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CAR T cells

CAR T cells

 Chimeric antigen receptor (CAR) T cell therapy is a new form of cancer therapy and is showing a lot of promise.

T cells are a part of body’s immune system. They are a type of white blood cells. T cells have proteins on their surface which act as receptors. Any foreign substance that enter the body like bacteria and virus also have proteins on their surface. Whenever T cell receptors come across the protein antigen of the foreign substance, the latch onto it and destroy the foreign substance. But Not every T cell receptor can bind to every protein antigen since both the receptors as well as antigen on foreign bodies are differently shaped. Only those that fit their receptors can be destroyed.

This forms the basis of CAR T cell therapy in cancer therapy. Since cancer cells also have antigens and can bind to T cells receptors but it is rarely a perfect fit, scientists have developed a novel method of help the T cells bind more accurately to a particular type of cancer cell.

The process:

  1. Firstly patients are evaluated thoroughly via a series of tests to assess if CAR T cell therapy would be useful in their case or not

  2. Secondly blood is drawn patients into a machine where white blood cells are removed along with the T cells and remaining blood is sent back into the patients body.

  3.  Next, T cells are separated from the rest of the white cells. They are sent to the laboratory where Chimeric antigen receptors CARs are added to the T cells, creating CAR T cells which can recognize antigen on the targeted tumor or cancerous cells.

  4. These reengineered T cells are then allowed to multiply in the lab until there are millions of them. This process can takes weeks.

  5. These millions of CAR T cells are then frozen and sent back to the hospital to be infused back into the patient. This is done via an IV line just like blood transfusion. Patients may receive chemotherapy prior to infusion of Car T cells, to prepare the immune system to receive the CAR T cells.

  6. Once inside the patients body, the CAR T cells start binding with the specific cancer cells against which they have receptors and once attached they increase in number and can destroy the cancer cells.

At present CAR T cells have been approved some few types of leukemias and lymphomas as well as multiple myelomas. However multiple clinical trails are underway across the world to check its effectiveness in various other types of cancers.

Side effects: Most of the complications are generally temporary and not quite severe, yet sometimes the therapy can cause some serious side effects.

The main amongst these are:

  1. Cytokine release syndrome CRS: When CAR T cells multiply, they release a huge amount of a chemical called cytokine which triggers an inflammatory condition called CRS. The symptoms of this can cause:

    High fever

    Chills

    Breathing difficulty Nausea, vomiting diarrhoea Fatigue

    Low blood pressure Rapid heartbeat Cardiac arrest

    Heart failure

    Multiple organ failure

  2.  There may also be neurological side effects such as Confusion

    Dizziness Delirium Seizures

    Loss of balance Trouble speaking

    Other symptoms also include allergic reaction during infusion Weakened immune system making one susceptible to other infections

This is why, the patient has to be kept in the hospital for a few weeks under strict observation and periodically evaluated for the next 2-3 months post treatment to check for side effects and treatment response.

In India, Tata memorial hospital (TMH) recently conducted the first CAR T cell therapy at the Bone Marrow Transplant unit at ACTREC in Mumbai in association with the Bioscience and Bioengineering (BSBE) department of IIT Bombay who designed and manufactured the CAR T cells.

A sum of Rs 19.15 crores has been approved by the National Biopharma Mission and BIRAC to the team to conduct the first- in-human phase-1/2 clinical trial of CAR T cells.

The clinical trials are being conducted byDr. Gaurav Narula, Professor of Paediatric Oncology and Health Sciences and his team from TMC (TATA MEMORIAL CENTER) mumbai. And the CAR T cells were manufactured by prof. Rahul Purwar of the BSBE department and his team from IIT-B.

Although this therapy is a great breakthrough in the field of cancer treatment, yet the cost is highly prohibitive and can run into crores of rupees per therapy.

The team of IIT-B along with the team from TMH are working relentlessly to make the trial a success and more importantly trying to make the treatment more affordable to the patients. And if the trials are successful, it could help save millions of lives. We at Specialty Surgical Oncology, are proud of these achievements and congratulate the team of TMH as well as IIT-B. Kudos to them!!!

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