Therapeutic Interventions
One possible therapeutic intervention to restore the gut microbiome is fecal microbiota transplantation (FMT). In a phase 1 study presented by Dr. Poeck, FMT was effective in the treatment of 20 patients with melanoma with ICI in an advanced and treatment-naive stage. Seven days after the patients received FMT, the first cycle with anti-PD-1 immunotherapy was initiated, with a total administration of three to four cycles. After 12 weeks, most patients were in complete or partial remission, as evidenced on imaging.
However, FMT also carries some risks. Two cases of sepsis with multiresistant Escherichia coli occurred, as well as other serious infections. Since then, there has been an FDA condition for extended screening of the donor stool, said Dr. Poeck. Nevertheless, this intervention is promising. A search of the keywords “FMT in cancer/transplant setting” reveals 46 currently clinical studies on clinicaltrials.gov.
Nutritional Interventions
Dr. Poeck advises caution about over-the-counter products. These products usually contain only a few species, such as Lactobacillus and Bifidobacterium. “Over-the-counter probiotics can even delay the reconstitution of the microbiome after antibiotics,” said Dr. Poeck, according to a study. In some studies, the response rates were significantly lower after probiotic intake or led to controversial results, according to Dr. Poeck.
In contrast, Dr. Poeck said prebiotics (that is, a fiber-rich diet with indigestible carbohydrates) were promising. During digestion, prebiotics are split into short-chain fatty acids by bacterial enzymes and promote the growth of certain microbiota.
In this way, just 20 g of extremely fiber-rich food had a significant effect on PFS in 128 patients with melanoma undergoing anti-PD-1 immunotherapy. With 20 g of fiber-rich food per day, the PFS was stable over 60 months. The most significant benefit was observed in patients with a sufficient fiber intake who were not taking probiotics.
What to Recommend?
In summary, Dr. Poeck said that it is important to “budget” well, particularly with antibiotic administration, and to strive for calculated therapy with as narrow a spectrum as possible. For patients who experience complications such as cytokine release syndrome as a reaction to cell therapy, delaying the use of antibiotics is important. However, it is often difficult to differentiate this syndrome from neutropenic fever. The aim should be to avoid high-risk antibiotics, if clinically justifiable. Patients should avoid taking antibiotics for 30 days before starting immunotherapy.
Regarding nutritional interventions, Dr. Poeck referred to the recent Onkopedia recommendation for nutrition after cancer and the 10 nutritional rules of the German Nutrition Society. According to Dr. Poeck, the important aspects of these recommendations are a fiber-rich diet (> 20 g/d) from various plant products and avoiding artificial sweeteners and flavorings, as well as ultraprocessed (convenience) foods. In addition, meat should be consumed only in moderation, and as little processed meat as possible should be consumed. In addition, regular (aerobic and anaerobic) physical activity is important.
“Looking ahead into the future,” said Dr. Poeck, “we need a uniform and functional understanding and we need a randomized prediction for diagnosis.”
This article was translated from the Medscape German edition.
A version of this article appeared on Medscape.com.
