Clovis Oncology, Inc. Receives License for Worldwide Development and Commercialization Rights to Pfizer's Oral and IV PARP Inhibitor PF-01367338

BOULDER, Colorado, June 2, 2011 -

- PF-01367338 is currently in Phase 1/2 development in combination with
chemotherapy in patients with solid tumors

- Phase 2 data from IV formulation demonstrate encouraging activity and
safety profile

- Clovis to assume responsibility for all development and commercial
activities worldwide

- Pfizer to invest in Clovis Oncology

Clovis Oncology, Inc. announced today an agreement with Pfizer Inc.
(NYSE: PFE) for the development and commercialization of Pfizer's oral and IV
Poly (ADP-ribose) polymerase (PARP) inhibitor, PF-01367338, currently in
Phase 1/2 development for solid tumors. PF-01367338 is a novel, orally
active, small molecule inhibitor of PARP and will be developed by Clovis as
both a monotherapy and in combination with chemotherapeutic agents for the
potential treatment of selected cancer patients.

Under the terms of the agreement, Clovis Oncology will take over
responsibility for global product development and commercialization. Pfizer
will receive an upfront license fee from Clovis, payable in equity in Clovis
Oncology, and will be eligible to receive further payments totaling up to
$255 million upon Clovis Oncology's successful attainment of development,
regulatory and sales milestones. Pfizer will also receive royalties on any
product sales. In addition, Pfizer Venture Investments, the venture capital
arm of Pfizer, will make a separate equity investment in Clovis Oncology.

"This drug is a very potent PARP inhibitor. It has already demonstrated
very encouraging activity as an IV formulation and now we know that the oral
formulation is also active. This potentially opens up many exciting
opportunities for long-term treatment for cancer patients," said Professor
Hilary Calvert, Director of Cancer Drug Discovery and Development at
University College London, UK, and a pioneer in the field of human cancer
therapy with PARP inhibitors. "We know that PARP inhibitors are active in
germline BRCA-mutant (gBRCA) tumors, and that this activity extends beyond
this group of tumors into broader patient populations in ovarian cancer and
may do so in other cancers as well. I am delighted to work with Clovis to
quickly bring this promising new therapy forward," he added.

PF-01367338 is currently in a Phase 1 clinical trial examining the
maximum tolerated dose of oral PF-01367338 that can be combined with
intravenous platinum chemotherapy in the treatment of solid tumors. This
program is supplemented by two ongoing trials, currently using the IV
formulation: a Phase 1/2 study in gBRCA breast and ovarian cancer and a Phase
2 study in the adjuvant treatment of triple negative breast cancer. Clovis
Oncology intends to replace the IV formulation with the oral formulation in
these studies.

"We are pleased to add PF-01367338 to our pipeline and appreciate
Pfizer's belief in our organization and in the development plans we have for
the drug. It has long been evident that inhibiting PARP may provide
significant benefit to patients with many tumor types. We are particularly
attracted to this compound because its profile suggests not only that it
could be used in combination with chemotherapy but could potentially be used
as monotherapy for the long term management of disease," said Patrick J.
Mahaffy, President and CEO of Clovis Oncology. "It is also evident that
patient selection is very important in the development of a PARP inhibitor,
and as we have for each of our other drugs, we will seek to partner with a
diagnostic company to aid in the selection of the right patients for this
drug. Clovis is building an organization dedicated to the development of
drugs with companion diagnostics, and we are gaining experience in managing
the complicated processes required to efficiently enable this strategy. "

"Clovis Oncology is the ideal choice to continue the development and
commercialization of PF-01367338," said Garry Nicholson, President and
General Manager, Pfizer Oncology. "With the number of molecules in Pfizer's
oncology pipeline, we have the opportunity to work together with innovative
companies and realize greater potential from our oncology portfolio. This
agreement is a perfect example of our effort to set priorities and to
collaborate in the interest of cancer patients worldwide."

About PARP

Poly (ADP-ribose) polymerase (PARP) is a nuclear enzyme involved in DNA
repair and programmed cell death. In noncancerous cells, DNA repair is
beneficial and promotes normal growth and proliferation of cells. DNA repair
enzymes such as PARP, whose activity and expression are up regulated in tumor
cells, are believed to contribute to resistance and dampen the effects of
chemotherapy. Therefore, inhibition of PARP can prevent the repair of single
strand DNA breaks, which in turn causes double strand DNA breaks and
ultimately leads to cancer cell death. Additionally, PARP inhibitors may be
particularly effective in treating tumors with impaired DNA repair function,
including those with BRCA 1 and BRCA 2 mutations. The use of PARP inhibitors
in the clinic has focused primarily on inducing cancer cell death in patients
with hereditary mutations in BRCA 1/2 and in patients with tumors
characterized by defective DNA repair, including breast, ovarian, prostate
and other tumor types.

About Clovis Oncology

Clovis Oncology, Inc. is a biopharmaceutical company focused on
acquiring, developing and commercializing innovative anti-cancer agents in
the U.S., Europe and additional international markets. Clovis intends to
target development programs at specific subsets of cancer populations, and
will simultaneously develop diagnostic tools that direct a compound in
development to the population that is most likely to benefit from its use.
The Company is currently developing CO-101, which is in a pivotal study for
the treatment of pancreatic cancer and CO-1686, an epidermal growth factor
receptor (EGFR) mutant-selective inhibitor (EMSI) which is currently in
pre-clinical development for non-small cell lung cancer (NSCLC) patients who
express the T790M mutation. The Company is headquartered in Boulder,
Colorado, and has additional offices in San Francisco and Cambridge, England.

For more information about Clovis Oncology, please visit the Company's
website at

www.clovisoncology.com

    For Further Information Contact:

    For Clovis Oncology
    Anna Sussman / Breanna Burkart
    Scout Investor Relations
    +1-303-907-5358 or +1-303-907-5162
    anna@scoutir.com or breanna@scoutir.com

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