Opinion ID: 76908
Heading Depth: 2
Heading Rank: 3

Heading: Challenge/De-challenge/Re-challenge Methodology

Text: 110 Finally, in reaching his opinions that Metabolife 356 in fact caused each of the Plaintiff's injuries, Hakim claims to have used a challenge/de-challenge/re-challenge methodology. To explain this methodology during the Daubert hearing, Hakim testified that while treating Plaintiff Thornburg he noticed a pattern. When she took Metabolife 356, she had strokes, but when she did not take it, she did not have strokes until she started it again. In essence, the stroke occurred during the challenge stage when she took the drug. The de-challenge occurred when she came off the drug and did not have a stroke, and the re-challenge occurred when she started taking the drug again and had another ischemic event. But this theory has a serious flaw. 111 In April of 2000, Hakim decided that Metabolife had caused Thornburg's strokes and told her to stop taking it. In June of 2000, after being off Metabolife for two months, she had another ischemic event. In other words, according to his challenge/de-challenge/re-challenge theory, she had another ischemic event during the de-challenge phase. During the hearing, Hakim attempted to explain away that inconsistency by saying that the ischemic event during the de-challenge phase occurred because of the lingering effects of ephedrine. To bolster this opinion he resorted to another medical analogy — the analogy of alcohol causing liver damage. Nothing in the evidence, however, supports the dubious analogy that the ephedrine causes strokes and heart attacks like alcohol causes cirrhosis of the liver. 112 Furthermore, [t]he temporal connection between exposure to chemicals and an onset of symptoms, standing alone, is entitled to little weight in determining causation. Moore, 151 F.3d at 278. It is also subject to the problem of assuming what the witness is trying to prove. This pitfall will most likely arise when, as here, there are not scientific controls in place. 113 As this court explained in Rider , de-challenge/re-challenge tests are still case reports and do not purport to offer definitive conclusions as to causation. 295 F.3d at 1200. Their value is directly related to the degree of scientific control used in the testing. Because there were insufficient controls employed in Hakim's crude challenge/de-challenge/re-challenge methodology, and Hakim's own testimony established that Thornburg suffered ischemic events when she was not taking Metabolife 356, this methodology does not provide the necessary indicia of reliability to his final opinions on causation.