NEW YORK - The curiosity of new investors and an apparent financial upswing (heralded partly by the opening squeak of an initial public offerings window) gained credit for drawing a record number of registrants to the Biotechnology Industry Organization's CEO & Investor Conference last week.

With focus sessions, roundtables and speeches Wednesday and Thursday, the event signed up more than 2,200 attendees and was marked by a mood that hasn't been felt in the industry for a few years: good cheer, which was palpable in the hallways of the stately Waldorf-Astoria Hotel.

Anxiety was evident, too. No sooner, it seemed, had biotechnology scored a triumph with the appointment of Mark McClellan as head of the FDA (in 2002) than President Bush made known his plan to transfer the charismatic, can-do McClellan to the leadership of the Centers for Medicare and Medicaid Services, a switch due to happen soon. Will the agency's wheels again grind slowly, as they did before the advent of McClellan? Wait and see.

Meanwhile, though, attendees churned into conference rooms. Notes were taken. Plenty of questions were asked and assumptions challenged during the sessions, which BIO designed as more interactive (and indication-specific) than the usual conference fare. Handshakes, back slaps and business cards were exchanged before and after meetings.

The industry is going strong. Cathy Friedman, managing director and co-head of Morgan Stanley's biotechnology investment banking, noted that more than 50 biotechnology firms now boast market caps of more than $500 million, "which is double what we had last year and quadruple what we had the year before. Of those 50, in the first half of this year, half of those guys are going to have really story-driving news, whether it's in the clinic or getting approval. We believe that's what's driving a lot of this as well. You actually have a real market here, it's not just Amgen and Genentech and a couple of other big companies [making news]."

Genentech Inc., though, hardly lacked for headlines. Friedman's remarks in a discussion regarding IPO opportunities came last Wednesday, the day before the FDA approved Genentech's Avastin (bevacizumab) for colorectal cancer. Avastin is a humanized therapeutic antibody that inhibits tumor growth by binding to vascular endothelial growth factor.

Avastin also got play in a focus session Wednesday on cancer immunotherapy, moderated by analyst Matthew Geller, managing director at CIBC World Markets. Ten years ago, Geller said, he predicted antibodies would be the next big thing. "Everyone sort of laughed and me and said I was crazy," he said.

No more. The humanized antibody concept "allows you to use a product repeatedly without an immune response so you don't get the bad allergic response and you can keep getting efficacy over time and get some of the wonderful results we've seen recently," Geller said.

Neither is immunotherapy anything to snicker at. In 2003, 650 industry-related cancer research and development projects were under way, with 425 immunotherapy compounds in the mix and 60 of them in Phase III, said Patricia Dimond, senior biotechnology analyst at Natexis Bleichroeder Inc.

The cancer market, sadly, will be huge as time passes and patients are kept alive longer. By 2009, about 8.4 million Americans will be diagnosed, yet treatment remains inadequate. "We burn, cut, boil people and poison them," Dimond said. "There were no advances in breast cancer for 20 years and in B-cell lymphoma for 25, and it really was the advent of monoclonal antibodies" combined with chemotherapy that led the march forward, she said.

She pointed to Genentech's Herceptin (trastuzumab) for breast cancer, which gets a 26 percent response rate when used alone for eligible patients, and the rate jumps to 50 percent when given with chemotherapy, as compared with 32 percent when chemo by itself is administered.

Every cancer patient mounts an immune response against the tumor, Dimond noted, and even those responses finally are not adequate to beat the disease. The Holy Grail, she said, is active immunotherapy - tumor vaccines - which kick the innate immune system into gear.

Currently marketed immunotherapies are passive, and most of them are antibodies. They have advantages such as quick action, tumor specificity and options for radiolabeling, as done with Bexxar (tositumomab) for non-Hodgkin's lymphoma from Corixa Corp. and GlaxoSmithKline plc. What's more, the antibodies might be formulated as cocktails to target multiple antigens.

They do carry drawbacks, being cleared fairly rapidly by the liver, so the time of efficacy is rather brief. Antigens on the tumor might disappear as the cancer mutates, and the antibody no longer works. There's a risk of toxicity from bolus infusions.

Vaccines have the great advantage of being long-term therapy based on immunologic memory, Dimond allowed. Also "somewhat daunting" is the variability of individual response. But a number of vaccines are in Phase III trials, including one from Genitope Corp., which said this month it will close registration at the end of March.

The company's trial with MyVax Personalized Immunotherapy in previously untreated follicular non-Hodgkin's lymphoma patients opened in November 2000 and is designed to test whether active immunotherapy for f-NHL can delay or prevent recurrence of disease in patients in remission following an initial course of chemotherapy. MyVax is manufactured using a tumor-specific marker expressed on the patient's malignant B cells. Genitope said it expects to immunize the last patient in March 2005, with the first interim analysis soon after.

Dimond presented a slide showing the "enormous level of activity" and an "enormous variety" of cancer therapeutics based on immunotherapy, from antigen-based vaccines to new interleukins, with major companies such as Genzyme Corp. and Aventis Pasteur, the vaccines business of Aventis SA, having stakes in the field.

Avastin's accomplishment might be just the start of major progress in the field, Dimond said, pointing to the success also of Rituxan (rituximab), approved for relapsed or refractory low-grade or follicular lymphoma. The drug was developed by Biogen Idec Inc. and is partnered with F. Hoffmann-La Roche Ltd. and Genentech. Sales of Rituxan jumped 28 percent to about $1.5 billion in the fourth quarter of last year.

"Immunotherapy drugs make money," she said, calling them "good medicine and good business."