Updated from 2:50 p.m. EDT

Biotech and other health care stocks edged lower Wednesday on a precipitous drop from Dendreon ( DNDN) and a host of poor earnings.

Dendreon, the biopharmaceutical company that saw shares soar to more than $25 early last month, experienced a dramatic fall after the company announced that the Food and Drug Administration had asked for additional clinical data on its therapeutic cancer treatment Provenge before granting approval. Shares plummeted $11.41, or 64.3%, to $6.33.

Greater-than-expected losses sank Inspire Pharmaceuticals ( ISPH). The company reported a net first-quarter loss of $26.1 million, or 62 cents a share. Analysts polled by Thomson Financial had expected a net loss of 55 cents a share. Quarter over quarter, losses increased from $14.0 million, or 33 cents a share, from last year. Shares fell 72 cents, or 9.9%, to $6.52.

Progenics Pharmaceuticals ( PGNX) also reported a wider-than-expected first-quarter loss of $10.4 million, or 40 cents a share. In the year-ago quarter, the company reported a loss of $2.6 million, or 10 cents a share. The Thomson Financial consensus target was a loss of 14 cents a share. Progenics says its increase in expenses was mostly due to a $12.6 million increase in research and development costs incurred in its collaboration with Wyeth ( WYE), preparation for clinical trials for its other products, and an increase in personnel. Progenics shares fell 79 cents, or 3.3%, to $23.14.

Osteotech ( OSTE) reported a net first-quarter loss of $600,000, or 4 cents a share, including $1.1 million in costs associated with the settlement of certain litigation and related legal fees. Excluding those fees, adjusted non-GAAP net income was $400,000, or 2 cents a share. Net income for the same period in the previous year was $500,000, or 3 cents a share. Shares declined 35 cents, or 4.6%, to $7.24.

Following the release of its earnings, shares of AVI BioPharma ( AVII) slid 8 cents, or 2.8%, to $2.80. The biopharmaceutical company reported a net loss of $9.7 million, or 18 cents a share, compared with a net loss of $9.1 million, or 18 cents a share, for the first quarter of 2006. The Thomson Financial consensus target was a loss of 13 cents a share.

Emergent BioSolutions ( EBS) saw shares drop 71 cents, or 5.5%, to $12.31, after reporting a narrowed first-quarter loss that disappointed analysts. The company reported a net loss of $2.7 million, or 10 cents a share, compared to a loss of $4.6 million, or 21 cents a share in the year-ago quarter. Analysts were expecting the company to earn 2 cents a share.

A few stocks did buck the market's trend.

Labopharm ( DDSS) narrowed its net loss for the first quarter to $6.5 million, or 11 cents a share, from $6.8 million, or 16 cents a share, in the year-ago quarter. While the loss exceeded analysts' expectations of 8 cents a share, the stock was up 13 cents earlier in the day and closed flat at $6.63.

EntreMed ( ENMD) also rose on narrower quarter-over-quarter losses. The company reported a net loss for the first quarter of $7.7 million, or 9 cents a share, compared with a net loss of $34.7 million, or 53 cents a share, for the same period last year. The clinical-stage pharmaceutical company beat the Thomson Financial consensus target of a loss of 12 cents a share. Shares rose 6 cents, or 3.5%, to $1.77.

The Nasdaq Biotechnology index, which includes Dendreon, Avi BioPharma, Inspire Pharmaceuticals, Labopharm and Progenics Pharmaceuticals, was down 5.07, or 0.6%, to 841.51.

More from Investing

How to Make a Fortune Like Microsoft Billionaire Founder Bill Gates

How to Make a Fortune Like Microsoft Billionaire Founder Bill Gates

SEC Says Bitcoin and Ether Are Not Securities -- but Prices Stay Bearish?

SEC Says Bitcoin and Ether Are Not Securities -- but Prices Stay Bearish?

GE's Exit From Dow Could Be a Blessing in Disguise, Goldman Says

GE's Exit From Dow Could Be a Blessing in Disguise, Goldman Says

Former General Electric CEO Jack Welch Has 4 Tips to Getting a Promotion

Former General Electric CEO Jack Welch Has 4 Tips to Getting a Promotion

Own Retail Stocks? This Chart Will Make You Want to Instantly Cash Out

Own Retail Stocks? This Chart Will Make You Want to Instantly Cash Out