A better-than-expected first-quarter earnings report couldn’t keep Chiron Corp.Shares from slipping $1.13 to $45.50 on Thursday, as profit-takers halted the brief rallyin bioscience stocks.

For the first quarter ended March 31, the Emeryville, Calif., company had a net loss of$41.1 million, or $1.41 per share, on revenues of $56.7 million. In the 1991 quarter,Chiron (NASD:CHIR) had net income of $4.7 million, or 25 cents per share, on revenues of$29 million.

The 1992 results include a $40 million non-cash charge for technology related toChiron’s purchase, with Ciba-Geigy Ltd., of the vaccine business of Scalvo SpA, plusa non-cash charge of $1.8 million for technology related to the purchase of a minorityinterest in an IntraOptics Inc. subsidiary.

“I was, overall, pleasantly surprised by the earnings simply because the companyhad been so silent about what they thought would happen, and the structure was so complexand difficult to put together independently“, said Kidder, Peabody analyst RobertKupor. “I had thought that the loss could be much larger.“

It was a good quarter,“ said Denise Bilbert of Smith Barney. “Once you takeoff the one-time charge, they were operating at break-even. I expected a loss of $10million, excluding the charge.“

Chiron received $18.4 million from its joint blood screening and diagnostics businesswith Ortho Diagnostics Systems, including $6.9 million of profit from final 1991accounting. Product sales were $23 million, compared with $10.3 million in the 1991quarter, primarily as a result of the Cetus Corp. and IntraOptics acquisitions.

R&D expenses more than doubled, to $27.9 million from $13.5 million. Expensesassociated with Cetus were $9.1 million.

Excluding the $6.9 million Ortho profit from 1991, the operating loss was about 25cents, which Kupor said was manageable. “As the quarters roll out, we should seeprofitability by the end of the year,“ he said.

Gilbert projects a 25-cent loss for the year.

The company also announced that a DHFR inhibitor being developed by Hoffmann-La Rochewill enter Phase II trials within the next 30 days in AIDS patients with Pneumocystiscarinii pneumonia. Chiron collaborated with Roche in screening for the compound,which inhibits an enzyme necessary for all organisms to replicate. Chiron would receiveroyalties on product sales.

-- Karen Berstein