Quit Smoking with an Improved Nicotine Vaccine
Scientists at the Scripps Research Institute (SRI) in California are on the verge of releasing a new and improved nicotine vaccine to help smokers quit the habit by inhibiting nicotine molecules from reaching the brain, effectively preventing the user from deriving pleasure through smoking. The vaccine’s intention is to utilize the smoker’s immune system to create antibodies that “attack” or attach to nicotine molecules so they don’t cross the blood-brain barrier, blocking off the body’s physiological reward system.
In 2009, a nicotine vaccine called NicVAX by Nabi Biopharmaceuticals was undergoing phase III clinical trials and another was held in 2010. In 2011, the company announced the vaccine as a failure stating it was no better than a placebo. Its failure stemmed from the vaccine’s attempt to target both mirror images, or enantiomers (optical isomers), of nicotine which is a chiral molecule that has a non-superimposable twin, or its mirror image. One enantiomer, L-nicotine, is found in 99 percent of tobacco, so the vaccine was only successful in 30 percent of test subjects in the clinical trials.
SRI researchers are developing a nicotine vaccine that targets only L-nicotine so that the immune system does not waste time and resources developing unnecessary antibodies. When tested in rats, the L-nicotine vaccine produced more than 60 percent antibodies against L-nicotine compared to its haptens counterpart—a vaccine that targeted a 50-50 racemic mixture of L-nicotine and R-nicotine.
The scientists are currently working on how to institute consistency of the nicotine vaccine in individuals’ immune systems in light of variations that exist across large populations. The vaccine may help with the cravings but does not contend with nicotine withdrawal symptoms, which may be a factor in the effectiveness of the nicotine vaccine success rate in aiding smokers to quit.
Immunotherapy Melanoma Drug Keytruda Approved by FDA to Fight Metastatic Skin Cancer
The U.S. Food and Drug Administration (FDA) recently approved Keytruda (pembrolizumab)—manufactured by Merck—an immunotherapy melanoma drug, to be used against metastatic skin cancer. The FDA allotted Keytruda “breakthrough” status because it worked extremely well during phase I clinical trials, and the drug was approved three-and-a-half years after its first administration.
The purpose of immunotherapy is to boost the body’s immune defenses to attack cancer cells. Keytruda is essentially an antibody that targets a protein that acts as an immune inhibitor called programmed death receptor, or PD-1. The cancer cells commandeer PD-1 receptors, which allow them to cloak themselves from T-cells, the immune system’s main defense mechanism in fighting “non-self” artifacts within the body.
Keytruda is not the first FDA-approved immunotherapy melanoma drug on the market. Zelboraf (vemurafenib) and Yervoy (ipilimumab) are also approved immunotherapies to fight advanced melanoma, along with three others. The new drug is scheduled for use in those with advance stage melanoma after Yervoy fails. In the clinical trial, Keytruda has shown to shrink tumors in 72 percent of the subjects, in which 34 percent of the patients had their tumor size shrink by more than 30 percent and did not regrow.
Bristol-Meyers Squibb’s immunotherapy melanoma drug Opdivo (nivolumab), that also blocks PD-1 receptors, is slated for FDA approval in 2015. Opdivo, once approved, is scheduled for use for in metastatic melanoma patients before Yervoy or in conjunction with Yervoy to shrink tumors for an extended period of time.
According to the American Cancer Society, melanoma is the most dangerous form of skin cancer. When caught in its early stages, it is highly curable, but not so much in the later stages. Melanoma has a tendency to rapidly to spread to other parts of the body, hence decreasing survivability rate in advanced stages. Even though melanoma accounts for less than 2 percent of skin cancers, it is responsible for majority of skin cancer deaths.