Breakthroughs Blog: Malaria

The dapivirine ring (Photo: International Partnership for Microbicides) GHTC member the International Partnership for Microbicides (IPM) announced last week the results of two phase 3 clinical trials demonstrating that a monthly vaginal ring filled with the antiretroviral drug dapivirine can reduce the risk of HIV infection in women. The dapivirine ring is the first long-acting HIV prevention method designed for women, and IPM plans to seek regulatory approval for the product. The trials, conducted by IPM and the Microbicide Trials Network (MTN), enrolled 1,959 and 2,629 HIV-negative women and reduced infection rates by 31 and 27 percent, respectively. Efficacy rates were affected by participant age and adherence: for women over 21—who reportedly used the ring more consistently—the dapivirine ring reduced HIV infections by 37 and 56 percent in the trials led by IPM and MTN, respectively. As IPM Founding Chief Executive Officer Dr. Zeda Rosenberg stated, “These findings give new hope to many women at high risk who need more and different options to effectively protect themselves from HIV.” Researchers at the Scripps Research Institute (TSRI) and the US Army Medical Research Institute of Infectious Diseases have discovered potent antibodies against Ebola that could play a critical role in the research and development (R&D) of Ebola vaccines and treatment. The team identified 300 different antibodies against Ebola in the blood of a survivor, using molecules developed by TSRI to hunt for antibodies. Seventy-seven percent of the antibodies were able to combat the virus in mice, providing protection rates ranging from 60 to 100 percent. The three strongest antibodies all targeted distinct vulnerable spots on a certain protein found on the virus’ surface. Anti-Ebola antibodies have been used before, including in ZMapp™, an experimental treatment deployed during the 2014 Ebola outbreak. However, the number of known, effective antibodies was previously limited. This research also revealed a weak spot on the base of the aforementioned Ebola surface protein. As the virus mutates, so do the surface proteins. However, the base of these proteins remains largely the same, and thus, a weak spot on the base of the protein could be a potential target for manifold strains of the virus. US President Barack Obama is calling on Congress to allocate an additional US$200 million for the President’s Malaria Initiative (PMI), a 30 percent increase that would bring the Initiative’s budget to US$874 million. The funding would enable PMI to expand into three new countries—Sierra Leone, Cote D’Ivoire, and Cameroon; eliminate malaria in Zambia and Cambodia; scale up the use of bed nets; and advance R&D for vaccines, drugs, diagnostics, and vector control methods. As resistance grows to both malaria treatments and insecticides, the need for R&D remains critical. Further, resistance to the leading antimalarial was first reported in Cambodia and the most virulent strains are found on the border between Cambodia and Thailand. Thus, eliminating malaria in Cambodia would impede the global spread of drug resistance. With this new funding, PMI would be able to reach an additional 70 million people, ultimately reaching 92 percent of those in malaria endemic regions.

Photo: National Institute of Allergy and Infectious Diseases (NIAID) Gavi, the Vaccine Alliance, signed an advanced purchase commitment, pledging to spend US$5 million on an Ebola vaccine currently under development by pharmaceutical company Merck & Co. The vaccine candidate was tested on 4,000 people in Guinea last year, and the results were promising: despite all participants having close contact with at least one Ebola patient, none developed the disease more than ten days after vaccination (several days are required for a vaccine to confer protection). The vaccine candidate—VSV-EBOV—was developed and tested in partnership with the Canadian and US governments, however, without the urgency of an outbreak, public-sector support moving forward is limited. The agreement guarantees that there will be a market for the vaccine, assuring Merck & Co. that they can recover investments in advanced development and manufacturing. This move will also enable Gavi to establish a stockpile of the vaccine so that it can be rapidly deployed in future outbreaks. New research suggests that 2.6 million stillbirths occur each year, 420,000 of which are attributable to malaria or syphilis infections. These results underscore the need for testing and treatment of malaria and syphilis in pregnant women, particularly in endemic regions. Fortunately, there are low-cost interventions that could drastically reduce adverse pregnancy outcomes attributable to malaria and syphilis infections. The malaria parasite is able to reside in the placenta, even when undetectable in the mother’s blood, and thus, preventative treatment for malaria is critical. The antimalarial sulphadoxine-pyrimethamine, which costs a mere $0.20 per patient, is recommended for use in pregnant women in endemic areas. In east and southern Africa, an estimated 5 percent of pregnant women are infected with syphilis and in Tanzania, up to half of stillbirths are caused by syphilis. However, one dose of penicillin can cure both maternal and congenital syphilis and prevent stillbirth—at just $1.40 per person. While malaria- and syphilis-related stillbirths can be prevented with the scale-up of existing medicines, many more could be prevented with interventions that are not appropriate for low-resource settings, which is particularly concerning as 98 percent of stillbirths occur in low- and middle-income countries. Further, the cause of stillbirth is often unknown, according to the Global Alliance to Prevent Prematurity and Stillbirth, and additional research is needed to determine and address these causes. There is little incentive for pharmaceutical companies to invest in antimicrobial research and development (R&D): antibiotics are prescribed for short periods of time and competition among antibiotics keeps prices low. However, with the spread of drug resistance, the “[financial] value assigned to antibiotics and diagnostics often does not reflect the benefits they bring to society,” according to a declaration authored by 80 pharmaceutical and diagnostic companies and released at this year‘s World Economic Forum in Davos, Switzerland. The declaration calls on governments to work with the pharmaceutical industry to spur antimicrobial R&D, identifying innovative financing mechanisms, including prizes (a Market Entry Rewards initiative) and intellectual property–related incentives. In response, the companies pledge to invest in R&D for new antibiotics, as well as improved diagnostics to prevent the unnecessary use of antibiotics (i.e., for viral conditions).

President Obama 2016 State of the Union address. Photo: White HouseGHTC has long championed US leadership in global health and innovation, and we were encouraged to see President Barack Obama highlight these themes in his State of the Union address.On combating the 2014 Ebola epidemic in West Africa, the president highlighted a coordinated domestic and international effort to leverage expertise, resources, and value-add of all partners—a strategy we support for advancing global health R&D. He stated: Fortunately, there’s a smarter approach, a patient and disciplined strategy that uses every element of our national power. It says America will always act, alone if necessary, to protect our people and our allies; but on issues of global concern, we will mobilize the world to work with us, and make sure other countries pull their own weight… That’s how we stopped the spread of Ebola in West Africa. Our military, our doctors, and our development workers set up the platform that allowed other countries to join us in stamping out that epidemic. The president also discussed US investments in global health and development as a core piece of American foreign policy and national security, nodding to the Global Health Security Agenda, which coordinates domestic and international efforts to prevent, detect, and respond to global disease epidemics. In addition, his message called for renewed commitment and funding for US efforts to end the epidemics of HIV and AIDS and malaria: Leadership means a wise application of military power, and rallying the world behind causes that are right. It means seeing our foreign assistance as part of our national security, not charity. When we help African countries feed their people and care for the sick, that prevents the next pandemic from reaching our shores. Right now, we are on track to end the scourge of HIV and AIDS, and we have the capacity to accomplish the same thing with malaria — something I’ll be pushing this Congress to fund this year. President Obama also highlighted the transformative power of medical research to end endemic and emerging health threats: For the loved ones we’ve all lost, for the family we can still save, let’s make America the country that cures cancer once and for all. Medical research is critical. GHTC is pleased to see President Obama echo themes we have long advocated: partnerships and innovation are key to advancing health at home, and around the world.To curb the spread of emerging disease epidemics, we will need domestic and international commitment to work together and develop new tools and technologies to monitor, track, diagnose, and treat infectious disease. To finally end the scourge of malaria and achieve an AIDS-free generation, we will need renewed commitment to develop innovative vaccines and treatments that move us beyond current interventions. To cure noncommunicable diseases and other health challenges that plague developed and lower-income countries, we need continued investment in research and development for health technologies.GHTC looks forward to working with the president and his administration to drive these issues forward in 2016.

A recent clinical trial found that convalescent plasma therapy, a treatment in which the blood plasma is taken from survivors of a disease and used to treat current patients, did not prove to be effective against Ebola. The blood plasma of survivors includes antibodies against the pathogen, in this case the Ebola virus, which can boost a patient’s immune response. Convalescent plasma therapy has been used for more than 100 years, and was first used against Ebola in 1976. In the trial, plasma therapy was used to treat 84 patients, and an additional 418 patients that had been treated at the same facility served as the control group. The treatment reduced death rates by a mere 2.6 percent, and the result was not statistically significant. However, the trial did demonstrate that the collection and transfusion of blood plasma from survivors to patients was safe and feasible in low-resource settings. During the trial, the therapy did appear to be particularly effective in pregnant women and infants, however, the sample size was too small to confirm. Plasma samples from the trial will now be sent to a facility in France where researchers will assess the concentration of antibodies in the samples to determine if the quantity of antibodies affected survival rates. A recent study suggests that the antimalarial artesunate/amodiaquine (ASAQ) could be more effective against Ebola than artemether/lumefantrine (AL), an antimalarial previously used to treat Ebola, due to the diseases’ overlapping symptoms. During the outbreak, a Médecins Sans Frontières treatment center in Liberia initially used AL to treat patients, however, after running out of AL, they began to use ASAQ. The death rate for patients receiving ASAQ was 50.7 percent, compared to 64.4 percent of patients on AL. While ASAQ appears to be a promising treatment, additional trials are needed to investigate ASAQ’s efficacy in reducing Ebola mortality. Strains of the bacteria responsible for the sexually transmitted infection gonorrhea are becoming increasingly resistant to antibiotics. In the United States, one-third of gonorrhea cases are resistant to at least one antibiotic. Public officials, both in the United States and Britain, are urging doctors to follow prescription recommendations to prevent the spread of drug-resistant strains. In Britain, many doctors continue to prescribe ciprofloxacin, which has not been recommended for gonorrhea in 10 years. In the United States, doctors have historically prescribed ceftriaxone, however, between 2011 and 2013—after new guidelines led doctors to prescribe ceftriaxone in combination with azithromycin—ceftriaxone-resistant strains decreased by two-thirds from 1.4 percent to .4 percent of cases. Cow standing in a grassy field. (Photo: PATH/Eric Becker) The bacteria Mycobacterium bovis, which causes bovine tuberculosis (TB), is a rising cause of human TB, and while it’s responsible for just 1.4 percent of cases globally (and 1.5 percent of cases in America), up to 44 percent of TB-infected Latino Americans have the bovine version. Bovine TB is found in two dozen mammal species and is usually transmitted to humans through unpasteurized dairy products. In Mexico, 40 percent of dairy products are unpasteurized, and consequently the proportion of bovine TB cases among Americans are highest along the US-Mexico border. Two-thirds of bovine cases in the United States are extra-pulmonary—outside of the lungs—and are consequently undetectable by standard diagnostic techniques. The remaining third, confined to the lungs, could presumably be spread between humans through coughing or sneezing.