Perspectives on the design and analysis of prelicensure trials: bridging the gap to postlicensure studies.
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Recently, there has been growing concern regarding vaccine safety. Vaccines have led to the eradication of many serious diseases. Accordingly, there is less familiarity with the consequences of diseases and increasing concern with potential rare adverse events. The availability of clinical information systems within health maintenance organizations makes assessment of safety in larger cohorts, with power to assess rare adverse events, possible. However, no trial, no matter how large, can rule out all possible adverse events. There will always be the possibility that a rarer adverse event-just beyond the power of detection of a given trial-may occur. It is proposed that prelicensure trials in 10,000-40,000 children are now feasible. However, it will be necessary to develop an analytic continuum in which prelicensure studies are followed up with postmarketing assessments. Accordingly, the rapid identification of intussusception as a complication of rotavirus vaccination should not be seen as a failure of prelicensure studies but rather as a positive example of an effective integrated safety assessment program. (+info)
The success of immunizations in nearly eliminating many vaccine-preventable diseases has resulted in an increase in the need to study risks from vaccines, combination or otherwise. The well-known limitations associated with prelicensure trials have led many to hope that postlicensure studies can address safety issues. This article reviews measures that have been or should be taken to meet this expectation: establishment of clinical immunization safety assessment centers, standardization of case definitions for vaccine adverse events, use of the Vaccine Identification Standards Initiative to improve the accuracy and efficiency with which vaccination records are transferred, integration of vaccine safety monitoring into immunization registries, establishment (and enlargement) of the Vaccine Safety Datalink project, use of innovative analytic tools for better signal detection, and implementation of various methods to overcome confounding by contraindication. Only by investing in vaccine safety infrastructure at a level commensurate with investments in vaccine development can we hope to retain the public's confidence in immunization. (+info)
Perspectives on the manufacture of combination vaccines.
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Evolving regulatory requirements in the United States and Europe create major challenges for manufacturers tasked with production of vaccines that contain > or =9 separate antigens capable of protecting against infectious diseases, such as diphtheria, tetanus, pertussis, polio, hepatitis B, and Haemophilus influenza b, in a single shot. This article describes 10 steps that can facilitate the process of licensing these complex vaccines. It also points out problems associated with the use of animal tests for the crucial step of potency testing for batch release caused by the inherent variability of such tests and the difficulties of interpreting their results. (+info)
Considerations for combination vaccine development and use in the developing world.
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As more vaccines are developed and become available, combination vaccines will provide a way of delivering multiple antigens to avoid multiple injections and complications in the regular immunization schedules. The advantages of combination vaccines are that they decrease the discomfort of vaccine recipients and parents and also reduce the delivery cost of vaccines. We address some of the issues related to the use of combination vaccines in the developing world. Which vaccines are needed? Do developing countries have the appropriate infrastructure to deliver them? Can vaccines become affordable for countries with low incomes? And what is really needed to achieve the goal of providing developing countries with new vaccines of epidemiologic significance in a timely fashion? (+info)
Manufacturing issues related to combining different antigens: an industry perspective.
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Despite the growing demand for combination vaccines, many challenges have been encountered in developing them. It is difficult to predict the physical compatibility and stability of antigens in combination, because these characteristics are highly dependent on vaccine excipients. Clinical evaluation of potential modifications of efficacy of antigens in combination may be alleviated by use of appropriate animal models. Manufacturing issues, such as batch-release testing, storage of intermediate products, and the shift to preservative-free products, are of particular concern because they have the potential to affect the supply chain. Managing changes in the manufacture of one antigen that is a component of several different combination vaccines is also difficult. However, most potential issues can be resolved through the simplification of regulatory processes and harmonization of requirements, such as the acceptance of comparability protocols and antigen master files. Continued collaboration between industry and authorities is necessary to develop effective means of handling all submissions pertaining to combination vaccines. (+info)
Manufacturing issues with combining different antigens: a regulatory perspective.
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The regulation of biological products is conducted within the framework Title 21 of the US Code of Federal Regulations (CFR). These regulations describe product and clinical testing requirements for drugs and biological products, as well as the requirements for licensure of such products. The requirements outlined in the CFR also apply to combination vaccines. In addition, the Center for Biologics Evaluation and Research has issued a Guidance to Industry document that discusses the manufacturing, testing, and clinical evaluation of combination vaccines. However, as the complexity of mixing the different antigens increases, the challenges associated with product development (e.g., demonstration of comparability of the components and lot consistency) require early interactions with the US Food and Drug Administration. The many areas of difficulty in the arena of combination vaccine development underscore the need for continued reevaluation of current guidance documents in addressing the increasing complexity of vaccines. (+info)
Vaccine industry perspective of current issues of good manufacturing practices regarding product inspections and stability testing.
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I address 2 important topics of current good manufacturing practices as they apply to vaccine products: product inspections and stability testing. The perspective presented is that of regulated industry. There are 2 major categories of product/facility inspections: those occurring before licensure of a vaccine product and those occurring after a vaccine product is licensed. The logistics and focus of each inspection type, the preapproval inspection, and the required biennial inspection are discussed, as are guidance and recommendations for achieving successful inspections. The requirements, guidance, and recommendations regarding the type, amount, and extensiveness of stability data for vaccine products are presented. The discussion details the potential differences in the amount and type of data required for products that are not yet licensed versus marketed products. Guidance, from a regulated industry perspective, regarding the design and implementation of a successful stability program is also discussed. (+info)
Potency tests of combination vaccines.
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Combination vaccines differ from single-component vaccines in composition and in how they are manufactured, which poses significant challenges to implementing effective quality-control tests, including measurement of potency. Because each combination vaccine is unique, existing guidelines often fail to provide sufficient information to overcome the inevitable problems encountered when developing and implementing potency tests. Success depends on careful consideration of scientific and regulatory issues. Significant problems may occur if potential interactions between different components in the vaccine are not taken into account during product and test development. Thorough analysis of critical assay parameters and attention to scientific and statistical justifications for the test increase the likelihood of its acceptance. Practical approaches based on experience include rational design of validation studies, complete evaluation and documentation of the potency tests under the conditions in which they are to be applied, and establishing the relationship between production lots of vaccine and lots used in clinical trials. (+info)