The deceased plaintiff in a lawsuit alleging a Wyeth-made hormone replacement therapy drug caused her death from breast cancer has a surviving identical twin who has not had breast cancer.

Both the plaintiffs and the defense attorneys sought to leverage to their advantage the fact that Cheryl Foust’s twin sister, Carol, was present and in good health in a Philadelphia Common Pleas courtroom Wednesday. Opening arguments were held in Foust v. Wyeth. Senior Judge Esther R. Sylvester is presiding over the trial.