ADDING A PROBIOTIC

In conversation with my oncologist I was made aware that there are clinical studies which show that a probiotic could enhance the performance of immune checkpoint inhibitors - which was of particular interest as I was now taking pembrolizumab (Keytruda) alone.
The probiotic used in the studies is Clostridium butyricum MIYAIRA 588 - a specific strain of anaerobic, butyric acid forming, Gram-positive bacterium isolated from a soil sample in Japan.
Its primary use as a supplement is to regulate gut health (see the label above from the product I ordered from a supplier that imports from Japan).
As documented earlier in my blog - 7 years ago, I began a low carb/high fat diet which, along with green exercise and intermittent and periodic prolonged fasting, was key to losing 100 lbs and reversing type 2 diabetes.  I have maintained my weight and blood glucose by continuing to follow this regimen.  CBM 588 is believed to modulate some potential gastroinstestinal side effects of a ketogenic diet, increase insulin sensitivity and optimize lipid metabolism.  While more work needs to be done, in addition to bowel regulation, CBM 588 appears to be a good addition to my diet.
What is most impressive for my current health journey are the results being reported when CBM 588 is used with immune checkpoint inibitors - specifically for renal and non-small cell lung cancer.  The gut biome is known to play a key role in regulating the immune system.  Imbalances, known as dysbiosis can lead to immune disfunction. 
In a phase 1b trial for renal cancer - the objective response rate (ORR) was 58% for those receiving immunotherapy and CBM 588, compared to 20% for those receiving immunotherapy alone.  The immunotherapy was a combination of nivolumab (Opdivo) and ipilimumab (Yervoy).  Nivolumab is a PD-1 checkpoint inhibitor like pembrolizumab (Keytruda).   Ipilimumab targets the CTLA-4 receptor on T-cells.  The improvements are consistent with the hypothesis that supplementation with CBM 588 works to reduce dysbiosis, support the immune system and improve efficacy of immune checkpoint inhibitors.  A phase 1b trial examines safety - e.g. dosage and pharmokinetics.  A phase 2 trial is planned to look at efficacy (as well as further examination of safety and optimal dosing).
In the lung cancer study cited - 75% of the patients had a combination of chemotherapy and pembrolizumab.  The addition of CBM 588 was associated with a longer overall survival and progression free survival.
Less relevant for me, but interesting nonetheless - CBM 588 also been shown to be as effective against (non-muscle invasive) bladder cancer cells and potentially safer than the first immunotherapy  BCG in in-vitro and in-vivo laboratory studies.
I found a supplier of Strong Miyarisan, a supplement supplying CBM 588 on eBay (see label above).  Each tablet contains 30 mg CBM 588.  The recommended adult dose is 3 tablets 3 times per day or 270 mg.  The dose administered in the renal cancer trial was 80 mg twice per day or 160 mg.
I would welcome (and will lobby as I can for) a clinical trial of patients beginning a first line treatment of Padcev + Keytruda for locally advanced or metastatic muscle invasive bladder cancer  - one arm supplemented with CBM 588 - the other without.  This is the pathway that would allow doctors to prescribe CBM 588 as part of treatment.
In the meantime, I am proceeding with the assumption that CBM 588 may boost efficacy of pembrolizumab. I am going to start with 2 tablets 3 times per day or 180 mg.​  As this supplement is considered safe, I believe that at a minimum I will have good intestinal health, likely benefits for my ketogenic diet (including insulin sensitivity and improved bowel health) and potentially improved efficacy of Keytruda fighting any cancer that remains.  I will report any adverse effects.  I currently have no evidence of disease by imaging or circulating tumor DNA and I am just one patient so it will be difficult to know if the addition of CBM 588 has been effective (or harmful) - I will continue to monitor any relevant trials. 
As with any decision affecting treatment - patients should discuss with their care team.