Immunex Corporation History

Company Perspectives:

Immunex is a leading biopharmaceutical company dedicated to developing immune system science to protect human health. Applying our scientific expertise in the field of immunology, cytokine biology, vascular biology, antibody-based therapeutics and small molecule research, we work to discover new targets and new therapeutics for treating rheumatoid arthritis, or RA, asthma, and other inflammatory diseases, as well as cancer and cardiovascular diseases.

Key Dates:

1981:

Steven Gillis and Christopher Henney found Immunex in Seattle.

1987:

First clinical studies of Leukine are initiated.

1991:

Leukine is marketed for bone marrow transplant patients and receives FDA approval; ground is broken for a new pharmaceutical manufacturing facility in Bothell, Washington.

1993:

Shareholders approve merger with Lederle, a division of American Cyanamid; plans are announced for new research and development center.

1994:

American Home Products buys American Cyanamid; Edward Fritzky joins Immunex.

1996:

FDA approves Novantrone for use in hormone-refractory prostate cancer patients; scientists discover RANK, a molecule involved in the regulation of bone formation/degradation.

1997:

Immunex partners with Wyeth-Ayerst Pharmaceuticals to market Enbrel in North America.

1998:

Researchers clone TACE, a key immune system enzyme, and TRAIL, a gene critical to healthy immune systems; Enbrel receives FDA approval as first in a new class of drugs for treatment of moderate to severe rheumatoid arthritis.

1999:

Immunex stock splits two-for-one; Enbrel is approved for treatment of juvenile rheumatoid arthritis; total product sales reach $376 million and construction starts on new process development facility.

2000:

Immunex stock splits three-for-one; Novantrone is approved by FDA for treatment of worsening multiple sclerosis.

2001:

Enbrel is approved by the FDA for psoriatic arthritis and shows positive results in psoriasis trials; Immunex acquisition by Amgen is announced.

2002:

Immunex is acquired by Amgen Inc.

Company History:

Immunex Corporation is a biopharmaceutical company that develops, manufacturers, and markets therapeutic products for the treatment of cancer, infectious diseases, and autoimmune disorders. The company more than doubled its revenue base between 1992 and 1993 as a result of a merger with Lederle pharmaceutical units of American Cyanamid Company. However, in the mid-1990s, Immunex was still trying to achieve profitability after investing heavily in research and development since its inception in 1981. Immunex is best associated with the development of products such as Enbrel, used in the treatment of rheumatoid arthritis; Novantrone, used to treat acute nonlymphocytic leukemia and pain associated with prostate cancer; and Leukine, for use in bone marrow transplant patients. In July 2002, Immunex was bought by Amgen Inc., the world's largest biotechnology company.

Immunex Founded by Scientists Gillis and Henney

Immunex was formed during the start of the biotechnology craze of the early 1980s. Biotechnology, as it was known in the mid-1990s, was born in the early 1950s, when the structure of DNA was discovered; that revelation lead to the understanding of the process by which proteins are formed. Subsequent breakthroughs, particularly in the early 1970s, showed that it was possible to genetically alter microorganisms and, importantly, produce mass amounts of proteins that naturally occurred only in small quantities. A handful of companies pioneered the commercial biotechnology industry during the middle and late 1970s, but it was not until the early 1980s that a horde of competitors jumped into the game. The pivotal turning point came when the U.S. Supreme Court ruled that genetically engineered bacterium could be patented. For many, that ruling suggested the possibility of fantastic profits for biotech innovators.

Eager to make their mark in the burgeoning commercial biotechnology industry were scientists Steven Gillis and Christopher Henney. Henney, a Ph. D., was internationally recognized for his research in immunology. Gillis also had a doctorate--in biological sciences from Dartmouth College--and was recognized for his contributions related to immunology research. Gillis and Henney believed that they possessed the expertise to develop a method of producing large quantities of certain hormones that showed promise in fighting infection. At the urging of Seattle patent attorney Jim Uhlir, they formed Immunex as a means of developing and commercializing their techniques and drugs.

Joining the duo was Steve Duzan, an entrepreneur who owned an industrial ice-making machine business at the time. Duzan had become intrigued by the emerging biotechnology industry after being introduced to Gillis and Henney. Although prior to joining their startup effort, Duzan had virtually no experience in medical-related industries and did know how to raise investment capital. He was, however, known as a tenacious, hard-driving manager. At the age of 34, Duzan had arranged the leveraged buyout of the Washington-based Cello Bag Co. Inc. Then, in 1980, he engineered the sale of the company to ARCO Chemicals, Inc. He used cash from that deal to purchase North Star Ice Equipment Corp., a small manufacturer of ice-making machines that exported much of its output to the Middle East. Duzan overhauled that company's manufacturing operations and managed to improve its profitability.

Duzan was looking for another company to buy when he met Gillis and Henney. Instead, he helped them to form a completely new company called Immunex. Gillis and Henney, naturally, managed the scientific side of the business, while Duzan went to work finding capital to fund Immunex's cash-hungry research and development operations. As it turned out, many of the entrepreneurial skills that Duzan had learned in his previous business exploits were well suited to the seat-of-the-pants biotechnology sector. For the first six months, Duzan worked without a salary while he scrambled to secure investors. "Immunex was the penniless new kid on the block going up against these giants like Hoffman-LaRoche and Kodak," recalled Stephen Graham, an attorney at Immunex's law firm, in a July 21, 1991 Business Journal-Portland article. "But time and time again," he added, "when Steve looked at a transaction with those people, he would decide what a relatively little guy had a right to expect. And then he would double it. And then he would go out and get it."

While Duzan labored to find cash to fuel Immunex's product development engine, Gillis and Henney oversaw an ambitious research effort to generate various immune system stimulants and related technologies. Their goal was to develop a breakthrough drug, or drugs, that would allow Immunex to become a full-fledged pharmaceutical company that developed and manufactured its own products. But, that pivotal product proved elusive for Immunex's research team. The company's pursuits did succeed, however, in producing a number of valuable technologies and products that earned the company respect in the biotechnology industry. Specifically, Immunex discovered and cloned a long list of genes producing substances that could work in the human body to stimulate various blood cells to fight cancer, heal wounds, and prevent auto-immune diseases like arthritis and diabetes.

Immunex Introduces Leukine

Among Immunex's most important products during the mid-1980s were its Interleukin drugs and GM-CSF (Granulocyte Macrophage Colony Stimulating Factor). Those products were essentially immune system proteins that acted as hormones in the body, with each hormone commanding only specific types of cells. Each class of cells could be stimulated to respond with antibodies, enzymes, and other substances that multiplied and attacked infection. For example, Immunex's centerpiece drug, GM-CSF (marketed as Leukine), was a blood-growth stimulator that enhanced the body's production of white blood cells. Leukine could fight infection in cancer patients whose white blood cells had been destroyed during bone marrow transplants. It also had potential applications related to chemotherapy.

Although Immunex was at the technological forefront in its niche, the company faced numerous roadblocks to success. Chief among its hurdles was the Food and Drug Administration (FDA) drug approval process. To shepherd a drug through the intimidating FDA gamut, a company typically had to invest millions of dollars completing its own tests and striving to comply with Federal regulations. The obvious risk was that the drug would fail to meet FDA approval and the company would be stuck with the loss. For a smaller company like Immunex, failure could be virtually devastating. To help bring their drugs and technologies to market, therefore, many biotech startups sought other avenues to profit. Common routes included selling or licensing proprietary technology to large pharmaceutical companies, or partnering with bigger competitors to develop and market new drugs.

Immunex managed to stay solvent and continued to fund its research and development arm during the 1980s, in essence by selling its technology to companies that had the financial backing to take it to market. Some analysts criticized the strategy because it effectively turned Immunex into a "research boutique" and represented a diversion from the company's goal of becoming a true pharmaceutical company that marketed its own drugs. But, the tactic was necessary to keep the company afloat given the volatile environment of the biotechnology industry. A critical juncture for the company came in 1983, shortly after the company had gone public to raise cash through an initial public stock offering. For no apparent reason related to Immunex's performance, the company's stock price plunged from $11 to $4. The price remained suppressed while biotech investors questioned the viability of the entire industry.

Unable to generate acceptable proceeds from the sale of more stock, Duzan arranged a number of deals that benefited Immunex. He negotiated with some large American and European drug companies, selling marketing and manufacturing rights to most of the major immune-system stimulants that it had cloned. Those agreements included high-profile products like GM-CSF and its Interleukin drugs. Although forfeiting company rights to some of that technology, Duzan was credited with swinging deals that, in the long term, worked in Immunex's favor. For example, in selling marketing rights for GM-CSF to German pharmaceutical manufacturer Behringwerke AG, Duzan won a concession to oversee clinical trials for Leukine. That move later made it possible for Immunex to become a true pharmaceutical company, rather than just a research lab that collected royalties from its inventions.

Throughout the 1980s, Immunex developed a number of promising technologies, most of which it sold or licensed to other companies. As fees and royalties income increased, revenues rose steadily to about $2.4 million in 1985, $11.3 million in 1987, and $23.3 million by 1989. Profits remained elusive, however, as the company continued to pour millions into research and development. Investors had generally been patient with Immunex because the company had been so successful at developing new products. Investor patience gradually wore thin, as they watched the company spend millions without ever successfully taking a drug to market. Immunex managed to post meager profits in 1988 and 1991, but those surpluses were insignificant compared to big losses in other years. Indeed, between 1985 and 1990 Immunex lost nearly $30 million.

Despite ongoing losses, it seemed as though Immunex had turned the corner toward profitability going into the early 1990s. In a series of bold and complex deals initiated in 1989, Duzan reacquired, sold, and swapped the rights to a number of its drugs. The end result was that Immunex, by 1990, was in a position to possibly begin marketing its own technology. "In this business you've got to become a marketing organization," Duzan said in a April 15, 1990, Seattle Times article. "Because that's the only way you can get enough cash flow to sustain your research." The most significant result of Duzan's wheeling and dealing was that Immunex managed to reacquire the U.S. comarketing rights to GM-CSF and certain Interleukin drugs from its German partner Behringwerke AG. The move was risky because GM-CSF had not been approved for use in the United States by the FDA.

Immunex Receives FDA Approval for Leukine

Investors finally had something to cheer about when, in March 1991, Immunex won FDA approval to market Leukine (GM-CSF) in the United States to treat bone marrow transplant patients. The company's shares rocketed to a record high of $59 following the announcement, and Immunex initiated an aggressive marketing program to sell the product. Shortly after the approval, Immunex was selling Leukine through a 50-member sales team organized to market the product to oncology specialists. At the same time, Immunex continued to invest millions of dollars into new drugs. Chief among its research projects in the early 1990s was Pixie 321, a synthetic molecule that was designed to incorporate the properties of Leukine and Immunex's Interleukin 3 (a cancer-fighting compound). Duzan hoped to sell that and other drugs through its own sales force.

Despite notable successes during the late 1980s and early 1990s, Immunex continued to disappoint some analysts and investors. The company chalked up heavy losses, largely related to research expenses, totaling $78 million in 1992. The company had hoped to offset that deficit with increased sales of Leukine, but its marketing effort failed to live up to some analysts' hopes. The problem was partially attributable to a product similar to Leukine that was introduced by competitor Amgen. Amgen received approval for its drug, Neupogen, in 1992. Whereas Leukine had been approved for the bone marrow transplant market, Neupogen was approved for use in the much larger chemotherapy market. The result was that shipments of Neupogen bolted to $290 million in 1993, while revenues from Leukine topped out at less than $23 million. "One company operates in an ocean, the other in a pond," surmised Deborah Wardwell, a Seattle stock analyst, in the August 8, 1994, Seattle Times.

Immunex Bought Out by American Cyanamid

Encountering a fate similar to that experienced by many other biotech companies, Immunex was bought out. In June 1993, American Cyanamid purchased the company and merged it with its Lederle Oncology unit to form a new, publicly traded company still known as Immunex, and headquartered in Seattle. Lederle Oncology was a leader in the immunology industry and had about a half dozen proprietary products in its drug portfolio. Lederle, with its more established marketing network, seemed like a natural complement to Immunex's powerful research operations. The merger initially failed to produce the desired results, however, because Lederle's products did not sell as well as expected. That problem, combined with less-than-stellar gains with Leukine, created investor disappointment with Immunex. The stock price slipped to $30 before dropping to less than $15 per share in 1994.

Frustrated, American Cyanamid brought in a new chief executive to replace Duzan, who had been accused of alienating Wall Street with his brusque nature and questionable management decisions regarding Leukine. Specifically, he had been criticized for allowing Amgen to steal more than 90 percent of the market for Leukine. Gillis, who was an Immunex co-founder and heading up Immunex's research operations at the time, stepped in as a temporary president and CEO for a few months until American Cyanamid appointed Edward Fritzky to the position. (Cofounder Henney had left Immunex in 1989 to start his own consulting company.) Fritzky came to Immunex from American Cyanmid's Lederle Laboratories division where had overseen the launch of six new products in that division and, at the age of 45, was considered a seasoned veteran in the pharmaceutical industry.

American Cyanamid Bought Out by American Home Products

Interestingly, American Cyanamid was bought out by American Home Products (AHP) in mid-1994, making the latter company the majority owner of Immunex. Fritzky remained president and CEO of the company, however, and sustained his efforts to turn Immunex into a development and marketing powerhouse in its pharmaceutical niche. Unfortunately, profits continued to evade Immunex going into the mid-1990s, amidst a string of setbacks. In September 1994, for example, cofounder Steve Gillis resigned his post to pursue other research goals. More importantly, the FDA refused to approve Leukine for use in the $500 million chemotherapy market that was dominated by Amgen. The stunning news sent Immunex's stock price tumbling 20 percent to less than $13 per share by May 1995. Nevertheless, management remained optimistic, given the company's proven research capabilities, pipeline of high-potential drugs, and ongoing efforts to get FDA approval to use Leukine in chemotherapy applications.

Despite setbacks, Immunex continued to strengthen its oncology franchise operations and apply understanding of immune system science beyond cancer care and into infectious and inflammatory diseases. Studies continued on new indications for Leukine and the chemotherapeutic Novantrone, shown to benefit men with hormone refractory prostate cancer. Also in 1995, Immunex marked a milestone in the battle against rheumatoid arthritis, with a clinical study of a recombinant TNF (tumor necrosis factor) receptor that proved to neutralize TNF's ability to promote inflammation, resulting in improvement in swollen and painful joints.

Immunex Introduces Enbrel

The company's financial outlook improved in 1995 and 1996 through research efforts, the franchising of existing products, and development of a broader marketing focus. In 1996, the FDA approved a new claim for Novantrone for relieving pain in late-stage prostate cancer patients, and Leukine Liquid, a white blood cell stimulant available in a multidose vial. With revenue growth from the increased sales of these products, research continued on the TNF receptor, brand named Enbrel. Other products in the development pipeline included FLT-3 ligand, affecting transplant patients; CD40 ligand, a potential candidate for the treatment of cancer and infection; and other cancer and inflammation fighting products, including TRAIL and TACE, respectively. Wyeth-Ayerst, a division of AHP, and a leader in the anti-inflammatory market, came on board to assist with investing in and marketing Enbrel. The research agreement with AHP was restructured which allowed Immunex fewer investment concerns in discovery research, and a new senior vice president position of marketing was added. These developments enabled Immunex to "transition from a biotechnology research firm with a few pharmaceutical products into a pharmaceutical enterprise dedicated to the research and development of innovative new therapeutics." The company hoped to profit from a strong market awareness and aggressive commercialization of its products.

The year 1997 was seen as a breakthrough year for Immunex. In its race to become the first to market a successful rheumatoid arthritis therapy, Immunex continued clinical trials on Enbrel. A new indication for Novantrone was also launched for treating patients suffering from prostate cancer. Record sales of Novantrone and Leukine were reached. In the area of research, promising biological therapeutic candidates, Nuvance for asthma sufferers and Mobist, an anti-tumor therapy, were introduced. As a result of increased pressure for faster development of emerging technologies and intense competition in the pharmaceutical business, Immunex formed alliances with Digital Gene Technologies, Inc., a genomics company, and American Oncology Resources, a network of U.S. oncologists.

Enbrel Receives FDA Approval

Another breakthrough year followed in 1998, with the FDA's approval of Enbrel for treatment of moderate to severe rheumatoid arthritis in patients with inadequate response to existing therapies, thus making Enbrel the first in a new class of rheumatoid arthritis drugs. Sales of Enbrel alone reached nearly $13 million in the first weeks of marketing. Expanding the potential uses for other drugs, Immunex introduced research describing the potential for Novantrone for treating patients with progressive multiple sclerosis (MS). Leukine was being evaluated for its ability to treat patients with HIV/AIDS; and Enbrel was being studied for treatment of chronic heart failure. Studies continued on Nuvance, for asthma sufferers; and Mobist and CD40 ligand, for use in cancer treatment.

With product success came financial success: total product sales reached a record $170 million for the year; sales of cancer products grew to record levels as well, lead by Leukine with a 21 percent increase over the previous year. Cash reserves at year-end reached $145 million. Immunex restructured a strategic alliance with AHP, giving AHP options to select and develop certain products and returning to Immunex worldwide rights to certain cancer products. A new consumer campaign was launched, called Enliven, to assist new patients through their initial therapy on Enbrel. A new Web site was launched, www.enbrelinfolcom, providing reimbursement assistance and customer service for patients and providers. Through alliances with ArQule, Genetics Institute, Digital Gene Technologies, and Medarex, Immunex enhanced their product growth and development capabilities.

Enbrel continued to spell success in 1999, with $367 million in U.S. sales. Two stock splits were declared in 1999: two-for-one splits in March and August. Having previously been accepted in the adult rheumatoid arthritis market, Enbrel became the first FDA-approved therapy for juvenile rheumatoid arthritis as well. Additional research was conducted in expanding the uses of Enbrel for the treatment of psoriatic arthritis and chronic heart failure. In oncology treatments, studies continued on Leukine, Mobista, and CD40 ligand, brand-named Avrend. An alliance was announced with Genentech, Inc., to jointly develop TRAIL, found to suppress and reverse tumor growth.

Construction began on a new 50,000-square-foot process development facility located in Bothell, Washington. In partnership with Wyeth-Ayerst, renovations began on a commercial-scale biologics manufacturing plant in Rhode Island; and plans were underway for a new research and technology center in Seattle, called the Helix Project, to house a world-class collaborative team in the field of immune system science.

Marketed products in 2000 included two major therapeutic classes: anti-inflammatory (Enbrel) and specialty therapeutics (Leukine, Novantrone, Thioplex, Amicar, Methotrexate sodium injectable, and Leucovorin calcium). Revenues from sales of Enbrel reached $652.4 million, approximately 76 percent of the company's total revenue for the year. In anticipation of increasing demands for Enbrel, a program was initiated to help insure uninterrupted therapy for U.S. patients. The Enbrel enrollment program called for patients who were prescribed Enbrel before January 1, 2001, to register with Immunex and receive an enrollment number, thus insuring their continued supply of the drug.

As of 2001, Leukine had received FDA approval for use in bone marrow transplant therapies for the treatment of leukemia, lymphoma and Hodgkin's disease and for use in peripheral blood progenitor cell mobilization and post-transplantation support. Novantrone was approved for treatment of certain cancers, including acute nonlymphocytic leukemia; for treating patients with pain associated with hormone refractory prostate cancer; and for treatment in MS.

In the areas of research and development, Immunex continued to focus not only on producing new biological therapeutic candidates, but building pharmaceutical franchises and expanding the commercial usefulness and revenue-producing ability of key products. These included new indications of Enbrel to include therapies for congestive heart failure, psoriatic arthritis, and psoriasis. Leukine was investigated for treatment of malignant melanoma, mucositis, anti-tumor adjuvancy, and HIV/AIDS. Clinical trials continued on Nuvance in asthma therapy; Mobista as an anti-tumor agent; and Avrend in cancer treatment.

The marketing relationship continued with AHP, with Immunex owning the rights to Enbrel in the United States and Canada, and AHP owning the rights to Enbrel in all other countries. As a result, Immunex did not receive royalties or shares of gross profits from sales of Enbrel outside the United States and Canada. Leukine was available to patients only in the United States and marketed through a specialty sales force within Immunex. In June 2000, Immuntex entered into a five-year comprehensive genomics agreement with Celera Genomics. The following month, Immunex entered into a joint development and commercialization agreement for ABX-EGF, a fully human antibody created by Abgenix, Inc., for treatment of tumors, including lung, prostate, pancreatic, colorectal, renal cell, and esophageal. In December, a five-year agreement was reached with Cambridge Antibody Technology (CAT) for the use of CAT's proprietary antibody phage display library for the discovery, development and potential commercialization of human monoclonal antibodies. Other research and development arrangements continued with Genentec and Digital Gene Technologies.

Immunex Sets Records for Sales, Profit and Cash Flow

The business of biotechnology continued to be lucrative for Immunex in 2000. Records for product sales, profit and cash flow were broken from the previous year, and a new record in the financial world was set with the largest healthcare secondary stock offering ever. On March 20, 2000, Immunex effected a three-for-one stock split.

Product sales for 2001 reached $960 million, a 16-percent increase over the previous year's sales. New records were set for sales of Enbrel, with plans to expand manufacturing capacity to keep up with growing demand. For the first time, sales of Leukine exceeded $100 million. In its first full year of sales, Novantrone increased 19 percent from the previous year. Immunex was added to the S&P 500, and Fortune magazine recognized the company as the eighth "Fastest Growing Company in America" and one of the "100 Best Companies to Work for in America."

In expanding technologies, Enbrel received FDA approval for psoriatic arthritis and trials continued for the treatment of psoriasis; ankylosing spondylitis, an inflammatory disease of the spine; and Wegener's granulomatosis, an inflammatory disease of blood vessels. Biotechnology manufacturing capabilities were expanded through the acquisition of the Rhode Island manufacturing plant from AHP, with FDA approval expected in 2002.

Three new product candidates entered "transition" status, the stage in which clinical development commences within 12 to 18 months: RANK, a bone resorption inhibitor for use in cancer and osteoporosis treatment; TEK, an anti-angiogenesis factor for use in cancer treatment, and Anti-IL-4R, an antibody for asthma therapy. Two new products in clinical development included IL-1 for treatment of inflammatory disease and ABX-EGF, codeveloped with Abgenix for inhibiting the growth of cancerous tumors.

Immunex Announces Plans to Merge with Amgen

On December 17, 2001, Immunex announced an agreement and plan to merge with Amgen Inc. and AMS Acquisition, Inc., a wholly owned subsidiary of Amgen. The total Immunex price tag would be $16 billion. Under terms of the agreement, AMS Acquistion Inc. would be merged with and into Immunex, with Immunex becoming a wholly owned subsidiary of Amgen. Each share of Immunex common stock would be exchanged for a fixed ration of 0.44 shares of Amgen common stock and cash of $4.50. Amgen would also acquire AHP's 41 percent stake in Immunex for the same purchase price per share. The price would give AHP an 8 percent stake in the new company. According to Immunex Chairman Fritzky, "The proposed integration of Immunex into Amgen would unite two biotech industry pioneers, both of which have delivered on the promise of biotechnology with leading products. The product portfolio, scientific leadership, commercial expertise, and drive for results would create a strong foundation for the new Amgen in its aspiration to become the world's best human therapeutics company."

Representing a key step in accelerating Amgen's long-term growth, on July 16, 2002, the acquisition of Immunex Corporation was complete. According to Kevin Sharer, Amgen's chairman and CEO, "Amgen will now have an enhanced position as the biotechnology leader, with a wide range of important drugs, including proven blockbusters Epogen, Neupogen, and Enbrel." Amgen also acquired key Immunex personnel in the merger. Ed Fritzky, former chairman and CEO of Immunex, became a member of Amgen's board of directors, and Doug Williams, previously Immunex executive vice president and chief technology officer, will lead the Seattle research site. Peggy Phillips, Immunex executive vice president and chief operating officer was expected to serve as a special advisor to Amgen. The integration of Amgen and Immunex produced a new Amgen, the world's largest biotechnology company with an unrivaled portfolio of primo drugs and the marketing muscle to successfully commercialize its products.

Principal Competitors:AstraZeneca; Centocor; Genentech; GlaxoSmithKline; Merck; Roche; Wyeth.

Further Reading:

• "Amgen Snags Immunex in $16 Billion Deal," Chemical Market Reporter, December 2001, p. 2.
• Cushing, William G., "Immunex Founder Stephen A. Duzan Named High-Tech Entrepreneur of the Year," Business Wire, February 10, 1989.
• Dowell, Valoree, "Immunex Appoints Steven Gillis Acting Chairman and Chief Executive Officer," PR Newswire, September 17, 1993.
• ------, "Immunex Founder Resigns, Continues as Consultant," PR Newswire, September 29, 1994.
• "Drug Helps Delay Progression of Multiple Sclerosis" FDA Consumer, January-February 2001, p. 4.
• Grunbaum, Rami, "Energetic CEO's Goal: Deliver on Immunex Promise," Puget Sound Business Journal, April 22, 1994, p. 1.
• ------, "Stephen Duzan: Immunex Chairman Puts Young Company in the Big Leagues," Business Journal-Portland, July 22, 1991, p. 12.
• Gupta, Himanee, "Immunex's 1st Product Brings Profit," Seattle Times, July 26, 1991, p. C10.
• Harrison, Joan, "Amgen/Immunex Acts as a Carrot for Firms with Big Growth Aspirations," Mergers and Acquisitions, March 2002, p. 23.
• Heberlein, Greg, "Immunex Chief Rolls with the Punches," Seattle Times, August 8, 1994, p. E1.
• ------, "Merger Boosts Immunex Stock," Seattle Times, August 18, 1994, p. D1.
• Lalonde, James E., "Betting On a Blockbuster: Wall Street Now See "Transformed' Immunex," Seattle Times, April 15, 1990, p. E1.
• ------, "Immunex Founder Resigns," Seattle Times, August 2, 1989, p. G10.
• "Leukemia Drug Approved for Prostate Cancer," FDA Consumer, March 1997, pp. 2-4.
• Lim, Paul J., "Immunex Reassures Investors," Seattle Times, April 27, 1995, p. D3.
• Milburn, Karen, "Immunex Cools Expectations," Puget Sound Journal, April 24, 1989, p. 10.
• Price, Margaret, "Immunex: Tempest in a Test Tube?" Financial World, November 17, 1987, p. 18.

Source: International Directory of Company Histories, Vol. 50. St. James Press, 2003.

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