tailieunhanh - Essentials of Clinical Research - part 4

Đó là vị trí của FDA rằng Quốc hội có ý định yêu cầu ít nhất hai nghiên cứu đầy đủ và được kiểm soát tốt, mỗi thuyết phục riêng của mình, để thiết lập hiệu quả. Hiện đã có một số tính linh hoạt tiếp theo của FDA về vấn đề trên vì nó áp dụng cho một loại thuốc cụ thể trong phát triển. | 6 The United States Federal Drug Administration FDA and Clinical Research 101 which it could be fairly and responsible concluded by such experts that the drug will have the effect it purports or is represented to have under the conditions of use prescribed recommended or suggested in the labeling or proposed labeling thereof. The argument that ensued from this definition centered on what the specific quality of evidence was in order to establish efficacy. It was the FDA s position that Congress intended to require at least two adequate and well-controlled studies each convincing on its own to establish efficacy. There has been some subsequent flexibility by the FDA in regard to the above as it applies to a specific drug in development. In some cases for example the FDA has relied on information from adequate and well-controlled studies published in the literature. In other cases where it would be difficult to perform a second study due to ethical concerns the result of a single study could be accepted as long as it was of excellent design provided highly reliable and statistically strong - p - evidence of important clinical benefit-such as survival . The requirement of more than 1 adequate and well-controlled investigation reflects the need for independent substantiation of experimental results and refers back to the question posed in Chapter 3 that asked why studies can presumably be of similar design and yet lead to different results. Indeed the FDA realized that any clinical trial may be subject to unanticipated undetected systematic biases that may be operative irrespective of the best intentions of sponsors and investigators. They also note that the inherent variability in biological systems may produce a positive trial by chance alone. In addition results may be dependent on specific issues related to the site or the investigator . concomitant treatments diets etc. that may impact the generalizability of the results. Finally and fortunately rarely .