Proton-pump inhibitors and cancer therapy: a bad combination?

Some retrospective studies suggested that combination of PPIs with immuno-chemotherapies, is associated with worse outcomes. What's new on this issue?

PPIs and immuno(chemo)therapies: an overview

Do PPIs interfere with cancer therapies?

In recent years, retrospective studies have shown that the simultaneous administration of proton-pump inhibitors and immunomodulatory cancer therapies can be an unfavourable combination. In particular, the administration of ICIs can lead to worse outcomes.

The reason for this is most likely that PPIs change the intestinal flora, and thus also influence the patient's microbiome. This change in the bacterial makeup of the gut may be associated with an altered response to immunotherapies.

Many studies are tackling the issue

The topic is currently the focus of many researchers. For example, there are several new studies on the topic of interference between drugs in oncological practice. Lung cancer is of particular interest here, as it is one of the most frequent causes of death in oncology patients.

Various research teams have in recent months investigated whether the combination of PPIs and ICIs is associated with negative outcomes.

Should PPIs and ICIs be avoided?

In general, the administration of PPIs is associated with shorter survival when monotherapy with ICIs is given at the same time. Interestingly, the negative effects of the stomach-protecting agents are put into perspective when ICI therapy is supplemented with chemotherapy. The data thus suggest that monotherapy with ICIs in combination with PPIs is rather unfavourable. Nevertheless, further studies on the topic are necessary.

Conclusion for medical practice

The concomitant administration of PPIs and ICIs may be associated with shorter survival. However, if chemotherapy is given in addition to immunotherapy, the negative outcomes of proton-pump inhibitors are largely relativised. Further studies are needed to gain more clarity.