Noninferiority trials

[ema-adama]

Abstract

Noninferiority trials are intended to show that the effect of a new treatment is not worse than that of an active control by more than a specified margin. These trials have a number of inherent weaknesses that superiority trials do not: no internal demonstration of assay sensitivity, no single conservative analysis approach, lack of protection from bias by blinding, and difficulty in specifying the noninferiority margin. Noninferiority trials may sometimes be necessary when a placebo group can not be ethically included, but it should be recognized that the results of such trials are not as credible as those from a superiority trial.
Keywords: assay sensitivity, blinding, clinical trials, equivalence, intention-to-treat



http://www.ncbi.nlm.nih.gov/pmc/articles/PMC59590/
I am still learning the lingo, but this looks suspicious. Now we assume vaccines are safe and effective, and based on that proove that new vaccine are safe and effective?


Though Pfizer could not do full clinical trials using a placebo, the company did find in non-inferiority trials that the new vaccine is a significant improvement over its predecessor in all but one of the six additional strains.
http://www.nasdaq.com/aspx/stock-market-news-story.aspx?storyid=200911190916dowjonesdjonline000 518&title=correct-1118fda-board-considers-prevnar-vaccine-safe-effective

[Momtezuma Tuatara]

Most vaccine trials are now "non-inferior" trials.

This statement was interesting in the Nasdaq article

Vicky Debold, director of patient safety at the National Vaccine Information Center and the advisory board's consumer representative, voted against considering the vaccine safe and effective. She asked if new vaccines would be continually needed.
Parents will ask, "Is there an end to this or are we going to have to continue to deal with the emergence of antibiotic pneumococcal strains?" Debold said.

[ema-adama]

Good to know. I am trying to piece this all together - I'll get there.