repurpose drugs that work for other diseases<\/a>. Already approved drugs with broad antiviral activity could, in theory, be rapidly deployed if proven effective against measles.\u00a0\u00a0<\/p>\nBut some researchers hope to find a new drug that could treat measles and its viral cousins.\u00a0<\/p>\n
Richard Plemper, a virologist and antiviral drug developer at Georgia State University in Atlanta, began using the measles virus as a tool to study how the immune system works in the early 2000s, around the time the United States achieved measles elimination. When measles remained a global problem, he says, \u201cit actually became worthwhile to consider, do we maybe need a measles drug?\u201d<\/p>\n
Studies suggested that a chemical probe that the team designed to switch off certain viral functions, including replication,\u00a0might be turned into an effective treatment. But because of the availability and potency of the measles vaccine, Plemper decided to search for a drug for the entire subfamily of viruses that measles belongs to. The Orthoparamyxovirus subfamily includes\u00a0Nipah virus\u00a0and two human parainfluenza viruses, which also lack treatments.\u00a0<\/p>\n
Like many viral infections, including influenza, these viruses\u00a0replicate and cause disease quickly. Once a person becomes sick, typically several days after exposure, the window of opportunity for treatment is short. \u201cThe paradigm must be the earlier we treat, the better,\u201d Plemper says. The virus may have already stopped replicating by the time a person is severely ill, making antiviral treatment ineffective.\u00a0<\/p>\n
Plemper and colleagues tested\u00a0more than 100,000 potential compounds, one of which they developed into the antiviral candidate GHP-88310. The drug has showed promise in ferrets infected with canine distemper virus, an Orthoparamyxovirus that is sometimes used as a proxy for measles in small mammals. Though rodents and ferrets can get infected with the measles virus, they don\u2019t have all the same symptoms that people do.<\/p>\n
GHP-88310\u00a0dampened viral replication in the ferrets\u00a0when given daily starting three days after infection, Plemper and colleagues reported May 22 in\u00a0Science Advances<\/em>. All treated animals also survived. By binding to a key viral protein, the drug \u201cputs a foot on the brake,\u201d Plemper says.<\/p>\nAnd the target protein is important for replication across this subfamily of viruses. \u201cThis compound is so attractive because it is equally effective against many of the related major human pathogens, of which measles is one,\u201d Plemper says.<\/p>\n
The drug still has a long way to go before it could be used in people, but he hopes that it could one day help people who aren\u2019t vaccinated, perhaps even as a prophylactic to prevent measles after an exposure.\u00a0<\/p>\n
A helping hand for the immune system<\/h2>\n Measles-attacking monoclonal antibodies produced in the lab might be another treatment option.\u00a0<\/p>\n
\u201cYou can think of monoclonal antibodies as kind of an on-demand immunity,\u201d Hastie says. Vaccines work by teaching the body how to recognize measles and developing long-term defenses over a few weeks. Monoclonal antibodies\u00a0\u2014\u00a0which are widely approved to treat\u00a0viral infections like RSV\u00a0and\u00a0Ebola, as well as some cancers and autoimmune diseases\u00a0\u2014 deliver immune-triggering proteins that get to work immediately. \u201cWhat we can do with monoclonal antibodies is essentially deliver hand-picked antibodies that are the best of the best to try and control the viral infection at the time of infection, either preexposure or post-exposure,\u201d she says.\u00a0<\/p>\n\n\n\u201cVaccines, to some degree, fell victim to their own success.\u201d<\/p>\n
Richard Plemper<\/strong>Hastie and colleagues recently determined the structures of four measles antibodies from a vaccinated person. Infusing those antibodies into infected cotton rats\u00a0decreased the amount of measles virus\u00a0in the rats\u2019 lungs, the team reported May 7 in\u00a0Cell Host and Microbe<\/em>. One antibody even reduced the virus to an undetectable level. Because measles is spread through respiratory droplets, the findings hint that treatment might dampen transmission.\u00a0<\/p>\nThe work follows studies of a different monoclonal antibody candidate called mAb 77, which also\u00a0diminished the viral load in cotton rats. But that antibody\u00a0\u2014\u00a0which is\u00a0undergoing additional testing in primates\u00a0\u2014\u00a0originated from a mouse. Using it in people requires tweaking the immune protein so that the body doesn\u2019t treat it as a foreign invader. The four human antibodies wouldn\u2019t require that step. They next need to be tested in nonhuman primates.<\/p>\n
One drawback with monoclonal antibodies is that treatment can be more expensive than an antiviral, Hastie says. Because the antibodies are highly specific for their targets, however, the chance of side effects is low.\u00a0<\/p>\n
The challenge of clinical trials<\/h2>\n There are no clinical trials currently under way for measles treatments, and getting one started could be difficult. One issue is that there need to be enough cases for a meaningful sample size, and in terms of trial logistics, those cases need to be in a predictable timeframe and geographic area.<\/p>\n
With measles, \u201cwe don\u2019t know exactly where the outbreaks will happen,\u201d Plemper says. Thousands of people get sick with measles every year in some countries\u00a0\u2014\u00a0Yemen, Pakistan, Sudan and others\u00a0\u2014\u00a0but that\u2019s often because people there don\u2019t have easy access to vaccines. \u201cIf you cannot reach the people for vaccination, then you would struggle to enroll them for a clinical trial,\u201d Plemper says.\u00a0<\/p>\n
There is also the question of who would fund such a trial, since few people might require treatment, though some U.S. biotech companies are\u00a0taking steps to begin testing monoclonal antibodies. Another is how it could be done ethically. Any unvaccinated children should be offered the vaccine rather than enrolled in a treatment trial.\u00a0\u00a0<\/p>\n
Because of these challenges, Plemper and his team are planning to test GHP-88320 on a different, but closely related, virus first: human parainfluenza virus type 3. The common virus, which infects people globally, is an \u201cirritation\u201d most of the time, Plemper says, causing mild, coldlike symptoms. But infections can be life-threatening for transplant patients whose immune systems are suppressed to lower the risk of organ rejection.<\/p>\n
The hope is that GHP-88310 will prove helpful against that virus, which doesn\u2019t have a vaccine. And because measles is in the same family of viruses, it could ultimately be available for use during measles outbreaks, too.<\/p>\n
\u201cVaccines, to some degree, fell victim to their own success,\u201d Plemper says. Preventing disease in the first place will always be the best approach, but emerging antivirals and monoclonal antibodies could provide a needed backup, he notes. \u201cMaybe we need this last kick to completely silence the virus.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
A highly effective vaccine has long kept measles at bay in many parts of the world. But as childhood vaccination rates drop, leaving a growing population vulnerable to the extremely contagious virus, one question takes on new urgency: What\u2019s the backup plan? There are currently no antiviral treatments against measles. Though physicians can offer ways […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[10],"tags":[],"_links":{"self":[{"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=\/wp\/v2\/posts\/105071"}],"collection":[{"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=105071"}],"version-history":[{"count":0,"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=\/wp\/v2\/posts\/105071\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=105071"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=105071"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.adviews.info\/news\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=105071"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}