Ebola Vaccines, Treatments Ramp Up for Clinical Trials

Several vaccine candidates are moving into larger clinical trials, supported by  government and industry efforts to address manufacturing and research challenges. Anthony Fauci, director of the National Institute for Allergy and Infectious Disease (NIAID) at the National Institutes of Health (NIH) is collaborating with manufacturers to launch phase 2-3 trials of two vaccines in Liberia to gain further evidence of safety, immune response and efficacy. The trials should begin in a few weeks, pending final approval by the Food and Drug Administration and by the Liberian government, Fauci explained at a press briefing that highlighted efforts by the Obama administration to utilize American scientific and financial resources to combat the ebola outbreak.

Evidence from early phase 1 studies indicates sufficient safety and immune response for vaccines being developed by GlaxoSmithKline and by a partnership of Merck and NewLink Genetics. The next step, said Fauci, is to determine efficacy of both vaccines through a 3-arm randomized, double-blinded trial:  treatment arms for the two vaccines and one with placebo injection. At the same time, the Centers for Disease Control and Prevention (CDC) is planning a phased-introduction study in Sierra Leone, using one vaccine candidate to compare the effect of early vs. later vaccination.

Meanwhile, the Biomedical Advanced Research and Development Authority (BARDA) in HHS is working with vaccine makers to support production for clinical trials and anticipated commercialization. One goal is to validate and optimize assays to facilitate comparability studies for eventual licensure of the by Glaxo and Merck vaccines, as well as one being developed by Johnson & Johnson/Bavarian Nordic. A related effort, BARDA director Robin Robinson added, is to devise vaccine formulations that will not require freezing, but can be kept in refrigerators and transported even without cold storage.

This update on U.S.-supported ebola vaccine development efforts follows an announcement last week by the European Union’s Innovative Medicines Initiative of its expanded investment in ebola vaccine testing and distribution. The program has allotted about $250 million for its Ebola+ program, which includes several projects that support development of the Johnson & Johnson/Bavarian Nordic product.

Boosting Zmapp

BARDA also is advancing production of the leading ebola therapeutic candidate, Zmapp, to support clinical trials and future large-scale production. So far, Zmapp producer Kentucky BioProcessing has completed 3 of 6 production campaigns, benefitting from strategies to boost yield to provide several hundred doses for initial trials. These supplies have been filled into containers at Baxter Healthcare, a member of BARDA’s fill and finish manufacturing network, and are undergoing lot release testing for FDA review. BARDA is working with several additional biopharma companies that use tobacco plants for drug production to expand possible supply sources. And the agency is supporting efforts by Regeneron and Genentech to produce Zmapp in mammalian CHO cells, using a specialized cell line due to difficulties growing Zmapp in more usual biotech production systems.

Ramped-up Zmapp production now can supply phase 1 and phase 2 clinical trials, which NIAID is helping to design for initial testing in the U.S. and Liberia. Fauci noted the importance of conducting rigorous clinical trials, and of addressing relevant ethical issues and engaging the local community fully in the process. Such studies, he noted, will require “multiple reviews and approvals in the U.S. and in Liberia.”