Treatment with methylnaltrexone is associated with increased survival in patients with advanced cancer

[Olga]

Methylnaltrexone is a laxative used to deal with the opioid-induced constipation (OIC). Most advanced cancer patient have to take some opioids as a pain killers when disease advances, their side effect is severe constipation. Many drugs were tried to deal with it, then they suspected that a constipation is caused by the MOR receptor so they invented a Methylnaltrexone. It is a peripherally acting μ-opioid receptor (MOR) antagonist. Coincidentally there is a preclinical data suggest that MOR activation can play a role in cancer progression and can be a target for anticancer therapy, so the study looked at the survival effect (and for the laxative effect too - the main purpose of this drug).

Treatment with methylnaltrexone is associated with increased survival in patients with advanced cancer.
https://www.ncbi.nlm.nih.gov/pubmed/27573565


CONCLUSION: This unplanned post hoc analysis of two randomized trials demonstrates that treatment with MNTX and, even more so, response to MNTX are associated with increased OS, which supports the preclinical hypothesis that MOR can play a role in cancer progression. Targeting MOR with MNTX warrants further investigation in cancer therapy.
So this drug looks like a good tool in both ways. (it is sold under the brand name Relistor).