Novartis, a Switzerland-based healthcare company, has unveiled what promises to be a ground-breaking new drug for some leukaemia patients. The standard cancer treatments include radiation, chemotherapy and surgery, but some new options have entered the market in recent years. Some drugs target specific molecular changes, like Imatinib Mesylate, while others, like Novartis’ drug, target the immune system.
Called “a living drug,” Novartis’ Kymriah uses CAR T-cell therapy to genetically alter a patient’s own immune cells so they can destroy tumor cells just like viruses. After the success of smaller trials, Novartis funded a larger trial, and the majority of patients treated with CAR T-cell therapy went into remission. Based on these results, Food and Drug Administration approved the drug tisagenlecleucel (Kymriah) in August for childhood acute lymphocytic leukaemia (ALL).
How does CAR T-cell therapy work?
T cells, or T lymphocytes, are types of white blood cells located in the immune system. The many different kinds of T cells can be grouped into two main categories: Killer T-cells destroy infected or cancerous cells and helper T-cells create immune responses, like some allergic reactions. Each kind of cell has a specific antigen, or protein. T cells have receptors to identify these antigens, which is how they kill malignant cells.
To create T-cells that fight cancer, researchers draw blood from patients and send them to Novartis scientists. They then separate T-cells from other blood cells and use a disarmed virus (a virus that doesn’t cause the patient to get sick) to genetically engineer the cells to recognize cancer cells. Once doctors reintroduce the cells into a patient’s body, they multiply and destroy cancer like regular immune cells.
What does this mean for patients?
Though ALL’s five-year survival rate is about 85 percent, it’s one of the leading causes of death among childhood cancers. For many patients who relapse after intensive chemotherapy or a stem cell transplant, treatment options were slim, until now.
Though the treatment is giving options where there used to be none, there are downsides of the drug. It can cause some significant side effects. Cytokine-release syndrome (CRS), for example, causes intense immune reactions that can lead to high fevers and drops in blood pressure. Researchers have also seen patients experiencing swelling in the brain and instances of the altered T-cells killing other immune cells.
Despite the side effects, physicians are hopeful for the potential of the treatment. “Our data provide the first true glimpse of the potential of this approach in patients with aggressive lymphomas, who, until this point, were virtually untreatable,” said the lead investigator for one of the trials, James Kochenderfer, MD, of the National Cancer Institute.
Continuing the innovation
The FDA only approved CAR T-cell treatment for children and young adults (up to the age of 25) with ALL. However, it also shows promise in treating non-Hodgkin lymphomas and is being tested for other diseases as well. While there is some skepticism that CAR T cells will have the same success in solid tumors, researchers are working to identify the correct antigens. Other companies are also testing improvements of the current CAR T-cell therapy. Researchers are looking into ways to create CAR T-cells inside the body, rather than in a lab, to refine therapy so side effects are less serious, to identify and administer treatment in high-risk patients before relapse and more.
“In the next few years, I think we’re going to see dramatic progress and push the boundaries of what many people thought was possible with these adaptive cell transfer-based treatments,” said chief of the Surgery Branch in NCI’s Center for Cancer Research, Steven Rosenberg, MD, PhD, an immunotherapy pioneer whose lab was the first to report successful cancer treatment with CAR T-cells.