Immunotherapy: Innovative way to kill a killer

The concept of immunotherapy has been around for a long time. A century ago, a physician known as William Coley noted that some patients, when infected with a bacterium, appeared to fight off their cancers. The theory behind immunotherapy is that your immune system already knows how to fight cancer. Just as your body is able to identify, label, and mount an immune response against bacteria and viruses that invade it, cancer cells may also be tagged as abnormal and eliminated by the immune system. However, cancers sometimes figure out how to outsmart the immune system and protect themselves; this is the basis of immunotherapy, it actually helps in boosting the body’s immune system in identifying and targeting the cancer cells.

While there are many different types of immune cells and molecular pathways that result in the removal of cancer cells, the "big guns" in fighting cancer cells are the T-cells (T lymphocytes) and natural killer cells (NK cells). Immunotherapy works directly or indirectly to enhance the activity of these cells which in turn work against the cancer cells.

Immunotherapy has been used in cancer treatment since previous time with the use of BCG vaccine as part of local therapy for urinary bladder cancer. Different types of immunotherapy work in different ways. Some immunotherapy treatments help the immune system stop or slow the growth of cancer cells. Others help the immune system destroy cancer cells or stop the cancer from spreading to other parts of the body. Immunotherapy treatments can be used alone or combined with other cancer treatments. These treatments include non-specific immunotherapies like Interferon and Interleukins, which have been used for treatment of multiple cancers like urinary bladder cancer, multiple myeloma, blood cancers and others.

The other types of immunotherapies that are now being used commonly in multiple tumor sites are the immune checkpoint inhibitors (ICI). This all started with its use in disease like Malignant Melanoma in the early 2000 with Ipilumumab that targeted the CTLA-4 pathway. Later on other ICI like Pembrolizumab and Nivolumab which are called the PD-1 Inhibitors evolved and were used in Lung tumors and other sites. Now recently other agents came which were the PDL-1 inhibitors of which Atezolizumab is the prototype. These were initially being used in metastatic disease but their indication has been proven in curative cases as well. In-fact Immune checkpoint inhibitors are the only Immunotherapies being used extensively for treating cancers. Other types of immunotherapies include the Oncolytic Virus therapy and the CAR-T therapy, which are approved in some tumors.

Immunotherapy is being developed extensively and within the next decade or so, every patient afflicted by cancer will be treated with medicines that heighten their immune responses, in conjunction with traditional medicine if required. But there is still very little data on the efficacy and tolerability of these new drugs on the Pakistani population as the immune system is greatly shaped by our diet and the microbes that therefore live in our intestines. The goal of employing more immune system-empowering drugs is to make cancers less deadly, and perhaps even allow for cancer lesions to be controlled entirely by the patient’s own immune system by making them chronic instead of fatal. Compared to traditional forms of cancer medicine like chemotherapy and radiotherapy, immunotherapy produces much fewer acute side effects. But still immunotherapy has its own immune related side effects that are managed commonly be steroids.

Checkpoint blockade therapies are especially useful in treating head and neck as well as lung cancers because smokers have mutations on tumour cells. Other than lung, melanoma, lymphomas and solid tumors can be treated as well. These therapies have become the front line in treating Liver cancers as well. Recently the ESMO (European Society for Medical Oncology) had reported the first modest immunotherapy success against triple negative breast cancer, a horribly aggressive disease found primarily in younger women, which has stubbornly resisted previous treatment options.

The Oncology department at Dr. Ziauddin Hospital, North Nazimabad was the 1^st Private Oncology Centre in Karachi and had started functioning in 1997. We had later established our state of the art Cancer Centre and Radiotherapy department in 2014 after which we had started all the modern treatments like Immunotherapy and Radiation treatments like 3D-CRT and IMRT. Immunotherapy like Nivolumab and multiple targeted therapies for various indications like Lung Cancer, Kidney Cancer, Head and Neck Cancer; Uterine Sarcoma and Hodgkin’s lymphoma had been used since then. Furthermore after the approving indication of Immunotherapy in Triple negative breast Cancer we also have started Atezolizumab in these patients. We have immense pleasure in informing that 2 of our patients who were continued on Immunotherapy for 2 years were declared free of disease (Complete Clinical Response) on response evaluation with PET imaging. Currently we are also receiving patients with specific requirement of Immunotherapy and we cater around 4-5 patients of immunotherapy per month along with all other targeted therapies and chemotherapies.

Dr. Shabbir Hussain

Consultant Oncologist

Dr. Ziauddin Hospital

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