EXHIBIT 99.4

OSI PHARMACEUTICALS ANNOUNCES TARCEVA GRANTED APPROVAL IN CANADA FOR THE
TREATMENT OF ADVANCED NON-SMALL CELL LUNG CANCER

      MELVILLE, N.Y.--(BUSINESS WIRE)--July 13, 2005--OSI Pharmaceuticals, Inc.
(Nasdaq:OSIP) announced today that Health Canada has approved Tarceva(R)
(erlotinib) for the treatment of patients with locally advanced or metastatic
non-small cell lung cancer (NSCLC), following failure of first or second-line
chemotherapy. Tarceva is approved in the United States and in Switzerland and
had received a positive opinion from the European Committee for Medicinal
Products for Human Use (CHMP) recommending approval of Tarceva for the treatment
of patients with advanced NSCLC. An approval decision by the European Commission
is anticipated over the next several months. Tarceva is an oral tablet indicated
for daily administration.

      "We congratulate our colleagues at Roche on this approval," stated Colin
Goddard, Ph.D., Chief Executive Officer of OSI Pharmaceuticals. "We are pleased
that Tarceva is being made available to lung cancer patients throughout the
world and that with the broad-based survival benefit demonstrated by Tarceva,
coupled with its side effect profile, patients and doctors have available a
treatment option other than traditional chemotherapy. With our partners,
Genentech and Roche, our commitment to further expand the label and use of
Tarceva includes adjuvant and first-line treatment of lung cancer in patients
with other tumor types and in combination with other targeted therapies."

      The Canadian approval indicates Tarceva as a monotherapy for the treatment
of patients with locally advanced or metastatic non-small cell lung cancer
(NSCLC) after failure of at least one prior chemotherapy regimen, and whose EGFR
expression status is positive or unknown.

      As in the U.S. and Swiss labels, no mandatory testing for EGFR is
required. The Canadian approval is based on data from a pivotal Phase III study,
Trial BR.21, which compared Tarceva to placebo for the treatment of patients
with advanced NSCLC, following failure of first or second-line chemotherapy.

      The pivotal study included 731 patients with advanced NSCLC for whom one
or more chemotherapy regimens had failed. Tarceva demonstrated a survival
benefit in essentially all subsets of patients examined including males and
females, patients of Asian and non-Asian origins, patients with adenocarcinoma
and squamous cell histology, patients with good as well as impaired performance
status and both smokers and non-smokers. Median and one-year survival of the
overall population in the BR.21 study was improved by 42.5 percent (6.7 versus
4.7 months) and 45 percent (31.2 versus 21.5 percent), respectively, and
patients were treated with Tarceva for an average of just over four months in
the study (23% of patients were on therapy for more than 6 months). Certain
subsets of patients, including never smokers and patients who had tumors
determined to be EGFR positive, were seen to have a large survival benefit in
response to treatment with Tarceva. The sub-group of patients who never smoked
had a substantial survival benefit with a hazard ratio of 0.42 (hazard ratio is
a measure of the risk of death and a hazard ratio of <1 indicates a survival
benefit). The sub-group of smokers also had a survival benefit (hazard ratio =
0.87) despite the fact that this group was also seen to have a 24 percent higher
rate of Tarceva clearance (higher clearance rates lead to lower levels of
exposure to drug).



      In the pivotal NSCLC trial, the most common adverse reactions in patients
receiving Tarceva were rash and diarrhea. Grade 3/4 rash and diarrhea occurred
in 9 and 6 percent of Tarceva-treated patients, respectively. Rash and diarrhea
each resulted in discontinuation of 1 percent of Tarceva-treated patients. Dose
reduction for rash and diarrhea was needed for 6 and 1 percent of patients,
respectively. Historically, there have been infrequent reports of serious
interstitial lung disease (ILD), including fatalities, in patients receiving
Tarceva for treatment of NSCLC or other advanced solid tumors. In the pivotal
trial in NSCLC, severe pulmonary reactions, including potential cases of ILD,
were infrequent (0.8 percent) and were equally distributed between treatment
arms. The overall incidence of ILD in Tarceva-treated patients from all NSCLC
studies was approximately 0.7 percent.

      Results from two earlier large, randomized, placebo-controlled clinical
trials in first-line advanced NSCLC patients showed no clinical benefit with
concurrent administration of Tarceva with doublet platinum-based chemotherapy
(carboplatin and paclitaxel or gemcitabine and cisplatin) and its use is not
recommended in that setting.

ABOUT NSCLC

      According to the World Health Organization, there are more than 1.2
million cases worldwide of lung and bronchial cancer each year, causing
approximately 1.1 million deaths annually. It is estimated that more than
173,000 people will be diagnosed with lung cancer in the United States in 2005.
According to the National Cancer Institute, lung cancer is the single largest
cause of cancer deaths in the United States and is responsible for nearly 30
percent of cancer deaths in this country. NSCLC is the most common form of the
disease and accounts for almost 80 percent of all lung cancers.

ABOUT TARCEVA

      Tarceva is a small molecule designed to target the human epidermal growth
factor receptor 1 (HER1) pathway, which is one of the factors critical to cell
growth in non-small cell lung cancer (NSCLC) and other solid tumors. HER1, also
known as EGFR, is a component of the HER signaling pathway, which plays a role
in the formation and growth of numerous cancers. Tarceva is designed to inhibit
the tyrosine kinase activity of the HER1 signaling pathway inside the cell,
which may block tumor cell growth. Tarceva is the only HER1/EGFR-targeted
therapy proven to significantly prolong survival in second-line NSCLC as a
single agent.

ABOUT OSI PHARMACEUTICALS

      OSI Pharmaceuticals is committed to "shaping medicines and changing lives"
by discovering, developing and commercializing high-quality and novel
pharmaceutical products that extend life or improve the quality of life for
cancer and diabetes patients worldwide. The company operates through two
business teams, (OSI) Oncology and (OSI) Prosidion. (OSI) Oncology is focused on
developing molecular targeted therapies designed to change the paradigm of
cancer care. (OSI) Prosidion is committed to the generation of novel, targeted
therapies for the treatment of type 2 diabetes and obesity. OSI's flagship
product, Tarceva(R) (erlotinib), is the first drug discovered and developed by
OSI to obtain FDA approval and the only EGFR inhibitor to have demonstrated the
ability to improve survival in both non-small cell



lung cancer and pancreatic cancer patients. OSI markets Tarceva through
partnerships with Genentech, Inc. in the U.S. and with Roche throughout the rest
of the world.

      In addition to Tarceva, (OSI) Oncology exclusively markets Novantrone(R)
(mitoxantrone concentrate for injection) for its approved oncology indications
and markets Gelclair(R) Bioadherent Oral Gel for the relief of pain associated
with oral mucositis. The research and development pipeline consists of novel
molecularly targeted anti-cancer agents focused on signal transduction pathways
involved in cell proliferation, apoptosis and angiogenesis. The most advanced of
these programs, targeting the co-inhibition of c-kit and VEGFR, has two
candidates in development.

      This news release contains forward-looking statements. These statements
are subject to known and unknown risks and uncertainties that may cause actual
future experience and results to differ materially from the statements made.
Factors that might cause such a difference include, among others, the completion
of clinical trials, the FDA review process and other governmental regulation,
OSI's and its collaborators' abilities to successfully develop and commercialize
drug candidates, competition from other pharmaceutical companies, the ability to
effectively market products, and other factors described in OSI Pharmaceuticals'
filings with the Securities and Exchange Commission.

CONTACT: OSI Pharmaceuticals, Inc.
Kathy Galante, 631-962-2000
SOURCE: OSI Pharmaceuticals, Inc.