A federal appeals court has given a key victory to cigarette makers by ruling that the First Amendment does not give the public the right to know before a trial what information the industry provided plaintiffs' lawyers in the discovery process.

The Third U.S. Circuit Court of Appeals in Philadelphia reversed and sent back a decision by U.S. District Judge H. Lee Sarokin in a smoker's-death case in which product-liability damages are sought from the Liggett Group Inc.; Philip Morris Inc., and Loew's Theatres Inc., the successor to Lorillard.

"We're delighted, obviously, that the Third Circuit agreed with our position," said Murray H. Bring of Arnold & Porter, Philip Morris' Washington law firm.

"The decision makes it possible for us to have a fair trial before a court and jury, and not to have a piecemeal discussion of the issues in which snippets of information from various documents are taken out of context and mischaracterized," Bring said.

Marc Z. Edell, a lawyer for the late Rose D. Cippolone, a 40-year smoker, could not be reached.

The ruling orginated in Newark in March 1985, when Federal Magistrate Robert E. Cowens, in charge of pretrial discovery, signed an "umbrella" order protecting the confidentiality of the hundreds of thousands of pages of documents the defendants were producing.

Judge Sarokin overturned the protective order four months later. He held that documents other than those containing trade secrets could be made public because the companies are not entitled to the protection accorded documents "which are truly secret," such as marketing strategies. He said Cowens' order interfered with the First Amendment by extending protection to materials bearing on the companies' "part, if any, in concealing or misrepresenting information regarding the risks of smoking."

A three-judge Third Circuit panel heard argument on the companies' appeal in September and ruled unanimously Wednesday.

The stock market reacted favorably to the ruling. Philip Morris rose $4.88 yesterday, closing at $113.63 on volume of 1.5 million shares. R. J. Reynolds rose $2.50, closing at $41.50 on 1.9 million shares.

In the opinion for the appellate panel, Judge Edward R. Becker said Sarokin misread a 1984 Supreme Court decision (Seattle Times Co. v. Rhinehart) that left "no room for lower courts to consider First Amendment factors in fashioning or reviewing" protective orders.

The decision stressed that pre-trial discovery is "not a forum traditionally open to the public," and required Sarokin "merely to inquire whether the defendants had demonstrated good cause for the protective order," Becker wrote.

The panel remanded the case to Sarokin for "reconsideration of good cause," that is, whether Cowens had clearly erred in issuing the protective order.