Proton Pump Inhibitors reduce success of immunotherapy drugs

Proton Pump Inhibitors reduce success of immunotherapy drugs

A meta-analysis of 41 studies shows that taking Proton Pump Inhibitors such as Omeprazole, Lansoprazole and Pantoprazole leads to significantly worse outcomes in advanced cancer patients treated by immunotherapy in terms of Progression-Free Survival and Overall Survival.


Time and time again over the past 8 years, we have told you about these dreadful drugs. Yet alost all cancer patients are given them often for 6 months or more; and often for the wrong reasons (it will stop nausea). The prevent your chemo drugs causing Acid Reflux. That is the reason. 

If you have acid reflux anyway, you should be tested for Helicobacter pylori, a bacterial parasite in the stomach that can cause acid reflux. It is easily killed with the herb Goldenseal (400 mg) and Peptobismol for Bismuth.

You should only be taking small doses of a PPI, and even then just for the two or three days you have your chemo. No more. These drugs can cause lasting side-effects; and ruin the performance of certain cancer treatments such as PD-1 (Pembrolizumab) and PD-L1 drugs (Ipilimumab).

The fact is, you NEED stomach acid. It is essential for good digestion and proper nourishment from protein foods.  

Immunotherapy works better with a strong microbiome

We have told you about immunotherapy before. A good drug such as Pembrolizumab can have its effects ruined by taking antibiotics, or simultaneous chemotherapy. PD-1 drugs are long distance runners. Their effectiveness builds over a year or two and we have seen a good number of people beat their cancer where we have rebuilt the microbiome in advance of the patient taking the drug. After chemotherapy, this takes 12 weeks ideally.

Go to: How to make Immunotherapy work properly. 

We have also told you repeatedly about Proton Pump Inhibitors. These are dished out like sweets to children, and often to people who just don’t need them. I was offered one after a routine check by a doctor even though all my blood scores were perfect and I had no acid reflux. Just because of my age!

Proton Pump Inhibitors increase stomach cancer risk.

Taking a PPI just for a few weeks can increase risk of stomach cancer 3 fold; take it for a year and it’s a 5-fold increase; take it for 5 years and it’s an 8-fold increase.

Go To: Acid reflux pills cause up to 8 times the gastric cancer risk

Proton pump inhibitors can damage the microbiome.

A meta-analysis has shown that PPIs damage the diversity of the microbiome and deplete bacteria from the Ruminococcaceae and Lachnospiraceae families, which are crucial short-chain fatty acid-producers (2). 

The American Gastrointestinal Society agrees

I have been telling patients for five or more years that these drugs are dangerous. And the American Gastrointestinal Society agrees with me. They recently presented a review concluding that PPIs should only be taken in small doses and for no more than three days. 

Gastric cancer is the third leading cause of cancer death worldwide.

Go To: Why PPIs should be used at lower doses and for shorter periods

And now …

Proton Pump Inhibitors significantly damage immunotherapy performance.

In a meta-analysis of 41 studies, across several cancer types (for example, NSCLC) and for people have with or both PD-1 or PD-L1 immunotherapy, PPI significantly damaged the performance of the immunotherapies whether patients were already taking the PPI or were started in the 60 days before the immunotherapy (1).



  1. Do proton pump inhibitors alter the response to immune checkpoint inhibitors in cancer patients? A meta-analysis; Sebastia Lopes et al; Front. Immunol., 26 January 2023

  2. Meta-analysis of the effects of proton pump inhibitors on the human gut microbiota; Jiayi Zhang et al; BMC Microbiology volume 23, Article number: 171 (2023) 




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