Hope For Lung Cancer Patients: Pembrolizumab Treatment Combo Raises Survival Odds To 70 Percent

A study published yesterday revealed that Merck's new immunotherapy drug Keytruda, or pembrolizumab, can greatly improve the chance of survival in people suffering from advanced non-small-cell lung cancer (NSCLC) — the most common type of lung cancer, which predominantly affects smokers, and the leading cause of cancer death.

The research, featured in the New England Journal of Medicine, investigated the differences between treating this type of lung cancer with chemotherapy alone versus adding pembrolizumab to the standard chemotherapy regimen.

According to the study, Merck's immunotherapy drug fared very well in a lung cancer trial for people with advanced non-squamous NSCLC, increasing survival rates to 69.2 percent when coupled with chemotherapy.

By comparison, patients receiving just the chemotherapy drug alone (platinum and pemetrexed, two standard chemotherapy agents that are used together) only had a 49.4 percent chance of survival after a year of treatment — 20 percent lower than the pembrolizumab-combination group.

"What it suggests is that chemotherapy alone is no longer a standard of care," said Dr. Leena Gandhi, who led the study.

"The addition of pembrolizumab to chemotherapy resulted in significantly higher rates of response and longer progression-free survival than chemotherapy alone," her team writes in their paper.

In the video below, Gandhi — who manages the Thoracic Medical Oncology Program at New York University Langone Health — explains that the combo treatment has proved "superior in terms of response, keeping people alive without progression of their cancer," and "improving the overall survival of patients with metastatic lung cancer" in comparison with chemotherapy alone.

In order to gauge the difference between the two types of treatment (pembrolizumab-combination versus chemotherapy), her team enrolled more than 600 patients from 16 different countries.

"The differences were not small," says Gandhi.

The study participants were divided into two groups: one group received only the chemotherapy drug, while the other was administered an additional 200 mg of pembrolizumab every three weeks, for the duration of four treatment cycles.

The results showed that pembrolizumab not only extends patients' lives but also doubles the progression-free survival period — from 4.9 months in the chemotherapy group to 8.8 months in the combination treatment group.

However, even though the combo treatment yielded impressive results, pembrolizumab only made a quarter of the patients enrolled in the study cancer free. In the majority of cases, the lung cancer returned after a year and a half of treatment, states NPR.

Yet even these odds are still considered a progress, says Gandhi.

"Chemotherapy (alone) doesn't do very much for non-small-cell lung cancer patients. It provides some, very modest, survival benefit that can be measured in months, not years."
Keytruda is part of a class of immunotherapy drugs known as checkpoint inhibitors, which act by stimulating the immune system to attack cancer cells. Aside from Keytruda, only three other checkpoint inhibitors have been approved by the American Food and Drug Administration (FDA) so far, reports the New York Times.

The advantage of Merck's immunotherapy drug is that it's already prescribed for the treatment of NSCLC — the FDA approved the Keytruda-chemotherapy last year, notes NBC News. Keytruda is also used to treat melanoma and Hodgkin lymphoma, as well as cancers of the stomach, head, neck, and bladder.

3D rendering of a pembrolizumab monoclonal antibody drug protein.
3D rendering of a pembrolizumab monoclonal antibody drug protein.

The downside of immunotherapy drugs is that they can come with serious side effects and that they generally work in about half the cases, points out the New York Times.

In the study conducted by Gandhi's team, an overwhelming majority of patients experienced side effects, among which nausea, anemia, and fatigue were the most frequent. The side effects were slightly more predominant in the Keytruda-chemo combination group — 99.8 percent, as opposed to 99 percent in the patients who only got chemotherapy.