A new way of cancer treatment that harnesses and augments the abilities of the body’s own immune system has been found effective in improving survival rates and quality of life of lung cancer patients.
Dr. Daniel Chan, senior consultant medical oncologist at the Icon SOC Mount Elizabeth Medical Centre in Singapore, was one of the doctors who spoke at a recently held cancer treatment symposium that focused on immunotherapy.
Dr. Chan has treated a number of Singaporean and Southeast Asian patients using immunotherapy, applied through an immune checkpoint blocker called pembrolizumab.
“In 2014, when pembrolizumab was first approved for use in the United States, there was a lot of skepticism in the medical community that something as gentle as immunotherapy could work for something as aggressive as cancer,” said Dr. Chan.
He continued, “But from recent clinical trials we now know that it could be effective in the right circumstances.”
As a medical oncologist, Dr. Chan is especially concerned with cancer drug efficacy and safety, because lung cancer specifically is often diagnosed in its late stages and usually at a time when the patient is already in a frail state.
This makes the cancer harder to control, not only because it has already spread to other parts of the body, but also because the patient is often already beset with other health conditions that make their body more vulnerable to the rigors of conventional treatments, as in the case with chemotherapy.
“Before immunotherapy came around, the median survival of stage 4 lung cancer patients was just a little over a year. And in that remaining time, the patients endured repeated chemotherapy, so their quality of life was very poor,” said Dr. Chan.
In contrast, studies on immunotherapy where pembrolizumab was used have shown median survival rates of 2.5 years and above. As the observation period for immunotherapy patients continues, researchers are finding that many patients are staying alive longer than they were expected to, had they undergone chemotherapy instead.
“The most common side effects I see with pembrolizumab are rash, fatigue, and thyroid gland dysfunction,” said Dr. Chan.
In lung cancer chemotherapy, on the other hand, patients normally experience nausea, vomiting, hair loss, low blood count, and a host of other adverse effects from their treatment.
“Pembrolizumab infusion is also fast. You get it once every three weeks and it takes half an hour, unlike chemotherapy for lung cancer, which includes hydration and antiemetics—this takes easily three to four hours,” shared the Singaporean health expert.
Dr. Chan added, “Even in this day and age, people are still very resistant to chemotherapy because they hear it will weaken the immune system—and thus weaken the body. They think it is the chemotherapy—not the cancer—that will kill them. So when they get immunotherapy instead and see how it is more tolerable for the body, it is really a load off their minds.”
However, not all lung cancer patients are ideal for an immunotherapy treatment. Researchers have found that non-small cell lung cancer or NSCLC patients who respond best to pembrolizumab are those whose cells show a high level of a protein biomarker on the cancer cell surface called PD-L1.
Therefore, PD-L1 testing proves to be an invaluable screening tool to determine the chances of treatment success with each individual NSCLC patient on pembrolizumab. It also improves the cost-effectiveness of the drug.
At present, immunotherapy treatment costs are not yet covered by PhilHealth, but are subsidized up to 55 percent by the Philippine Charity Sweepstakes Office upon confirmation that the patient is qualified for health-care subsidy.
In the Philippines, pembrolizumab is already approved for the treatment of non-small cell lung cancer, head and neck squamous cell carcinoma, melanoma, gastric cancer, urothelial cancer, and classic Hodgkin lymphoma. Potential patients may consult their medical oncologist to learn more about immunotherapy.