WASHINGTON - Senators David Pryor and William Cohen have abandoned, at least for now, their campaign to test the "reasonableness" of the pricing of Betaseron, Chiron Corp.'s new drug for multiple sclerosis.

In an Aug. 30th letter to Berlex Laboratories, Pryor, the Arkansas Democrat who is chairman of the Senate Special Committee on Aging, and Cohen, the Maine Republican who is the committee's ranking minority member, expressed disappointment that the price was not set lower. Berlex, which is marketing Betaseron, has set the price and established programs to insure patient access to the drug.