In the last few decades, scientists have finally learned to use the immune system to successfully treat cancer. Images for Representatives. | Photo Credit: Freepik
In the last few decades, scientists have finally learned to use the immune system to successfully treat cancer. Although doctors often use immunotherapy drugs, other types of treatment use the patient’s own cells to treat the cancer itself.
Car-T therapy, short for “chimeric antigen receptor T cells”, is a cutting-edge treatment that reprograms the patient’s immune cells to fight cancer. This innovative approach involves taking T-cells, a type of white blood cell that plays an important role in the immune system, from patients and modifying them in the laboratory to better recognize and attack cancer cells.
These enhanced T-cells are then multiplied and put back into the patient, where they seek out and destroy cancer cells. A lot of data shows that in lymphoma, a type of cancer that is difficult to treat, patients can do well.
In November 2023, the US Food and Drug Administration (FDA) announced an investigation into this celebrated cancer treatment. They are looking into whether Car-T therapy can cause new cancers in some patients who have already undergone the treatment. This is a significant concern given the therapy’s reputation as a revolutionary cancer-fighting strategy.
First, the FDA mentioned that it has experienced 20 cases in which patients developed new immune cell cancers, such as lymphoma or leukemia, which is a type of blood cell cancer, after receiving Car-T therapy. This raises questions about who these patients are, how many such cases there are and what other treatments they could have received before Car-T therapy.
As of March 2024, the FDA has documented 33 such cases among 30,000 patients treated. Consequently, all Car-T therapies now carry a boxed warning about the potential risk of developing secondary cancers. The European Medicines Agency has also launched its own investigation into the matter.
Despite these concerns, it is still unclear whether the new cancers are caused directly by Car-T cells or whether other factors are involved. It is also important to note that this cancer is very rare – according to the data published this month.
Many cancer treatments come with the risk of secondary cancers and, of course, the cancer returning. And patients receiving Car-T therapy often have several other treatments that may also increase their risk. Researchers are now trying to determine if Car-T therapy is a contributing factor or the main cause of these new cancers.
Car-T therapy was initially used for patients who had no other treatment options, but has been approved as a second-line treatment for certain types of blood cancers, such as lymphoma and multiple myeloma. Scientists are also exploring the potential to treat solid tumors including brain cancer, autoimmune diseases, aging, HIV and other conditions.
The process of making Car-T cells involves using viruses to insert new genetic material into T cells. These viruses, called retroviruses, are engineered to carry chimeric antigen receptor genes (Cars) into T cells.
Massive benefits
When these retroviruses are modified to be safe, there is always the risk that the new genetic material can interfere with other important genes and cause cancer – a phenomenon known as “insertion mutagenesis”. This means that new genetic material is added to the cell.
This risk is not new. About 20 years ago, gene therapy treatment for severe combined immunodeficiency syndrome using the same retrovirus caused leukemia in some patients. As a result, scientists have worked to improve the safety of this viral vector. The FDA now requires extensive testing to ensure that the virus used in Car-T therapy cannot replicate and cause harm.
Despite these findings, the most important thing to emphasize is that secondary cancers remain rare and that cell therapy can be of great benefit to those who are seriously ill.
A recent review of patients treated with Car-T therapy at multiple centers found that only a small percentage developed secondary cancers, and most were not of a type directly related to Car-T treatment. This suggests that there is a risk, but it is relatively low compared to the immediate threat posed by the cancer present in the patient.
Medical professionals now inform patients of the potential but rare risk of secondary cancers when discussing Car-T therapy. For most patients, especially those with advanced cancer, the potential benefits of Car-T therapy outweigh the risks.
As noted, Car-T therapy is also being investigated for other applications beyond cancer. For example, it has shown promise in treating autoimmune diseases such as lupus and even preventing rejection of organ transplants. The potential use of Car-T cells continues to expand, offering hope for the treatment of various diseases.
Ultimately, while the risk of secondary cancer from Car-T therapy is a serious consideration, the benefits for many patients are significant and outweigh this small risk. Research will continue to refine these treatments and improve their safety.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
