Exelixis and Iconic Therapeutics Enter into Exclusive Option and License Agreement for Novel Antibody-Drug Conjugate Program

̶ ICON-2 program targets Tissue Factor (TF) with potential broad
impact in oncology ̶

̶ Exelixis will make upfront payment and contribute research funding
for option to in-license at Investigational New Drug (IND) filing ̶

ALAMEDA, Calif. & SOUTH SAN FRANCISCO, Calif.–(BUSINESS WIRE)–Exelixis, Inc. (Nasdaq: EXEL) today announced that it has entered into
an exclusive option and license agreement with Iconic
Therapeutics, Inc. (Iconic), a private biopharmaceutical company
focused on cancer and retinal disease, to advance an innovative
next-generation antibody-drug conjugate (ADC) program for cancer. This
collaboration reflects Exelixis’ ongoing strategy to build a pipeline
beyond its lead product, CABOMETYX, through both internal drug discovery
and external business development. This agreement with Iconic is
Exelixis’ second strategic collaboration focused on novel biologics,
following the company’s collaboration with Invenra, Inc. announced in
May 2018. This exclusive agreement is Iconic’s first strategic
collaboration in oncology and leverages the company’s innovative Tissue
Factor antibody expertise.

Under the terms of the agreement, Exelixis will gain an exclusive option
to license ICON-2, Iconic’s lead oncology ADC program, in exchange for
an upfront option payment to Iconic of $7.5 million and a commitment of
preclinical development funding. Exelixis would exercise its option at
the time of a potential IND application, and upon doing so would make an
option exercise payment to Iconic and assume responsibilities for all
subsequent clinical development and commercialization activities. Should
Exelixis elect to exercise its option, Iconic will become eligible for
future development, regulatory and commercialization milestone payments,
as well as royalties on potential sales.

“Iconic Therapeutics is pursuing an innovative approach to targeting
Tissue Factor, a promising target with early clinical validation and
potential applicability across a wide variety of cancers,” said Peter
Lamb, Ph.D., Executive Vice President and Chief Scientific Officer of
Exelixis. “This agreement provides Exelixis with an attractive entry
into the antibody-drug conjugate space, and reflects our preference for
success-based terms that reward our partners for long-term shared
success. We’re looking forward to working with the Iconic team to
advance this exciting program, which is complementary to Exelixis’ small
molecule and emerging biologics capabilities.”

ICON-2 represents a potential best-in-class program targeting TF in
solid tumors. TF is highly expressed on tumor cells and in the tumor
microenvironment. TF overexpression, while not oncogenic itself,
facilitates angiogenesis, metastasis and other processes important to
tumor development and progression. ICON-2 is a rationally designed
second-generation ADC with potential for an improved therapeutic index
and safety profile.

“We believe this partnership with a premier oncology company provides
further validation of our novel approach,” said William L. Greene, M.D.,
Chief Executive Officer of Iconic Therapeutics. “Exelixis’ clinical
development and commercialization expertise, evidenced by the growing
success of the cabozantinib franchise, make it the ideal partner as we
advance this promising program towards the clinic. Iconic Therapeutics’
deep expertise in Tissue Factor biology and antibody-drug conjugate
design sets the ICON-2 program apart from other approaches to this
historically challenging target,” Dr. Greene added.

About Iconic Therapeutics

Iconic Therapeutics, Inc. is a venture-backed biopharmaceutical company
dedicated to translating an understanding of the role of Tissue Factor
biology to new therapeutics for retinal disease and cancer. The company
has developed a portfolio of proprietary molecules, which bind to and
antagonize TF expressed in disease, both in retina and in solid tumors.
Please visit www.iconictherapeutics.com
for additional information.

About Exelixis

Founded in 1994, Exelixis, Inc. (Nasdaq: EXEL) is a commercially
successful, oncology-focused biotechnology company that strives to
accelerate the discovery, development and commercialization of new
medicines for difficult-to-treat cancers. Following early work in model
genetic systems, we established a broad drug discovery and development
platform that has served as the foundation for our continued efforts to
bring new cancer therapies to patients in need. Our discovery efforts
have resulted in four commercially available products, CABOMETYX^® (cabozantinib),
COMETRIQ^® (cabozantinib), COTELLIC^® (cobimetinib)
and MINNEBRO^® (esaxerenone), and we have entered into
partnerships with leading pharmaceutical companies to bring these
important medicines to patients worldwide. Supported by revenues from
our marketed products and collaborations, we are committed to prudently
reinvesting in our business to maximize the potential of our pipeline.
We are supplementing our existing therapeutic assets with targeted
business development activities and internal drug discovery — all to
deliver the next generation of Exelixis medicines and help patients
recover stronger and live longer. Exelixis is a member of the Standard &
Poor’s (S&P) MidCap 400 index, which measures the performance of
profitable mid-sized companies. For more information about Exelixis,
please visit www.exelixis.com,
follow @ExelixisInc on
Twitter or like Exelixis,
Inc. on Facebook.

Forward-Looking Statements

This press release contains forward-looking statements, including,
without limitation, statements related to: Exelixis’ strategy to build a
pipeline beyond its lead product, CABOMETYX, through both internal drug
discovery and external business development; Exelixis’ immediate and
potential future financial and other obligations under the option and
license agreement with Iconic; the potential applicability of targeting
TF across a wide variety of cancers; the potential for ICON-2 to be
complimentary to Exelixis’ small molecule and emerging biologics
capabilities; the potential for ICON-2 to represent a best-in-class
program targeting TF and a second-generation ADC with an improved
therapeutic index and safety profile; and the potential of the
Exelixis-Iconic partnership to advance the ICON-2 program towards the
clinic. Any statements that refer to expectations, projections or other
characterizations of future events or circumstances are forward-looking
statements and are based upon Exelixis’ current plans, assumptions,
beliefs, expectations, estimates and projections. Forward-looking
statements involve risks and uncertainties. Actual results and the
timing of events could differ materially from those anticipated in the
forward-looking statements as a result of these risks and uncertainties,
which include, without limitation: the level of costs associated with
Exelixis’ commercialization, research and development, in-licensing or
acquisition of product candidates, and other activities; uncertainties
inherent in the drug discovery and product development process;
Exelixis’ dependence on its relationship with Iconic, including Iconic’s
adherence to its obligations under the option and license agreement and
the level of Iconic’s assistance to Exelixis in completing clinical
trials, pursuing regulatory approvals or successfully commercializing
partnered compounds in the territories where they may be approved; risks
and uncertainties related to regulatory review and approval processes
and Exelixis’ compliance with applicable legal and regulatory
requirements; Exelixis’ and Iconic’s ability to protect their respective
intellectual property rights; market competition; changes in economic
and business conditions; and other factors discussed under the caption
“Risk Factors” in Exelixis’ Quarterly Report on Form 10-Q filed with
the Securities and Exchange Commission (SEC) on May 1, 2019, and in
Exelixis’ future filings with the SEC. All forward-looking statements in
this press release are based on information available to Exelixis as of
the date of this press release, and Exelixis undertakes no obligation to
update or revise any forward-looking statements contained herein.

Exelixis, the Exelixis logo, CABOMETYX, COMETRIQ and COTELLIC are
registered U.S. trademarks.

MINNEBRO is a registered Japanese trademark.

Contacts

Exelixis Investors Contact:
Susan Hubbard
EVP,
Public Affairs and
Investor Relations
Exelixis,
Inc.
650-837-8194
[email protected]

Exelixis Media Contact:
Hal Mackins
415-994-0040
[email protected]

Iconic Investors/Media Contact:
Shari Annes
650-888-0902
[email protected]