbury at the MS Society said it was “a really exciting study” that built on previous research funded by charity. “These results show that special stem cells injected into the brain were safe and well-tolerated by people with secondary progressive MS,” she said. “They also suggest this treatment approach might even stabilise disability progression. We’ve known for some time that this method has the potential to help protect the brain from progression in MS.
“This was a very small, early-stage study and we need further clinical trials to find out if this treatment has a beneficial effect on the condition. But this is an encouraging step towards a new way of treating some people with MS.”
