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Ann Oncol. 2016 Nov;27(11):2032-2038. Epub 2016 Aug 29.

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

Author information

1
Department of Investigational Cancer Therapeutics (Phase I Clinical Trials Program), The University of Texas MD Anderson Cancer Center, Houston.
2
Salix Pharmaceuticals Inc., Raleigh.
3
Department of Medicine, Section of Pulmonary and Critical Care.
4
Department of Anesthesia and Critical Care, Pritzker School of Medicine, The University of Chicago, Chicago, USA.
5
Department of Anesthesia and Critical Care, Pritzker School of Medicine, The University of Chicago, Chicago, USA jm47@midway.uchicago.edu.

Abstract

BACKGROUND:

Methylnaltrexone (MNTX), a peripherally acting μ-opioid receptor (MOR) antagonist, is FDA-approved for treatment of opioid-induced constipation (OIC). Preclinical data suggest that MOR activation can play a role in cancer progression and can be a target for anticancer therapy.

PATIENTS AND METHODS:

Pooled data from advanced end-stage cancer patients with OIC, despite laxatives, treated in two randomized (phase III and IV), placebo-controlled trials with MNTX were analyzed for overall survival (OS) in an unplanned post hoc analysis. MNTX or placebo was given subcutaneously during the double-blinded phase, which was followed by the open-label phase, allowing MNTX treatment irrespective of initial randomization.

RESULTS:

In two randomized, controlled trials, 229 cancer patients were randomized to MNTX (117, 51%) or placebo (112, 49%). Distribution of patients' characteristics and major tumor types did not significantly differ between arms. Treatment with MNTX compared with placebo [76 days, 95% confidence interval (CI) 43-109 versus 56 days, 95% CI 43-69; P = 0.033] and response (laxation) to treatment compared with no response (118 days, 95% CI 59-177 versus 55 days, 95% CI 40-70; P < 0.001) had a longer median OS, despite 56 (50%) of 112 patients ultimately crossing over from placebo to MNTX. Multivariable analysis demonstrated that response to therapy [hazard ratio (HR) 0.47, 95% CI 0.29-0.76; P = 0.002) and albumin ≥3.5 (HR 0.46, 95% CI 0.30-0.69; P < 0.001) were independent prognostic factors for increased OS. Of interest, there was no difference in OS between MNTX and placebo in 134 patients with advanced illness other than cancer treated in these randomized studies (P = 0.88).

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.

CLINICAL TRIALS NUMBER:

NCT00401362, NCT00672477.

KEYWORDS:

cancer; constipation; methylnaltrexone; mu opioid receptor; opioids; survival

PMID:
27573565
DOI:
10.1093/annonc/mdw317
[Indexed for MEDLINE]

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