Zohydro (Hydrocodone Bitartrate) for the Treatment of Chronic Pain, United States of America
Zohydro (hydrocodone) is a single-entity oral drug indicated for the treatment of chronic pain. Zogenix, a San Diego-based pharmaceutical company, is developing and commercialising the drug in the US.
In May 2012, Zogenix submitted a New Drug Application (NDA) to the US Food and Drug Administration (FDA) for Zohydro. The drug is expected to hit the US market in early 2013.
Chronic pain is a condition that affects any part of the body and lasts for long periods of time. It is persistant and the pain signals keep firing in the nervous system for weeks, months and years. It can suppress the immune system and decrease the body's production of natural painkillers, and can also increase anxiety, stress, depression and anger.
It is estimated that about 116 million people in the US are affected by chronic pain and its economic costs throughout the nation are about $560bn to $635bn annually.
One of the treatments for chronic pain is through the use of opioid pain reliever hydrocodone. The drugs that are currently available in the market are combination products of hydrocodone with mostly acetaminophen or ibuprofen.
Zohydro - single-entity hydrocodone therapy
Zohydro is a single-entity hydrocodone therapy, which contains a semi-synthetic opioid. The detailed mechanism of action of the drug is not known. It is believed to control moderate to severe pain when administered every 12 hours. It does not contain any acetaminophen which causes liver toxicity. The extended-release capsules are available in 10mg, 20mg, 30mg, 40mg and 50mg doses.
Zohydro has been developed using Spheroidal Oral Drug Absorption System (SODAS), a drug delivery technology patented by Alkermes Pharma Ireland. In 2012, Zogenix signed a licence agreement with Alkermes to pay $1m for using the patented technology.
Zogenix submitted the NDA to FDA for Zohydro based on two phase III clinical trials known as 801 and 802 studies. The studies enrolled more than 1,100 patients with chronic pain.
As conditions such as diabetes become more common, the market for new pain drugs is becoming increasingly competitive.
Zogenix conducted the 801 efficacy study on Zohydro between March 2010 and October 2011. It was an efficacy study which met its primary efficacy endpoint by demonstrating that Zohydro significantly improved chronic pain relief when compared to placebo. The study also met two secondary endpoints of improvement of overall satisfaction of medication and the proportion of patients with at least 30% improvement in pain intensity.
The most commonly reported side effects of Zohydro were nausea, constipation, somnolence, headache, fatigue, dizziness, vomiting, dry mouth and pruritus.
Zogenix conducted the 802 safety study on Zohydro between May 2010 and January 2012. It was an open label study. The patients were administered with Zohydro for 12 months. The study results showed that the drug was safe and well tolerated, and the incidence of adverse events was consistent with study 801.
The primary endpoint of the study was evaluation of long-term safety and tolerability of Zohydro.
If approved by the FDA, Zohydro will be the first hydrocodone product to offer the benefit of less frequent dosing. It is also likely to be the first hydrocodone drug without acetaminophen combination.
The hydrocodone drugs currently available in the market are combination drugs that may result in liver toxicity on prolonged use.
Egalet, a Denmark-based pharmaceutical company, is also developing a pure hydrocodone product for chronic pain treatment. The drug is currently in phase I clinical trials and may hit the market by 2015.
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