Editor's note: This is the second in a continuing series based on the American Society of Clinical Oncology's 2005 annual meeting. Later this week, TheStreet.com will examine what the future might hold for shareholders of some of the companies that make cancer drugs. To read Part 1 of the series, please click here.

In previous years, shares of biotechnology and pharmaceutical companies could swing wildly in the days before and after the American Society of Clinical Oncology annual meeting, but what was once a near certainty may be becoming a thing of the past.

For the 2005 event, investors took a measured approach, and two factors seemed primarily responsible for the absence of significant run-ups and declines -- the lack of much truly fresh data at this year's gathering and ASCO's recent attempts to minimize the early release of trial results.

Celgene

(CELG) - Get Report

was one of the companies that drew some buying interest with its positive trial results for Revlimid and Thalomid; its shares were down 0.6% to $37 leading up to the meeting, before gaining 5.5% by the time the conference ended.

Traders and investors were buzzing about biotech following last year's ASCO meeting and after the launch of some of the first drugs for colorectal cancer,

Genentech's

(DNA)

Avastin and

ImClone's

(IMCL)

Erbitux. But for the most part, attendees waiting for breaking news heard only confirmation of results that already had been reported.

That meant the opportunities to trade on new information around ASCO, one of the biggest medical meetings of the year, might not have been as plentiful as in previous years, according to some buy-side analysts.

Looking for Angles

Taking a broad view of the sector, the American Stock Exchange Biotechnology Index ended Friday, May 6, at 526.75. One week later, the second day of ASCO, the index stood at 532.73, a gain of 1.1%, and by the time the conference ended, the measure was at 537.81.

Meanwhile, the Nasdaq Biotechnology Index went out on May 6 at 667.64. On May 17, the day ASCO wrapped up, the index was at 678.94, a 1.7% climb.

For the American Stock Exchange Pharmaceutical Index, which measures the performance of companies like

Pfizer

(PFE) - Get Report

,

Merck

(MRK) - Get Report

,

Eli Lilly

(LLY) - Get Report

TST Recommends

and

Johnson & Johnson

(JNJ) - Get Report

, the sentiment went the other way, from 333.77 at the close May 6 to 333.12 by the end of the trading session May 17.

ImClone saw its shares add more than 6% to $33.35 in the week leading up to the meeting in anticipation of several first- and second-line Erbitux trials, but by ASCO's close, the stock sat at $32.58.

A month before the ASCO meeting, Genentech shares jumped by more than 18%

after the company reported preliminary trial data showing that Avastin added to chemotherapy improved breast cancer survival compared with chemotherapy alone. Genentech co-developed Avastin with its partner

Roche

.

Genentech's shares have been creeping higher since, but the positive data on Avastin in breast and lung cancer presented at ASCO weren't especially surprising. Genentech shares rose $1.07 to $73.77 following the ASCO weekend.

Even so, Genentech was the star of the meeting. Still, the company had to contend with researchers reporting positive trial results for competitors Sorafenib and Sutent in kidney cancer. Sorafenib was developed by

Onyx Pharmaceuticals

(ONXX)

and German drug giant

Bayer

, while Sutent is from Pfizer.

Baird Research raised its price target for Genentech, reiterating an outperform rating, citing positive efficacy data on its drug Herceptin in breast cancer. The firm's Christopher Raymond says "Genentech's BioOncology franchise confirmed our expectations for meaningful commercial upside for both Herceptin and Avastin." Baird says it does or seeks to do business with the companies it covers.

Zeroing In

The aforementioned Onyx took one of the more notable hits last Monday after the busy ASCO weekend. Researchers said Sorafenib had good progression-free survival data in phase III trials involving patients with kidney cancer, but a poor partial response rate of 2%, or seven out of 335 patients who received the drug. The company reported a 4% response rate in the phase II trial, and investors expected a rate of 7% to 9% from the latest study, according to Sven Borho, founding partner of OrbiMed, one of the largest health care fund managers.

At the start of the week leading up to ASCO, Onyx shares were at $32. As the meeting began May 12, the going price was $31.85. At the end of the day on May 17, the last day of the meeting, the stock fell to $27.05.

Bear Stearns' Akhtar Samad defended the stock, upgrading Onyx shares to outperform during the meeting. The analyst says the weakness in Onyx was unjustified because "response rates for Sorafenib in

kidney cancer will likely under-predict the survival benefit which may be achieved." Bear Stearns makes a market in Onyx securities.

Strong results from trials of Pfizer's AG-013736 came out of left field, but investors didn't pay much attention to the news. Some observers said trial results looked stronger for the drug than those of the company's Sutent, but the latter is further along in development and will be pursued as a treatment for kidney cancer. AG-013736 was developed at Agouron Pharmaceuticals, now a part of Pfizer.

Pfizer shares ticked up 0.9% in the week leading up to ASCO, closing at $27.86 Friday, May 13, and getting to $28.20 the last day of the meeting, May 17.

The company "has emerged as a power oncology house with commercially viable late-stage drugs and a number of novel early stage candidates," according to a research report from David Risinger of Merrill Lynch. Risinger rates the stock neutral, saying it has modest upside potential. Merrill says the firm and its analysts own stock in the companies it covers.