PFS= Pergression Free Survival
The Pink Sheet Daily. 2009 Sept 16, MJ Laffler
FDA Office of Oncology Drug Products Director Richard Pazdur plans to convene an advisory committee meeting to clarify standards for use of progression-free survival data, a move prompted by industry's aggressive adoption of the surrogate endpoint and, more broadly, the gradual decline in the level of drug benefit that sponsors seek to use in support of a cancer drug approval.
Though Pazdur wouldn't predict the timing of a meeting - beyond "soon" - he confirmed that it is an important issue that should be the topic of an upcoming meeting of the Oncologic Drugs Advisory Committee.
Industry Has Been Aggressive With PFS
In the last decade, there has been an extensive shift in oncology trials, with sponsors embracing the opportunity for earlier, arguably easier approval. The trend arose after FDA started accepting PFS as an early marker thought to be predictive of an eventual survival advantage - prompted by the urgent need for treatment options and availability of the accelerated approval pathway.
Allowing PFS to support accelerated approvals and eventually to support full approval did result in some impressive advances in medical oncology reaching patients years sooner than would have otherwise been possible. FDA has been careful to require trials to continue on in the post-market setting to demonstrate an overall survival finding, and the agency has upheld overall survival as the gold standard of efficacy evidence.
But the widespread reliance on PFS endpoints also created some sticky regulatory issues.
Source:FDA Will Revisit Appropriate Use of PFS Endpoints at Advisory Committee
As I see it, this PFS data can be used as a screening tool that shows that the drug/therapy has some response on the tumor regression/stabilization. It can be used as a predictive tool. The sooner we the patients can get our hands on the drug, the more lives may be saved. Take for instance tremelimumab and ipilimumab (Anti-CTLA-4 Blockage), it has shown great promise.
"At a meeting of cancer specialists last June Bristol-Myers and Medarex reported their drug shrank tumors in 46, or 13%, of 356 melanoma patients. The Pfizer antibody shrank melanomas in 7 of 84 patients in a midstage trial. The success rates were modest, but cancer doctors say that some patients may have had delayed responses. In some people tumors started to regress months after they had been declared treatment failures, says Bristol-Myers Vice President Renzo Canetta.
UCLA's Ribas calls the response rates "very low" and cautions that the anti-CTLA-4 drugs are just a first step. But even if the drugs improve survival only minimally, they are likely to be approved, he says.
One reason for the limited response rate may be that some patients' T cells do a poor job of recognizing melanoma. To improve this situation, researchers are combining new antimelanoma vaccines with anti-CTLA-4 drugs. The idea is that the vaccines will train T cells to spot cancer, while the antibody will make sure the T cells remain activated long enough to do their dirty work."
excerpts from FORBES.COM
Targeting Melanoma
author: Robert Langreth 10.15.07
Take Care,
Jimmy B
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