The European Medicines Agency (EMA) has released a new guideline to instruct sponsors of clinical trials on best practices for assessing antibody-based products used to prevent the hepatitis B virus.
The 2 December 2012 draft guideline, On the Clinical Investigation of Hepatitis B Immunoglobulins, is specifically aimed at vaccines, which EMA explains are an effective method for protecting uninfected, healthy individuals against infection by the hepatitis B virus. They can also be used in cases of accidental exposure to the virus, such as a healthcare practitioner being stuck by a dirty needle, and as an ongoing treatment measure if a patient does not exhibit an immune response to the vaccine but requires ongoing protection from the virus.
The hepatitis B virus is known to cause inflammation of the liver, and is most commonly spread by the transmission of bodily fluids or blood. Other symptoms include nausea, vomiting, fever and in severe cases, cirrhosis of the liver.
EMA's guideline on product development frequently delves into specifics. Pharmacokinetic testing, for example, "Should be examined in at least 20 healthy adult volunteers negative for [hepatitis B and its antigens]," EMA explained. Products should also meet the batch-consistency standards established by the European Pharmacopoeia (Ph.Eur.), and consistency must be documented in any product submission to EMA.
For clinical trials, a sufficient number of enrolled patients must be used to ensure the generation of confirmatory data. EMA said it recommends at least 25 patients who have undergone liver transplant for hepatitis B-caused liver failure be enrolled in the trial.
Sponsors should be prepared to generate baseline data regarding the status of the patient in regard to the disease, any co-infections with other viruses, exposure to immunosuppressive and antiviral therapies, time elapsed between the transplant of a liver and the start of prophylaxis and the concentration of hepatitis B virus in a patients' bloodstream. EMA explained that the endpoint of a trial should be the "proportion of patients who develop recurrent hepatitis B," while secondary endpoints include time to recurrence, overall survival and the remaining titre of circulating hepatitis B.
Other parts of the guideline are less specific to Hepatitis B antibodies, such as required adverse event reporting to regulatory authorities, reporting manufacturing changes and the submission of a risk management plan. Those portions of the guideline serve as reminders to consult other guidelines for additional information.
Comments on the draft guideline are due to EMA by 3 June 2013, and may be sent to BPWPSecretariat@ema.europa.eu