Completing the Process -- Some More Testing, then Soon to Market!
by Brendan Milliner and Lisa Rotenstein
Phase 3 Trials
This phase of testing is usually much larger than the other two phases-- typically, several thousand patients will be enrolled. Phase 3 trials help to provide large-scale efficacy and side effect data so that researchers can understand how best to use the drug. They help to make sure that the drug works in a range of different patients, and doesn't cause rare side effects that might have been missed in smaller trials. Typically there are at least two phase 3 trials with similar endpoints, so that researchers can prove that the effects and safety findings weren't just a function of chance, and that the effects can be repeated. These trials are large, expensive, and are the last hurdle before sending the drug's information to the FDA for approval. Often as these studies are being conducted, additional phase 1 studies looking at drug interactions (with commonly used medications) or in special populations (those over age 65 or those with kidney disease and/or cardiovascular disease) are conducted as well for an even greater understanding of the effects of the drug across all relevant groups of potential users. For example, many people with type 2 diabetes are over 65, take several other medications for their cholesterol or blood pressure, and may have some decrease in kidney function - it is important to know how these patients will respond to a new drug for diabetes.
A Symlin trial, quite typical of phase 3 studies, looked at the long term safety of the drug in 400 type 1 and type 2 diabetic patients. It was conducted in 48 study locations around the US and looked at any adverse events that could have been associated with patients taking Symlin. It also looked at what Symlin did to A1c levels and body weight in the long term and examined issues type 1 and type 2 diabetic patients had managing their diabetes.
Submission and Approval
Upon completion of phase 3 trials, the company developing the drug must submit a New Drug Application (or NDA) to the FDA. The NDA contains information from the entire development program of the compound (preclinical and clinical), and also includes information on plans for manufacturing and marketing the drug to consumers. The company then waits for the FDA to reach a decision on whether the drug is marketable. After the FDA has accepted a filing, it sets a "PDUFA date," which is the time by which the FDA must reach a decision. The review process may take a year or longer (as is usually the case, especially in diabetes), and additional studies are sometimes required to further convince the FDA of the safety or efficacy of a candidate drug.
Typically, the FDA will convene a panel of experts to advise it based on a more detailed analysis of the data (this panel is called an Advisory Committee). See diaTribe 14's Dialogue for an interview with Rebecca Killion, the inspiring patient representative on this board. During a one-day meeting, the Committee is asked to debate specific questions put forward by the FDA and then give its final opinion by a vote. The FDA is not required to follow the recommendations of the Advisory Committee, but experience would suggest that it usually does. See NewNowNext in diaTribe issue 15 for our coverage of the Advisory Committees for two diabetes drugs that haven't yet been approved, saxagliptin and liraglutide.
If a drug is approved by the FDA, the sponsoring company may begin to sell the drug and advertise to consumers and health care professionals. In many cases, the company may be asked to conduct additional large-scale trials of the drug once it is already on the market-these are known as post-marketing trials.
Symlin still underwent several trials after its approval. A study finished in 2007, two years after the drug's approval looked at the use of Symlin in adolescents age 12 to 17 with both types 1 and 2 diabetes. Another big report finished in 2008 looked at Symlin's usage in the marketplace after it was introduced. It was observational, meaning that patient data was collected, but patients were not assigned to a specific treatment.
The approval process for diabetes drugs has become more complicated since the FDA released new guidance intended to reduce the risk of cardiovascular (CV) side effects from diabetes drugs. This new guidance is in addition to the previous FDA requirements. To rule out negative CV effects, a drug must be given to a large number of people over a long period of time (often many years), and this type of trial can be expensive and difficult for drug companies to complete before the drug is approved and making money. There has been a great deal of controversy surrounding this issue in the diabetes community, because of fears that the new restrictions will make companies less willing to develop new diabetes drugs that could be helpful for patients. Click here to see the letter sent to companies by the FDA. Particularly following new data given at this year's ADA, we think the requirement for pre-approval screening is overly restrictive and may delay innovative new treatments for people with diabetes.
How to Get Involved - Participating in a Clinical Trial - In the Next Segment!
This story is brought to you by diaTribe, an independent, advertising free, e-newsletter focused exclusively on products and research for people with diabetes. Jeff Hitchcock has been on diaTribe's advisory board since its inception. Kelly Close, the editor-in-chief, has had type 1 for nearly 25 years. diaTribe is for everyone eager to learn about the latest advances in diabetes management focusing on research and product news.
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Last Updated: Tuesday December 08, 2009 11:34:21
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