There is new evidence that taking certain common drugs could negatively impact mesothelioma survival after immunotherapy.
The microbiome interacts with the immune system. Ohio State University researchers say some medicines disrupt the microbiome. This can threaten the effectiveness of cancer immunotherapy.
The Microbiome and Immunity
The microbiome is the collection of bacteria that live in the intestinal tract. Every mesothelioma patient’s microbiome is unique. Scientists are just beginning to understand the importance of the microbiome in human health.
At first glance, there might not seem to be a direct correlation between the microbiome and mesothelioma survival after immunotherapy. But scientists know that there is a relationship between the microbiome and immunity.
The aim of the new study was to understand how that relationship might impact cancer immunotherapy.
The Microbiome Affects Mesothelioma Survival After Immunotherapy
Immunotherapy is a cancer treatment that uses the power of the immune system to fight cancer. It is an important area of mesothelioma research.
Immune checkpoint inhibitors are one type of immunotherapy. Pembrolizumab (Keytruda) is an example of an ICI. Studies show some patients experience longer mesothelioma survival after immunotherapy with Keytruda.
But not all mesothelioma patients respond well to ICIs. The new study suggests this could have to do with their microbiome. “There is growing evidence that the microbiome can significantly influence immune checkpoint inhibitor therapy,” says first author Daniel Spakowicz, PhD.
In the study, cancer patients who took medications that disrupted their microbiome had worse outcomes. If the findings are right, it could lead to a microbiome test for cancer patients. The test could help identify patients with the best odds of mesothelioma survival after immunotherapy.
Timing of Medications is Important
The Ohio State team analyzed data from 690 patients with advanced cancer. The patients received immunotherapy with ICIs between 2011 and 2017. The team made a model showing how some common drugs relate to cancer treatment outcomes.
They focused on medications known to affect the microbiome. They included
- Non-steroidal anti-inflammatory drugs (NSAIDs) like Advil, Motrin and aspirin
- Histamine blockers (antacids) like Tagamet and Zantac
- Corticosteroids like prednisone and Celestone
- Antibiotics like amoxicillin and Cephalexin
The patients who took antibiotics or corticosteroids within 28 days of ICI therapy had reduced survival after immunotherapy. Beta lactam antibiotics like penicillin derivatives had the strongest link to survival.
Antacids and NSAIDs negatively affected survival in specific cancers. The NSAIDs were especially detrimental in people with non-small cell lung cancer. Pleural mesothelioma and non-small cell lung cancer share many similarities. This suggests that NSAIDs might also negatively impact mesothelioma survival after immunotherapy.
Spakowicz, D, et al, “Inferring the role of the microbiome on survival in patients treated with immune checkpoint inhibitors: causal modeling, timing, and classes of concomitant medications”, May 6, 2020, BMC Cancer, https://bmccancer.biomedcentral.com/articles/10.1186/s12885-020-06882-6
“Microbiome Might Reveal Whether Immune Therapy Can Benefit a Patient, Study Shows”, July 14, 2020, Ohio State University Comprehensive Cancer Center, https://cancer.osu.edu/news/microbiome-might-reveal-whether-immune-therapy-can-benefit-a-patient-study-shows