SELDANE CARDIOVASCULAR EFFECTS WILL BE TOPIC OF FDA ADVISORY COMMITTEE

SELDANE CARDIOVASCULAR EFFECTS WILL BE TOPIC OF FDA ADVISORY COMMITTEE meeting scheduled for June 11-12. A cryptic May 15 Federal Register notice says that FDA's Pulmonary-Allergy Drugs Advisory Committee will discuss "the cardiovascular effects of terfenadine (Seldane)." The labeling for Marion Merrell Dow's nonsedating antihistamine notes that adverse reactions to terfenadine include arrhythmias, such as ventricular tachyarrhythmia and tachycardia. The advisory committee's focus on Seldane's cardiovascular effects may have an impact on pending NDAs for Seldane D and Seldane OTC. Marion Merrell Dow Chairman Joseph Temple recently alluded to the approval delays. He told a May 8 conference sponsored by Alex. Brown that "unlike what we said right after the merger last summer, we are taking what we feel is a really conservative position by saying that neither Seldane D nor Seldane OTC will have sales in 1990." Temple said "we will not guess the timing of the FDA approval" for Seldane OTC (the NDA was submitted in August 1988). However, he noted: "We're working hard here at home to be sure that we are ready when we do get the approval." Other topics on the June 11 advisory committee agenda will be the "combination of newer antihistamines and decongestants." Combos which could come up in such a discussion include Seldane D (terfenadine with pseudoephedrine) and Janssen's Hismanal D (astemizole/pseudoephedrine SR). Schering also has Claritin D (loratadine plus decongestant) in development. The single ingredient antihistamine in that product has not yet been approved. On June 12, the committee will discuss: "considerations for trials to show equivalency for generic inhaled bronchodilators and new actuators"; an "update on chlorofluorohydrocarbons"; and the "labeling of antihistamines in relation to asthmatic patients." In December, Schering filed a petition asking FDA not to approve any ANDAs that are pending or that may be filed for "nonsystemically absorbed" drugs, including topicals, inhaled bronchodilators and inhalation solutions ("The Pink Sheet" Dec. 11, T&G-12). The company's request was based on the ANDA regs' wording, which require generic drugs to show no significant difference in "rates and extent of absorption...under similar experimental conditions" in order to be deemed bioequivalent. One of the presenters during the discussion on prescribing antihistamines for asthmatics is likely to be William Pierson, MD, University of Washington, a professor of pediatrics and environmental health. At a May 15 conference sponsored by "F-D-C Reports," Pierson said he planned to make a presentation to the Pulmonary-Allergy Advisory Committee "in three weeks to step up to the fact that antihistamines, as a matter of fact, may be beneficial in asthma." Pierson called the fact that antihistamines are contraindicated for asthmatics "a scientific myth that has astounded us in its survivability with no data." The contraindication, he observed, was based on a belief during early development of antihistamines that they had some anticholinergic or atropine-like activity. In fact, Pierson said, "antihistamines ...appear not only to have no adverse effect upon asthma, there are a multitude of studies now that have been done around the world that show that actually they are modest bronchodilators." Pfizer is believed to be conducting clinicals for one nonsedating antihistamine, cetirizine, for a pollen asthma indication. Antihistamines should be considered "number four or five" in line as a therapy for asthma, Pierson suggested. The importance of antihistamine "is the upper airway. It's clear now," Pierson told the conferees, "that chronic upper airway inflammation, namely allergic rhinitis and/or sinusitis, will cause destabilization of the lower airway, so you will never get a patient's asthma under control if you don't take care of [his or her] sinuses." The conference was sponsored by International Business Communication and F-D-C Reports, Inc. At the June 11 session, the Pulmonary-Allergy Drugs Advisory Committee is also slated to discuss the NDA for Fison's nedocromil sodium (Tilade), a cromolyn sodium analog. Nedocromil, a mast cell stabilizer, is the British firm's second generation product to its Intal and Nasalcrom cromolyn sodium products.