Viagra, Part II — MDL Court Sees The Light – Bad Data Trump Nuances of Statistical Inference

In the Viagra vision loss MDL, the first Daubert hearing did not end well for the defense.  Judge Magnuson refused to go beyond conclusory statements by the plaintiffs’ expert witness, Gerald McGwin, and to examine the qualitative and quantitative evaluative errors invoked to support plaintiffs’ health claims.  The weakness of McGwin’s evidence, however, appeared to  encourage Judge Magnuson to authorize extensive discovery into McGwin’s study.  In re Viagra Products Liab. Litig., 572 F. Supp. 2d 1071, 1090 (D. Minn. 2008).

The discovery into McGwin’s study had already been underway, with subpoenas to him and to his academic institution.  As it turned out, defendant’s discovery into the data and documents underlying McGwin’s study won the day.  Although Judge Magnuson struggled with inferential statistics, he understood the direct attack on the integrity of McGwin’s data.  Over a year after denying defendant’s Rule 702 motion to exclude Gerald McGwin, the MDL court reconsidered and granted the motion.  In re Viagra Products Liab. Litig., 658 F. Supp. 2d 936, 945 (D. Minn. 2009).

The basic data on prior exposures and risk factors for the McGwin study was collected by telephone surveys, from which the information was coded into an electronic dataset.  In analyzing the data, McGwin used the electronic dataset and not the survey forms.  Id. at 939.  The transfer from survey forms to electronic dataset did not go smoothly; about 11 patients were miscoded as “exposed“ when their use of Viagra post-dated the onset of NAION. Id. at 942.  Furthermore, the published article incorrectly stated personal history of heart attack as a “risk factor ”; the survey inquired about family not personal history of heart attack. Id. at 944.

The plaintiffs threw several bombs in response, but without legal effect.  First, the plaintiffs claimed that the study participants had been recontacted and the database had been corrected, but they were unable to document this process or the alleged corrections.  Id. at 433.  Furthermore, the plaintiffs could not explain how, if their contention had been true, McGwin would have not committed serious violations of his university’s institutional review board’s regulations with respect to deviations from the original protocol.  Id. at 943 n.7.

Second, the plaintiffs argued that the underlying survey forms were “inadmissible ” and thus the defense could not use them to impeach the McGwin study.  Some might think this a duplicitous argument, utterly at odds with Rule 703 – rely upon a study but prevent use of underlying data and documents to explain that the study does not show what it purports to show.  The MDL court spared the plaintiffs the embarrassment of ruling that the documents on which McGwin had based his study were inadmissible, and found that the forms were business records and admissible under Federal Rule of evidence 803(6).  The court could have gone further to point out that McGwin’s reliance upon hearsay in the form of his study, McGwin 2006, opened the door to impeaching the hearsay relied upon with other hearsay.  See Rule 806.

When defense counsel sat down with McGwin in a deposition, they found that he had not undertaken any new analyses of corrected data.  Plaintiffs’ counsel directed him not to do so.  Id. at 940-41.  But then after the deposition was over, McGwin submitted a letter to the journal to report a corrected analysis.  Pfizer’s counsel obtained the letter in response to their subpoena to McGwin’s university, the University of Alabama, Birmingham.  Mirabile dictu; now the increase risk appeared limited to only to the defendant’s medication, Viagra!

The trial court was not amused.  First, the new analysis was no longer peer reviewed, and the court had placed a great deal of emphasis on peer review in denying the first challenge to McGwin.  Second, the new analysis was no longer that of an independent scientist, but was conducted and submitted as a letter to the editor, while McGwin was working for plaintiffs’ counsel.  Third, the plaintiffs and McGwin conceded that the data were not accurate.  Last, but not least, the trial court clearly was not pleased that the plaintiffs’ counsel had deliberately delayed McGwin’s further analyses until after the deposition, and then tried to submit yet another supplemental report with those further analyses. In sum:

“the Court finds good reason to vacate its original Daubert Order permitting Dr. McGwin to testify as a general causation expert based on the McGwin Study as published. Almost every indicia of reliability the Court relied on in its previous Daubert Order regarding the McGwin Study has been shown now to be unreliable.  Peer review and publication mean little if a study is not based on accurate underlying data. Likewise, the known rate of error is also meaningless if it is based on inaccurate data. Even if the McGwin Study as published was conducted according to generally accepted epidemiologic research and did not result from post-litigation research, the fact that the McGwin Study appears to have been based on data that cannot now be documented or supported renders it inadmissibly unreliable. The Court concludes that under Daubert, Dr. McGwin’s opinion, to the extent that it is based on the McGwin Study as published, lacks sufficient indicia of reliability to be admitted as a general causation opinion.”

Id. at 945-46.  The remaining evidence was the Margo & French study, but McGwin had previously criticized that study as lacking data that ensured that Viagra use preceded onset of NAION.  In the end, McGwin was left with bupkes, and the plaintiffs were left with even less.

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McGwin 2006 Was Also A Pain in the Rear End for McGwin

The Rule 702 motions and hearings on McGwin’s proposed testimony had consequences in the scientific world itself.  In 2011, the British Journal of Ophthalmology retracted McGwin’s 2006 paper.  “Retraction: Non-arteritic anterior ischaemic optic neuropathy and the treatment of erectile dysfunction, ” 95 Brit. J. Ophthalmol. 595 (2011).

Interestingly, the retraction was reported in the Retraction Watch blog, “Retractile dysfunction? Author says journal yanked paper linking Viagra, Cialis to vision problem after legal threats.”  The blog treated the retraction as routine except for the hint of “legal pressure”:

“One of the authors of the paper, a researcher at the University of Alabama named Gerald McGwin Jr., told us that the journal retracted the article because it had become a tool in a lawsuit involving Pfizer, which makes Viagra, and, presumably, men who’d developed blindness after taking the drug:

‘The article just became too much of a pain in the rear end. It became one of those things where we couldn’t provide all the relevant documentation [to the university, which had to provide records for attorneys].’

Ultimately, however, McGwin said that the BJO pulled the plug on the paper.”

Id. The legal threat is hard to discern other than the fact that lawyers wanted to see something that peer reviewers almost never see – the documentation underlying the published paper.  So now, the study that formed the basis for the original ruling against Pfizer floats aimlessly as a derelict on the sea of science.  McGwin is, however, still at his craft.  In a study he published in 2010, he claimed that Viagra but not Cialis use was associated with hearing impairment.  Gerald McGwin, Jr, “Phosphodiesterase Type 5 Inhibitor Use and Hearing Impairment,” 136 Arch. Otolaryngol. Head & Neck Surgery 488 (2010).

Where are Senator Grassley and Congressman Waxman when you need them?

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