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                                                                    EXHIBIT 20.1



For more information:
Investor Relations                                Press Relations
Michelle Burris                                   Jesse Ciccone
Corixa Corporation                                FitzGerald Communications Inc.
(206) 754-5720                                    (415) 986-9500
burris@corixa.com                                 jciccone@fitzcomm.com

FOR IMMEDIATE RELEASE

CORIXA CORPORATION COMPLETES ACQUISITION OF RIBI IMMUNOCHEM RESEARCH, INC.

SEATTLE, WA, OCTOBER 7, 1999 -- Corixa Corporation (Nasdaq: CRXA), a research-
and development-based biotechnology company, today announced that it has
completed the acquisition of Ribi ImmunoChem Research, Inc., a Hamilton,
Montana-based biopharmaceutical company. The acquisition combines Corixa's
antigen discovery and immunotherapeutic expertise with Ribi's adjuvant know-how
and manufacturing resources.

Corixa's combined product portfolio now includes nine programs in clinical
development, 15 preclinical or discovery programs and ten corporate partnerships
focusing on therapeutic products for cancer, infectious disease and autoimmune
disease. Moreover, the combined Corixa and Ribi portfolio ranges from products
in preclinical stage of development to products that have completed initial
pivotal Phase III clinical trials.

On June 10, 1999, Corixa announced the signing of a definitive agreement to
acquire all outstanding shares of Ribi in a stock-for-stock merger. Corixa
purchased Ribi for approximately $58.5 million, which consists of Corixa common
stock and options valued at $48 million, cash of $7.9 million paid by Corixa to
Ribi for the redemption of Ribi Series A preferred stock and transaction costs
of approximately $2.6 million. The purchase price will be allocated based on the
fair value of assets acquired and liabilities assumed and purchased goodwill.
The conversion of Ribi common stock into Corixa common stock has been calculated
using a fixed exchange ratio of 0.1685 per share of Ribi common stock
outstanding at the time of closing. All outstanding shares of Ribi Series A
Preferred Stock have been redeemed in accordance with the terms of the
acquisition agreement. The transaction is intended to qualify as a tax-free
reorganization and will be accounted for as a purchase.

Corixa plans to continue Ribi operations in Hamilton, Mont., and consolidate
most administrative functions in Seattle, Wash. As of the closing of the
acquisition, Corixa now has approximately 260 employees, including 85 employees
in Hamilton, Mont. Also at closing, Robert Ivy, chief executive officer,
president and chairman of Ribi resigned his post and became a consultant to
Corixa.



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ABOUT CORIXA

Corixa is a research- and development-based biotechnology company committed to
treating and preventing diseases by understanding and directing the immune
system. Corixa applies its expertise in immunology and its proprietary
technology platforms to the discovery and development of vaccine and other
antigen-based products. The company partners with innovative developers and
marketers of pharmaceuticals and diagnostic products to make its products
available to patients around the world. Corixa was founded in 1994 and is
headquartered in Seattle, Washington. For more information, please visit
Corixa's website at WWW.CORIXA.COM.

FORWARD-LOOKING STATEMENTS

Except for the historical information presented, certain matters discussed in
this press release are forward-looking statements that are subject to certain
risks and uncertainties that could cause actual results to differ materially
from any future results, performance or achievements expressed or implied by
such statements. Such risks and uncertainties include the failure of Ribi's
technology to complement and/or broaden Corixa's current technological platform,
the ability of the combined company to create synergies and increase the
likelihood of product approval as a result of the acquisition, possible
difficulties in combining the operating plans and scientific cultures of Corixa
and Ribi, the ability of Corixa to utilize Ribi's current manufacturing site to
produce potential Corixa products, and whether all operations will continue in
Montana. These risks are detailed from time to time in Corixa's and Ribi's
public disclosure filings with the U.S. Securities and Exchange Commission
(SEC), including Corixa's Annual Report on Form 10-K for the fiscal year ended
December 31, 1998, the Form 8-K filed on April 23, 1999, the Quarterly Report on
Form 10-Q for the quarter ended June 30, 1999, and the Corixa's Registration
Statement on Form S-4, filed on August 12, 1999. Copies of Corixa's public
disclosure filings with the Securities and Exchange Commission (SEC) are
available from its investor relations department.



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