"Alkemes (NASDAQ: ALKS) recentlyy announced positive Phase 3 results testing naltrexone for extended-release injectable suspension for the treatment of opioid dependence," says biotech specialist John McCamant.
In The Medical technology Stock Letter, he explains, "In addition to the use of heroin, opioid abuse and addiction includes prescription pain relievers, and represents a growing public health problem in the U.S. and a significant opportunity for the company."
McCamant continues, "The six-month, 250-patient, Phase 3 study met its primary efficacy endpoint and data showed that patients treated once-monthly with naltrexone (XR-NTX) demonstrated statistically significant higher rates of clean (opioid-free) urine screens, compared to patients treated with placebo.
"Based on the positive results of this Phase 3 study, the company plans to file a supplemental New Drug Application (sNDA) with the FDA in the first half of calendar 2010.
"XR-NTX, marketed by ALKS as Vivitrol, is an opioid antagonist administered once-monthly by intramuscular injection and is approved in the U.S. for the treatment of alcohol dependence.
"If approved by the FDA for the treatment of opioid dependence, XR-NTX has the potential to be the first and only non-narcotic, non-addictive drug agent available in a once-monthly formulation.
'Because the drug is already approved, it only needs to complete one Phase 3 trial as opposed to two trials for new drug candidates to be eligible for FDA approval.
"This is a significant positive as the opioid dependence market is projected to be over $1 billion in 2009, and represents a second life for Vivitrol which has been a major disappointment in the alcohol dependence market.
"The main competitors to Vivitrol in the opioid dependence market will be Subutex and Suboxone; because these drugs are partial agonists, the DEA has designated the drugs as Schedule III to acknowledge the potential abuse risk.
"We believe that Vivitrol will be able to compete effectively against Suboxone and any potential generic versions of Suboxone, as it has much less potential for drug abuse. The company estimates that there are about 2,000 doctors who write 80% of the prescriptions for opioid dependence.
"We estimate Vivitrol sales into the opioid dependence market will reach $250 million a few years after launch, with peak sales potential of $500 million.
"The company has had ongoing discussions with the FDA and believes it will be able to file the sNDA in the first half of 210 with possible approval in the first half of 2011.
"In related news, ALKS announced the initiation of a Phase 2 clinical study of ALKS 33, an investigational oral opioid modulator for the potential treatment of alcohol dependence and other central nervous system disorders.
"The efficacy of ALKS 33 will be evaluated based on the percentage of patients who are abstinent from heavy drinking during the eight-week evaluation phase.
"ALKS 33 is an oral opioid modulator that builds on Alkermes' unique understanding of biological pathways and opioid pharmacology as well as the company's clinical and commercial knowledge in the field of addiction."
by Steven Halpern
December 3, 2009