Emily, 7, was dying.
In fact she had 48 hours before her organs would start failing. She had been fighting leukemia (Acute Lymphoblastic Leukemia or ALL the most common leukemia among children) since she was 4 and unfortunately most traditional treatments have failed her.
She had relapsed for a second time during intensive chemotherapy treatment in February. Her parents had started looking for more radical options because they were beginning to feel desperate as traditional treatments could not help Emily remain in remission long enough to go through bone marrow transplant.
That is when they came across one of the craziest treatments to date at Cancer Center at The Children’s Hospital of Philadelphia, using modified HIV cells to go into a patient’s body to attack tumors from the inside with the goal to totally eradicate cancer within the patient.
Why are HIV cells dangerous to us?
Human immunodeficiency virus (HIV) is a virus that causes acquired immunodeficiency syndrome (AIDS), a condition in humans, in which progressive failure of immune system leads to death most often by opportunistic infections. Infection of HIV is spread by transfer of bodily fluids such as blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells.
HIV infects vital cells in the human immune system such as T helper cells, macrophages (cells that “eat” foreign particles in our body) and dendritic cells (makes antigens for other cells). HIV infection leads to lower levels of helper T cells through a number of mechanisms including: death of uninfected ‘bystander’ cells, direct viral killing of infected cells, and other immune system cells killing infected helper T cells. When the level of helper T cells decline below a critical level, cell mediated immunity is lost and the body becomes progressively more susceptible to opportunistic infections. This means that even a common cold can kill you because you don’t have the immune system to fight it off!
How this mind-blowing technology works:
This clinical trial, CTL019, uses immune cells taken from a patient’s own blood called T cells. These cells are genetically modified to express a protein which will recognize and bind to a target called CD19, which is found on cancerous B cells.
The video gives a quick insight into how this treatment works:
1. The cancerous immune cell, B Cells (like Bad cells), which are found in the immune system, becomes cancerous in certain leukemias and lymphomas such as ALL.
2. The healthy Immune cell, T cells are the workhorses of the immune system, recognizing and attacking invading disease cells
3. The Problem: Cancerous B cells fly under the radar of immune surveillance evading detection by T cells.
4. The solution: In this experimental treatment, T cells are collected from a patient, then reengineered in a lab to recognise and attach to a protein that is found only on the surface of B cells. After this reengineering, they are called chimeric antigen receptor T cells. The cells are put back into the patient where they disperse to find cancerous B cells. To do this, they used a modified HIV Virus, called lentivirus to carry special receptors into the T-cells. There is no risk of HIV infection from a lentivirus.
5. The result: As the reengineered cells multiply in the body, they attack to and kill the rapidly dividing, cancerous B cells. They remain in the body long after to continue fighting any new dangerous cancerous B cells.
What is amazing is that we are using HIV’s inherent ability to bind to cells within our body when they recognise specific receptors on that cell, and enter that cell, replicate within the cell and release the genetic material within it. It’s a genetic therapy factory packaged to do exactly what needs to be done. Because of the specificity of the receptors that can only be found on the tumor, these virus will infect and destroy the tumor only. Traditional treatments are still not cell specific and this why after treatments patients suffer from many side effects since their healthy cells can get affected too.
The potential for this kind of treatment is wide and we are only beginning to really explore this form of therapy; this is probably due to the fear attached to HIV and what could happen in case of possible of the worst case scenario which is that somehow inexplicably the patient undergoing treatment gets infected by it. This is why treatments for CTL019 has only been conducted on 2 children and about 10 adults for the treatment of leukemia. More testing and studies will have to be conducted, but the future for the treatments of cancer is exponential.
Currently, Emily had an additional drug used to treat rheumatoid arthritis to tackle a side-effect of the therapy and has been in remission since this treatment for more than seven months.
