Putting ‘killer cells’ to work against blood cancer
- Wits University
The work builds on the Wits Donald Gordon Medical Centre internationally accredited stem cell transplant programme.
While testing a promising new approach to treating blood cancer, the Wits Donald Gordom Medical Centre (WDGMC) also provides specialist training for South Africa’s next generation of haematologists.
Dr Jackie Thomson, clinical haematologist and stem cell transplant specialist at WDGMC, has spent much of her career building the healthcare systems needed to deliver advanced treatments for blood cancer.
The promise of killer cells
Thomson is pursuing research at WDGMC where an experimental therapy uses genetically engineered natural killer cells to seek out and destroy cancer cells.
The treatment targets CD19, a marker found on certain white blood cells, including those involved in some types of lymphoma (a type of blood cancer). The treatment builds on advances in CAR-T cell therapy, in which the patient’s own immune cells are collected, genetically modified to recognise cancer, and then returned to the body.
In conventional CAR-T treatment, the cells must be collected and manufactured for each individual patient. This takes time, requires specialised facilities and can be extremely expensive. Natural killer-cell therapy offers the possibility of an off-the-shelf product, manufactured from a common cell line and available to different patients without tailoring it to each individual.
“We believe this approach could eventually help reduce the cost of advanced cell therapies, making them accessible to more patients,” explains Thomson.
The centre began its trial in August 2024 and, according to Thomson, treated the first patient enrolled worldwide in that particular study. Around 15 patients have since received the experimental treatment.
The trial is in Phase 1, meaning its primary purpose is to assess safety rather than establish whether the treatment works. Even so, Thomson says the early findings have been encouraging.
“We found the product to be very safe. But we’ve got some really interesting results: some patients didn’t respond, and other patients responded incredibly well and went into remission very quickly.”
These are only preliminary observations and not evidence that the treatment is ready for routine clinical use. Further research will be needed to establish its effectiveness, longer-term safety and which patients are most likely to benefit.
Building on the success of transplantation
Despite advances in cell therapy, stem cell transplantation remains a potentially curative treatment for many patients with blood cancer. Thomson has seen the field change dramatically over the past 25 years.
“Twenty-five years ago, treating patients with blood cancer was very difficult,” she says. “But now, we have so many options for these patients. It really doesn’t feel like a death sentence anymore.”
Stem cell transplantation typically involves intensive chemotherapy, sometimes combined with radiotherapy, followed by an infusion of stem cells to restore healthy blood-cell production. When donor cells are used, they can also establish a new immune system capable of attacking remaining cancer cells.
The treatment carries risks. Chemotherapy and radiotherapy can cause serious complications, while donor immune cells may attack healthy tissues, causing graft-versus-host disease. Those same cells can also attack the cancer, producing what is known as the graft-versus-leukaemia effect.
The balance between these benefits and risks makes transplantation a highly specialised field, requiring careful patient selection, sophisticated laboratory support, and close clinical monitoring. “It’s a marriage of the laboratory, collection unit, and clinical unit,” says Thomson.
Even though immunotherapies are expanding treatment options, transplantation remains the best chance of a cure for some patients.
A centre built on international standards
Delivering these treatments safely requires far more than medical expertise alone. When Thomson established the stem cell transplant unit at WDGMC in 2019, one of her priorities was to build the infrastructure and quality systems needed to meet international accreditation standards.
The programme subsequently achieved accreditation from the Joint Accreditation Committee of ISCT and EBMT (JACIE), which assesses transplant services against internationally recognised standards for clinical care, cell collection, processing and quality management.
According to Thomson, the centre is particularly significant for its accredited paediatric transplant programme. “What makes this unit special is that we’re the first in Africa to achieve accreditation for paediatric stem cell transplantation,” she says. “This was a big gap in South Africa.”
The infrastructure also supports the centre’s research activities, enabling the careful handling of cell-based treatments and the monitoring and reporting required by clinical trials.
Training the next generation
WDGMC is also helping to address South Africa’s shortage of specialist expertise. Stem cell transplantation is a subspecialised field of haematology, requiring extensive additional clinical and laboratory training.
“Until recently, opportunities for hands-on training in transplantation were particularly limited in Johannesburg. That’s why it’s so important for us to have registrars rotating through the unit now,” says Thomson.
The centre also trains a fellow – an already qualified specialist gaining further expertise in transplantation. However, training more specialists is not the whole of the solution. “There’s a massive shortage of specialists, but they don’t have the posts for them,” Thomson says.
Thomson has spent much of her career working to improve healthcare systems, including when she held senior leadership roles at the South African National Blood Service. “My goal has always been to make a difference in healthcare,” she says.
She believes South Africa needs both effective primary healthcare, where illnesses can be identified early, and specialist centres capable of providing advanced treatment. “You need these lighthouses and beacons of hope, which stem cell transplantation and cell therapy really are.”