Antibiotics, gut microbiome and heavier is better in relation to melanoma?????

I've been writing about the cooties in our guts - our microbiome - since 2015.  This post from 2018 includes lots of links to prior articles and reports:  Microbes again...and how they may be associated with improved response to anti-PD-1 for melanoma patients...and you might even laugh!!!

In June of this year, out of ASCO, the mircobiome was also addressed. I included a report on a couple of their articles here:  The first installment of this year's ASCO review.  That post included:

#6:  The "microbiome" craze is not exactly 'new' as it has taken over the universe! BUT!!!  How much is hype?  How much is real?  How can we drill down on the details?  How can we harness what we know to impact treatments such that patients benefit?  The next 3 posts address this topic.  Now, there's this:

A phase I/II study of live biotherapeutic MRx0518 in combination with pembrolizumab in patients who have progressed on prior anti-PD-1 therapy.  2019 ASCO.  Shubham, Imke, Amishi, et al. J Clin Oncol 37, 2019 (suppl; abstr TPS2670) 

Background: The gut microbiome has emerged as a new therapeutic target to augment the efficacy of immune checkpoint blockade. MRx0518 is a novel, gut microbiome-derived, oral live biotherapeutic, designed to induce a broad immunostimulatory response to re-engage PD-1 inhibitor activity. Preclinical studies showed that MRx0518 reduced tumour growth in models of kidney, lung and breast cancer. MRx0518 increased CD4 and CD8 T cell and NK cell infiltration into the tumour and decreased Tregs. Upregulation of tumour TLR5 was observed and linked to the bacterial flagellin moiety, which was shown to strongly induce NFκB, cytokine responses and IFNγ+ CD4 and CD8 T cells. The study, one of the first oncology trials conducted with live biotherapeutics, is a single center, open label, safety and preliminary efficacy study of MRx0518 in combination with pembrolizumab in patients with solid tumors who have progressed on PD-1 inhibitors. Methods: Trial consists of 2 parts. In Part A, 12 patients receive pembrolizumab 200 mg every 3 weeks plus 1 capsule (bid) of MRx0518 with a DLT period of 1 cycle (21 days). In Part B, up to 30 patients per cohort (NSCLC, Urothelial, Renal and Melanoma) will receive pembrolizumab 200 mg every 3 weeks plus 1 capsule (bid) of MRx0518 for up to 35 cycles or until disease progression per RECIST 1.1. The primary end points are safety and tolerability of MRx0518 in combination with pembrolizumab (Parts A and B) and clinical benefit of MRx0518 in combination with pembrolizumab (Part B). Secondary end points are objective response rate, duration of response, disease control rate, and progression-free survival. Exploratory end points include biomarkers of treatment effect, effect on microbiota and overall survival. Recruitment is ongoing. Clinical trial information: NCT03637803

Here, researchers are going to give the first 12 patients with solid tumors who have progressed on anti-PD-1, Pembro every 3 weeks along with a capsule of MRx0518, a "live biotherapeutic", taken by mouth, twice a day for one 21 day cycle.  In part b, the plan is that 30 patients could be given the same for up to 35 cycles or until disease progression.  My only concern here would be the fact that we've found that folks who took probiotics from a bottle did not do so well, while those that got their cooties from foods like Kefir, kimchi, yogurt, sauerkraut, etc. - did better.  If I were to consider participation in this study, I'd be asking my doc about that.

#7:  As I noted above, these last two reports are more along the lines of ~ "What once was old is new again!" I've been talking about the Cooties in our Gut since 2015, putting it all together in this post from 2018:  Microbes again...and how they may be associated with improved response to anti-PD-1 for melanoma patients...and you might even laugh!!!  Still, there is much we don't understand about how all this works.  Now, there's this:

Gut microbiota dependent anti-tumor immunity restricts melanoma growth in Rnf5^-/- mice.  Li, Tinoco, Elmen, et al.  Nat Commun. 2019 Apr 2.

Accumulating evidence points to an important role for the gut microbiome in anti-tumor immunity. Here, we show that altered intestinal microbiota contributes to anti-tumor immunity, limiting tumor expansion. Mice lacking the ubiquitin ligase RNF5 exhibit attenuated activation of the unfolded protein response (UPR) components, which coincides with increased expression of inflammasome components, recruitment and activation of dendritic cells and reduced expression of antimicrobial peptides in intestinal epithelial cells. Reduced UPR expression is also seen in murine and human melanoma tumor specimens that responded to immune checkpoint therapy. Co-housing of Rnf5^-/- and WT mice abolishes the anti-tumor immunity and tumor inhibition phenotype, whereas transfer of 11 bacterial strains, including B. rodentium, enriched in Rnf5^-/- mice, establishes anti-tumor immunity and restricts melanoma growth in germ-free WT mice. Altered UPR signaling, exemplified in Rnf5^-/- mice, coincides with altered gut microbiota composition and anti-tumor immunity to control melanoma growth.

So, a lot of fancy words to say that mice with a certain microbiome component (less UPR expression) responded better to immunotherapy.  Further, when those mice lived with mice whose gut initially did not possess those properties, researchers found that they too developed an altered gut flora and a greater ability to restrict the growth of melanoma.  Bottom line:  Live with somebody who has the right cooties!  (If you can figure out who exactly that is!!!)

#8:  Given the fact that a certain "microbiome" aids our responses to immunotherapy while a different one does not, it makes sense that antibiotics, which kill off bacteria that are trying to do us harm as well as those who may do a body good, could be problematic when trying to foster cooties that improve our response to immunotherapy.  Here are some earlier articles and explanations:

This from 2017:  Antibiotic use MAY decrease effectiveness of immunotherapy?????

And this from April of this year:  DECREASED progression free survival in melanoma patients treated with antibiotics prior to or at start of immunotherapy!!!!  In that study it was noted that, despite - "Small numbers. ..the 10 folks, from the 74 advanced melanoma peeps examined, who were given antibiotics within 30 days of their immunotherapy, had more resistance to treatment, a shorter length of progression free survival (2.4 vs 7.3 months) and overall survival was shorter at 10.7 months vs 18.3 months." 

Now, there's this:

Effect of antibiotic exposure in patients with metastatic melanoma treated with PD-1 inhibitor or CTLA-4 inhibitor or a combination of both.  2019 ASCO. Kapoor, Runnels, Boyce, et al.  J Clin Oncol 37, 2019 (suppl; abstr e14141)

Background: Pre clinical studies have demonstrated the effect of gut microbiome in the efficacy of immune check point inhibitors. The effect of antibiotic exposure to patients receiving PD-1/CTLA-4 inhibitor therapy has not been extensively studied, especially in metastatic melanoma. In this study, we demonstrate the effect of antibiotic exposure to metastatic melanoma patients receiving PD-1/CTLA-4 inhibitor therapy. Methods: We performed aretrospective analysis of 108 patients with stage 4 metastatic melanoma who received immunotherapy with PD-1 inhibitors or CTLA-4 inhibitors or combination of both between Nov 2010 and Oct 2017. Patients were divided into Abx(+) and Abx(-) groups that were defined as patients exposed or not exposed to antibiotics respectively. The time frame for antibiotic exposure was taken from 6 months prior to 1 month after initiation of immunotherapy. We compared progression free survival (PFS), overall survival (OS) and response rate (RR) between the two groups. RR was calculated based on the entire length of follow-up.  Results: Out of 108 patients, 66 were men, with a mean age 64.6 ± 15.1 years. 46 patients were exposed to antibiotics of varied classes. Median PFS in abx(+) group [88 days] was shorter as compared to abx(-) group [322 days].Patients in abx(-) group had a 68% reduced risk of progression within 200 days of immunotherapy initiation adjusting for sex, age and number of immunotherapy cycles . Median OS in ab(+) group [294 days] was shorter as compared to abx(-) group [573 days]. Response rate defined as percentage of patients whose cancer was stable or entered remission was 12.9% in abx(-) group as compared to 8.7% ab(+) group. Patients in abx(-) group had a 52% reduced risk of death adjusting for sex, age and number of immunotherapy cycles. Conclusions: Antibiotic exposure is associated with poorer outcomes in patients with advanced metastatic melanoma being treated with PD-1/CTLA-4 inhibitors which is likely related to alteration of gut microbiome. Antibiotics should be prescribed with caution in patients undergoing treatment with immune check point inhibitors. These data should be validated in a larger patient population.

In this retrospective study of 108 melanoma patients treated with immunotherapy, it was noted that 46 were given antibiotics at some point between 6 months prior and 1 month after starting their immunotherapy treatment.  PFS was 88 days in those who took antibiotics and 322 days in the group who didn't.  OS was 294 days in the antibiotic group - 573 days in the non-antibiotic group.  Response rate was 8.7% in the group that had taken antibiotics vs 12.9% in the group that had not been exposed to antibiotics.  As I wrote in the post I put up in April:  "So...if you really NEED antibiotics, they may save your life and will certainly decrease misery. BUT, if you DON'T really NEED them...they can cause harm, in lots of ways."

Now, there's this:

Cumulative Antibiotic Use Significantly Decreases Efficacy of Checkpoint Inhibitors in Patients with Advanced Cancer.  Tinsley, Zhou, Tan, et al.  Oncologist. 2019 Jul 10. 

With the advent of immunotherapy, substantial progress has been made in improving outcomes for patients with advanced cancer. However, not all patients benefit equally from treatment, and confounding immune-related issues may have an impact. Several studies suggest that antibiotic use (which alters the gut microbiome) may result in poorer outcomes for patients treated with immune checkpoint inhibitors (ICI).

This is a large, single-site retrospective review of n = 291 patients with advanced cancer treated with ICI (n = 179 melanoma, n = 64 non-small cell lung cancer, and n = 48 renal cell carcinoma). Antibiotic use (both single and multiple courses/prolonged use) during the periods 2 weeks before and 6 weeks after ICI treatment was investigated.

Within this cohort, 92 patients (32%) received antibiotics. Patients who did not require antibiotics had the longest median progression-free survival (PFS), of 6.3 months, and longest median overall survival (OS), of 21.7 months. With other clinically relevant factors controlled, patients who received a single course of antibiotics had a shorter median OS (median OS, 17.7 months), and patients who received multiple courses or prolonged antibiotic treatment had the worst outcomes overall (median OS, 6.3 months). Progression-free survival times were similarly affected.

This large, multivariate analysis demonstrated that antibiotic use is an independent negative predictor of PFS and OS in patients with advanced cancer treated with ICIs. This study highlighted worse treatment outcomes from patients with cumulative (multiple or prolonged courses) antibiotic use, which warrants further investigation and may subsequently inform clinical practice guidelines advocating careful use of antibiotics.

Antibiotic use is negatively associated with treatment outcomes of immune checkpoint inhibitors (ICI) in advanced cancer. Cumulative antibiotic use is associated with a marked negative survival outcome. Judicious antibiotic prescribing is warranted in patients receiving treatment with ICI for treatment of advanced malignancy.

Granted none of the patients in this study had melanoma.  And, as I noted above, if you need antibiotics, they can be essential and life saving.  But - if they are not required - they may cause us more harm than good.

And, finally - this:

Modifiable Host Factors in Melanoma: Emerging Evidence for Obesity, Diet, Exercise, and the Microbiome.  Warner and McQuade. Curr Oncol Rep. 2019 Jul 1.

We discuss how potentially modifiable factors including obesity, the microbiome, diet, and exercise may impact melanoma development, progression, and therapeutic response.  Obesity is unexpectedly associated with improved outcomes with immune and targeted therapy in melanoma, with early mechanistic data suggesting leptin as one mediator. The gut microbiome is both a biomarker of response to immunotherapy and a potential target. As diet is a major determinant of the gut microbiome, ongoing studies are examining the interaction between diet, the gut microbiome, and immunity. Data are emerging for a potential role of exercise in reducing hypoxia and enhancing anti-tumor immunity, though this has not yet been well-studied in the context of contemporary therapies. Recent data suggests energy balance may play a role in the outcomes of metastatic melanoma. Further studies are needed to demonstrate mechanism and causality as well as the feasibility of targeting these factors.

NO body shaming here!!!!!!!!!!!!  Eat your good cooties (kefir, kimchi, yogurt, saukraut, etc) and live LARGE!!!!!!!!!!!!!! 

For what it's worth! - c