October 23, 2016

Research Roundup: Pharmaceutical waste and superbugs, resistance to insecticides, and vaccines for crises

Senior Program Assistant

While overuse of antibiotics is often cited as a leading contributor to the development and spread of drug-resistant bacteria, recent studies reveal that pollution from antibiotic manufacturing plants in India and China is also playing a role. The wastewater released from these manufacturing facilities contains active antimicrobial ingredients, and in some cases, higher concentrations of these compounds are found downstream from these facilities than is found in patients currently taking antibiotics. One type of bacteria can acquire from another type of bacteria genes that confer resistance to a certain drug. Consequently, resistance is spreading rapidly in wastewater treatment plants in China—for every bacterium that goes into the plants, four to five drug-resistant bacteria come out. To combat this dangerous trend, advocates are calling on the US government, drugmakers, pharmaceutical retailers, and consumers to put pressure on these plants to stop polluting using diplomatic tactics and purchasing power.

Meanwhile, new data from the European Medicines Agency indicate that while sales of antibiotics for use in livestock has declined modestly in the European Union, sales have increased for many of the world’s strongest antibiotics, including last-resort treatments and those deemed by the World Health Organization (WHO) to be “critically important in human medicine.”

Mother and child on bed draped with bednet (Photo: David Jacobs)
Mother and child on bed draped with bednet (Photo: David Jacobs)

Between 2000 and 2015, insecticides prevented nearly 500 million deaths from malaria, however, this remarkable progress could be upended as mosquitoes develop resistance to pyrethroids, the most commonly used class of insecticides. Pyrethroids have been around for nearly 40 years, and while resistance to this class first appeared in 1993, it has been growing rapidly over the past decade, which has resulted in increased transmission of the parasite in some countries. The pipeline for new insecticides is limited, particularly those that are safe for use in bednets. IVCC, a public-private partnership and member of GHTC, is catalyzing research to both develop novel insecticides and products that combine pyrethroids with other agents to combat growing resistance. The organization has partnered with several pharmaceutical companies and is screening their libraries of more than 4 million chemical compounds to identify the three most promising, which they will then test to determine not only safety and efficacy, but also whether they are long lasting (i.e., effective for at least three years and able to withstand 20 rounds of washing). Other entities have created bednets that combine pyrethroids with pyriproxyfen—which sterilizes the mosquitoes—and piperonyl butoxide—which could make resistance mosquitoes vulnerable to pyrethroids again. For the former, results from an evaluation will be released shortly, and for the latter, results of small trials have been encouraging, but larger, more rigorous trials are needed.

The WHO recently convened pharmaceutical companies and humanitarian organizations with the goal of establishing a mechanism to facilitate the sale of low-cost vaccines during emergencies. Under the program, pharmaceutical companies would pledge to provide predetermined vaccines at the lowest price possible during crises such as natural disasters or wars. Currently, many of the targeted drugmakers have agreements with Gavi, the Vaccine Alliance, through which vaccines are purchased in high volumes at these rock-bottom prices. However, the proposed mechanism would limit sales to nonprofits, rather than governmental bodies, to ensure that the vaccines procured would only be deployed as part of a crisis response. GlaxoSmithKline has already agreed to participate, providing its vaccine against pneumonia—the leading cause of death for children under five—at a reduced price during emergencies. The WHO is working to engage additional drugmakers as it seeks to expand the mechanism to cover vaccines against 23 different diseases, including cholera, measles, yellow fever, and hepatitis.