BOEHRINGER INGELHEIM PERSANTINE RELABELING ANNOUNCEMENTS

BOEHRINGER INGELHEIM PERSANTINE RELABELING ANNOUNCEMENTS are unacceptable to FDA because they mislead "health care professionals to believe that Persantine will soon be the only dipyridamole product available and that use of any other available product for the treatment of angina pectoris will soon be unlawful," FDA Office of Drug Standards Director Peter Rheinstein, MD, told the firm in an Aug. 24 regulatory letter. The regulatory letter objects to a series of letters the company issued to doctors, pharmacists, third-party-payors/formularies and buyers in February. The letters inform health professionals that Persantine has been relabeled to delete the angina indication, "while a new indication for use as an adjunct to coumarin anticoagulants in the prevention of postoperative thromboembolic complications of cardiac value replacement has been added." The letters also point out that Persantine is the only dipyridamole product to be approved for the new indication and that "the agency has now determined that . . . studies do not adequately demonstrate the effectiveness of dipyridamole in angina pectoris and has asked that the angina pectoris indication be removed from the labeling for dipyridamole." The reg letter maintains that the companies promotional letters are "false and/or misleading . . . by attempting to convince health care providers that FDA has made a final determination that dipyridamole is ineffective for the treatment of angina pectoris." FDA assumes, Rheinstein said, "that your firm is well aware of the fact that until such time as the agency denies or conducts [DESI hearings on the angina indication], all products are lawfully permitted to remain on the market with their current labeling." The regulatory letter also objects to the promotional letters' implication that "Persantine (dipyridamole) will soon be the only legally available product of dipyridamole on the market by virtue of the new indication for adjunctive use with coumarin postoperatively." The regulatory letter explains that Persantine may never have a period of exclusive marketing because of the typically lengthy DESI review hearing process. "Although your product may carry the exclusive indication until Dec. 22, 1989," Rheinstein said, "the hearing process for other DESI drugs has in the past taken a significant period of time before a final determination is made. It is very possible that the period of exclusivity will be expired before the final effectiveness of the drug in angina has been made." The agency was also critical of the suggestion in Boehringer Ingelheim's letter to buyers that supplies of Persantine be increased. "If Boehringer Ingelheim believes that dipyridamole is ineffective for angina pectoris, we fail to understand why you would urge health care professionals to increase their inventories. It would seem that the new approved indication for Persantine would significantly reduce the number of patients who might benefit from your product," Rheinstein said. "It appears that your firm is anticipating that, should Persantine become the only dipyridamole product on the market, there would be a significant use beyond the approved new indication (i.e., chronic use in angina pectoris)." FDA is requesting the company to "immediately cease to disseminate any materials which suggest that Persantine will soon be the only dipyridamole product on the market, or that any other existing dipyridamole product, which is the subject of an approved NDA, is unlawful or ineffective for its labeled use." The agency is also asking the firm to issue corrective letters "to each of the health care professionals who may have received" the February letters. The firm is instructed to inform the agency of its intentions to take corrective action within 10 days of receipt of the regulatory letter. FDA said it anticipates a response by Sept. 11.