Treatment with methylnaltrexone, a peripherally acting μ opioid receptor antagonist approved for the treatment of opioid-induced constipation, was associated with improved overall survival in patients with advanced cancer, a post-hoc analysis published in Annals of Oncology has shown.1
Because preclinical data has suggested that μ opioid receptor activation may play a role in cancer progression, researchers sought to conduct an unplanned post-hoc analysis of the effect of methylnaltrexone on survival in 229 patients with advanced end-stage cancer with opioid-induced cancer.
The data were from 2 randomized trials, one phase 3 and one phase 4, which compared subcutaneous methylnaltrexone with placebo for opiod-induced constipation.
Results showed that treatment with methylnaltrexone was associated with a median overall survival of 76 days (95% CI, 43-109) vs 56 days (95% CI, 43-69) with placebo (P =.033).
Patients who achieved a response to methylnaltrexone has a median overall survival of 118 days (95% CI, 59-177) compared with 55 days (95% CI, 40-70) among those who did not respond to treatment (P <.001).
After adjusting for multiple variables, the researchers found that response to therapy (P =.002) and albumin level of 3.5 or higher (P <.001) independently predicted for improved overall survival.
Of note, there was no difference in overall survival between those treated with methylnaltrexone and those given placebo among the 134 patients with advanced illness who did not have cancer (P =.88).
The findings suggest that further prospective investigation of methylnaltrexone in cancer therapy is warranted.
1. Janku F, Johnson LK, Karp DD, Atkins JT, Singleton PA, Moss J. Treatment with methylnaltrexone is associated with increased survival in patients with advanced cancer. Ann Oncol. 2016 Aug 29. doi: 10.1093/annonc/mdw317. [Epub ahead of print]