Methylnaltrexone for Treatment of Opioid-Induced Constipation in Advanced Illness Patients

Neal Slatkin, MD, Jay Thomas, MD, PhD, Arthur G. Lipman, PharmD, George Wilson, MD, Michelle L. Boatwright, MD, Charles Wellman, MD, Donna S. Zhukovsky, MD, Richard Stephenson, MD, Russell Portenoy, MD, Nancy Stambler, MS, and Robert Israel, MD

Department of Supportive Care, Pain and Palliative Medicine, City of Hope Medical Center, Duarte, California; San Diego Hospice & Palliative Care, San Diego, California; University of Utah Health Sciences Center, Salt Lake City, Utah; University of Florida College of Medicine, Jacksonville, Florida; LifePath Hospice & Palliative Care, Inc., Tampa, Florida; Hospice of the Western Reserve, Cleveland, Ohio; The University of Texas M. D. Anderson Cancer Center, Houston, Texas; Hospice & Palliative Care Center, Winston-Salem, North Carolina; Beth Israel Medical Center, New York, NY; Progenics Pharmaceuticals, Inc., Tarrytown, New York

Methylnaltrexone, a peripheral mu-opioid receptor antagonist with restricted ability to cross the blood-brain barrier, may relieve opioid-induced constipation (OIC) without reversing analgesia. A total of 154 patients with advanced illness and OIC enrolled in a double-blind, randomized, placebo-controlled trial, with optional open-label phases (up to 4 months) in hospice and palliative care centers during 2003–2005. They received a single subcutaneous injection of methylnaltrexone (0.15 mg/kg or 0.3 mg/kg) or placebo. Laxation response within 4 hours was 62% and 58% for methylnaltrexone 0.15 mg/kg and 0.3 mg/kg, respectively, compared with 14% for placebo (P < 0.0001; each dose vs placebo). Approximately half of the methylnaltrexone responders defecated within 30 minutes of dosing. Open-label phase response rates mirrored those for methylnaltrexone during the double-blind phase. There was no change in pain scores or evidence of central opioid withdrawal. The most common adverse events (AEs) were abdominal pain and flatulence. Three patients had serious AEs attributed to methylnaltrexone. Subcutaneous methylnaltrexone was efficacious in rapidly inducing laxation and was generally well tolerated in patients with advanced illness and OIC. Trial Registration ClinicalTrials.gov Identifier: NCT00401362

J Support Oncol 2009;7:39–46   print e-mail full text 241 kb