Biotechnology companies were trading higher in the last session of the week, a day after

Amgen

(AMGN) - Get Amgen Inc. Report

reported earnings and hours after

Human Genome Sciences

(HGSI)

posted a loss that was a penny better than Wall Street had expected.

The

Dow Jones U.S. Biotechnology Index

was up 4.1%, to 451.97 in recent market activity. Amgen recovered from the after-hours decline of Thursday to gain $3.76, or 6.7%, to $59.65 in recent

Nasdaq

trading.

Millennium Pharmaceuticals

(MLNM)

rose 61 cents, or 1.8%, to $35.28, while

Immunex

(IMNX)

jumped 50 cents, or 3.4%, to $15.06.

Chiron

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was up $1.90, or 4.3%, to $45.92, and Human Genome climbed $1.85, or 3.3%, to $57.70.

"I would've expected Amgen to be a little bit soft today," said

Edward Jones

analyst Bob Kirby. "Maybe

investors feel the worst news is out."

Amy Arnott, an analyst at

Morningstar

, said the movement in the biotech stocks on Friday might be attributed to Human Genome's results or investors having re-examined Amgen's numbers. "I think the Amgen news was sort of a short-term glitch, and investors realized the company has an extremely positive long-term outlook," she said.

After the bell yesterday, Amgen weighed in with

quarterly earnings and an outlook that sent the company's shares down in the extended session. The company's bottom line beat the consensus estimate by a penny, and sales rose to $798 million from $698 million a year ago thanks to strong sales of drugs such as

Neupogen

and

Epogen

.

Amgen also issued some bad news by lowering its sales guidance for the year, but the company maintained its long-term top line and earnings projections. The company attributed the downwardly revised forecast for 2001 to regulatory approval delays for its new anemia drug

Aranesp

.

Human Genome Sciences came in this morning with a first-quarter loss that wasn't as bad as analysts expected. The company said it lost $13 million, or 10 cents a share, on revenue of $5.3 million for the period. Analysts polled by

Thomson Financial/First Call

were expecting Human Genome to lose 11 cents.

"In terms of the quarterly earnings, biotech was pretty strong," Arnott said. "It has always been an extremely volatile area, and I think that's going to continue. We've been pretty cautious about valuations in the biotech sector. They're still not cheap. There could be opportunities in selected names, but it's an area we think people should be cautious about. For a lot of the smaller names there still could be a lot more downside left."