Could We Soon See A Vaccine For Heroin?

vaccine heroinThe death of Prince has been a turning point of how serious the opioid addiction epidemic has become. Almost every medical pain specialist has been aware of the problems with opioids, pain and addiction, but now others are taking note. There are many concerns with prescribing opioids, from whether they actually help control pain, are there better treatments, and how many additional problems they are causing. We know one of the big problems caused by opioids that has become horribly worse is opioid addiction. Many people with and without pain are addicted to opioids. A new way to help treat addiction is in development – vaccines.

The information for this blog comes mainly from an article by Susan Giados published in the July 9,2016 issue of Science News Magazine. For those who are interested in a variety of scientific topics, this is a twice a month magazine, usually about 30 pages long packed with short fascinating articles. Well worth looking into.

The Heroin Scene

Heroin and opioid medications are accounting for about 30,000 overdose deaths a year. Here’s how it came to be popular in the US.

1960’s – Heroin first came on the drug scene in big numbers in the early 1960’s. It was a strong drug that produced an intense high. Most users came to the drug while searching for more intense highs, but the drug was not particularly pure or cheap.

1970’s – Major education and opium eradication efforts into the 1970’s suppressed its use.

1980’s and 1990’s – The late 1980’s introduced long acting opioids like OxyContin onto the market, and big pharma pushed these drugs as safe and as the answer to any all pain was simply to take a pill.

2000’s – By the early 2000’s opioids were the first and most common way to treat pain, and every doctor was prescribing them. The rate of addiction rose drastically, and as the awareness has grown, the access to prescriptions has slowly become harder. Opioid addicts now were everywhere.

Now comes into play some very interesting economics. Addiction itself has driven a market to supply people with opioid medication. It spawned an under culture of “pill mills” where almost anyone could go and get a supply of opioid pills. Many people would “doctor shop” for pills, use some and sell the rest for money. Drug cartels started to get into the mix manufacturing and selling them, further fueling addicts. The government then started clamping down on the supply since about 2010. The drug cartels have long had the ability to make heroin, and now they knew they could make large, pure amounts cheaply. For addicts, those who got hooked on pain pills for any number of reasons now saw heroin as a cheaper and often easier to obtain option than prescription medications. Now heroin has become a major problem as more addicts are turning to that to treat their cravings and pain.

Addiction to opioids has become a huge problem. There now are three medications that are used in the treatment of addiction; methadone, buprenorphine, and naltrexone.  Methadone and buprenorphine are used to reduce cravings, and must be continued indefinitely.  Naltrexone is used to block receptors and is used almost exclusively to reverse opioid overdoses. Unfortunately of those who seek treatment for addiction, only 25% end up receiving medications to help prevent relapsing back into addiction. Vaccines were first attempted in the 1970’s, but the science and cost of development were barriers, and the methadone was cheap and easy to use.

Addition and Vaccines

Now a little additional primer on addiction. Opioid drugs alter the brain pleasure circuitry and cause changes in the structure and function of the brain. Opioids act on the nucleus accumbens in the brain, and they increase the amount of dopamine in the brain. Opioids also act on the mu receptors throughout the nervous system, stimulating dopamine. These are the same chemicals that stimulate the pleasure centers in the brain and reinforce enjoyable activities like eating, sex or listening to good music. Dopamine, in other words, is what is stimulated by compounds like opioids and by stimulating pleasure. Over time, drugs of abuse can change the circuitry in the brain, decreasing the sensitivity of the reward centers and disrupt the centers involved in self control. Addicts tend to lose the ability to enjoy the normal every day activities, and then they need higher and higher doses of drugs to stimulate euphoric/happy feelings. The need to feel pleasure drives the brain, impairs decision making and self-control, and then the only drive is to take drugs just to stay on an even level.

The goal of a vaccine is to train the body’s own immune system to identify the specific offending drug molecules and rid the body of them at even high doses. One of the vaccines being developed is aimed at heroin and its breakdown product morphine. To be effective, heroin in the body breaks down quickly to morphine, and both these compounds need to be targeted to be helpful. The other problem is when going after a drug, there are millions of molecules in the body suddenly, unlike an infection with a few replicating viruses. So to develop a robust vaccine to stimulate the body’s immune systems and chemicals to rid it of certain compounds like opioids is a bit difficult.  

So far scientists have been successful in developing a vaccine specific for heroin and the breakdown to morphine that works in rats. The vaccine trains the immune system to neutralize the compounds and even fatal doses of drugs can be handled. The intake of heroin or morphine no longer produces a high, and drug seeking is not pleasurable. A series of three shots was able to produce months of ability to block drug seeking and pleasure by specific opioids. A second vaccine similar to the one for heroin is being developed for fentanyl. After a number of months, the brain starts to reset to more normal patterns of stimuli producing pleasure versus the strong pull to using narcotics. Blocking the drug seeking and pleasure of opioids does also affect all the pain relieving abilities, and the vaccines essentially cause the body to destroy these compounds making them ineffective for any purpose.

Using vaccines is another tool to control addictive behavior in the future once they are perfected for human use. They will be only for specific compounds, like heroin, morphine and fentanyl and not every single narcotic in general. They will be targeted at the most abused compounds and in that way allow a person still to be able to use certain other opioids if necessary for pain control.

Addiction does occur in the pain patient population. The percent of addicted patients in studies is highly variable, on the low side it may be 2-5 percent, although a common number is up to 17% or higher. Addiction is occurring when the need to take a drug is overriding, judgement is impaired and normal activities are suppressed over the needs for getting and taking the medication. Further, the amount of drug needed is escalating fairly rapidly. When addiction becomes an issue, then being weaned from the whole category of drug is needed and appropriate psychological help for addiction and full treatment is necessary.