Filed by: OSI Pharmaceuticals, Inc.
      Pursuant to Rule 425 under the Securities Exchange Act of 1933, as amended

                                            Subject Company: Cell Pathways, Inc.
                                                   Commission File No.: 00024889
                                       Conference Call held on February 10, 2003

Set forth below is the portion of the transcript of a conference call held on
February 10, 2003 in which Dr. Colin Goddard, Chief Executive Officer Of OSI
Pharmaceuticals, Inc., discussed the proposed merger of OSI Pharmaceuticals,
Inc. and Cell Pathways, Inc., as announced in a press release, dated February
10, 2003.

                                 ***************

[Operator] Good morning and welcome ladies and gentlemen to the OSI
Pharmaceuticals first quarter earnings release conference call. At this time I'd
like to inform you that this conference is being recorded and that all
participants are in a listen only mode. At the request of the company we will
open up the conference for questions and answers after the presentation. I would
now like to turn the call over to Dr. Colin Goddard, Chief Executive Officer.
Please go ahead Sir.

[Dr. Goddard] Good morning and welcome to the OSI quarterly call. Most of you of
course will be aware that we issued a significant press release this morning
concerning an agreement we signed to acquire Cell Pathways. We do intend to
provide a briefing on that transaction as well as part of this call but first
I'm going to ask Bob to take us through the quarterly statement and the
principal financial information that we intended to communicate as part of the
regular call.

I will remind you before we begin that information provided in this conference
call will contain some forward looking statements including factors relating to
the Cell Pathways transaction which will include amongst others the ability of
Cell Pathways to obtain shareholder approval being something of course that is
indeterminate at the moment. Any other factors we refer to can be summarized
and viewed in detail in our SEC filings. So Bob why don't you take us through
the quarterly numbers.

[Bob Van Nostrand discusses quarterly information.]

I want to provide a little bit of information about the merger first, the way
you can find it. We will file with the Securities and Exchange Commission a
registration statement on Form S-4. The registration statement will include a
proxy statement of Cell Pathways for a meeting of its stockholders to consider
and vote upon the proposed merger. The registration statement will also serve as
a prospectus of OSI with respect to the shares of OSI to be distributed to
stockholders of Cell Pathways in the proposed transaction. OSI and Cell Pathways
will file the proxy statements/prospectuses with the SEC as soon as it is
practicable. INVESTORS AND SECURITY HOLDERS ARE URGED TO CAREFULLY READ THE
PROXY STATEMENT/PROSPECTUS REGARDING THE PROPOSED MERGER TRANSACTION, WHEN IT
BECOMES AVAILABLE, AND ANY OTHER DOCUMENTS FILED WITH THE SEC, BECAUSE THEY
WILL CONTAIN IMPORTANT INFORMATION ABOUT OSI, CELL PATHWAYS, THE MERGER AND
RELATED MATTERS.

Investors and security holders will be able to obtain a free copy of the proxy
statement (when it is available) and other documents filed by OSI at the SEC's
web site at http://www.sec.gov. In addition, you may obtain documents filed with
the SEC from OSI free of charge by requesting them in writing to the Company.






So, this morning we were delighted to announce what we believe to be an
outstanding transaction for OSI in the form of the agreement to acquire Cell
Pathways via a stock for stock merger valued at approximately $32 million. OSI
will exchange .0567 shares of OSI paid for every share of Cell Pathways upon
closing of the transaction, which is of course subject to Cell Pathways
stockholder approval which we estimate will occur by late Spring of 2003. Based
on the closing price of OSI last Friday this represents $0.80 per share front
end transaction, a 58% premium to Cell Pathways' closing price on Friday and, of
course, you will have seen from the announcement, there is an additional form of
consideration being offered by the Company in the form of a contingent value
right through which each share of Cell Pathways may be eligible for an
additional .04 shares of OSIP in the event of a successful filing of an NDA for
either of the two Cell Pathways' leading clinical candidates, Aptosyn(R) or
CP461. Lazard Freres & Co. served as the financial advisor to OSI on this
transaction.

Now as you are aware from our continuing communication over the last 2 years or
so, a key corporate development goal has been to add both oncology products and
broaden and strengthen our clinical pipeline. Also, as part of an internal
strategic planning exercise, we at the Company have identified Apoptosis as a
key field for cancer research and development. We believe that with the signing
of our agreement to acquire Cell Pathways we have continued to address these
needs and will continue to do so on an ongoing basis. Cell Pathways has been on
our "watch and wait" list for some time now. It became apparent to us at the
back end of last year that a deal may be possible. And it also emerged that this
was a competitive and fast moving process. Once we had made a diligent
determination that the core science behind the Cell Pathways platform was both
credible and exciting we set out to ensure that this undervalued company became
part of OSI.

We believe we have achieved a great deal for the shareholders of OSI, but also
for the shareholders of Cell Pathways. After the disappointment of a
"non-approvable" letter for Aptosyn(R) in the colonic polyosis indication Cell
Pathways has perhaps been widely viewed as a "fallen angel," and unfortunately
they lack the financial resources and probably the depth of clinical and
regulatory expertise to draw out the value that we believe and they believe to
be inherent in their programs

OSI has both the financial resources and the clinical and regulatory expertise
to maximize these assets. The key pipeline compounds Aptosyn(R) and CP461 plug a
pipeline gap for us and further complement and balance our clinical pipeline
behind Tarceva(TM) by adding a pro-apoptotic part portfolio to our receptor
tyrosine kinase inhibitors and next-generation cytotoxics.

In addition, the product Gelclair(TM) provides OSI with its first approved
product in the form of a quality device that we believe addresses a very
significant unmet clinical need in oncology - that of managing oral mucositis,
a common side effect of aggressive chemotherapy and radiotherapy. A discounted
cash flow analysis of our quarterly revenue projections of up to $25-30MM per
year within 5 years for Gelclair(TM) alone gets us a long way towards
justifying the front end costs of this deal. If you add the valuation or any
form of valuation for Aptosyn(R), CP461, a very comprehensive and impressive
intellectual property estate surrounding these assets and a small library of
focused phosphodiesterase diastrade inhibitors, we believe this is a strong
deal for OSI shareholders. We believe the upside of an OSI post-deal with the
combined pipelines, cash, skill sets and of course Tarceva(TM) also make it an
attractive deal for CLPA shareholders.





This was as we mentioned a competitive process and equity was the preferred
currency of the board and management of Cell Pathways who it should be stated
really believe in their technology and wanted their shareholders to participate
in the upside with a company that could maximize the potential for this to
occur. We did not lightly use our stock, which we consider is also very and
unreasonably undervalued. That we did should be taken as a measure of a high
hurdle rate that this deal had to overcome in order for us to pull the trigger
internally. We believe the deal warrants the modest 5.7% pro-forma ownership of
shares given up to Cell Pathways shareholders and the CVR was a way of providing
upside value in an additional form to the same shareholders. If we have an NDA
within a 5 year period of the CVR we will happily accept the additional modest
dilution. The exchange ratio for the deal was set at an OSIP stock price of $15
per share, therefore we will issue 2.2 million shares in the transaction
bringing our total shares outstanding to approximately 38.7 million.

We have, as we said, identified apoptosis as one of our key areas of future
investment in anti-cancer drug development. We see the elucidation of the cGMP
phosphodiesterase pro apoptotic pathway as an innovative and emerging approach
which could allow us to establish a leadership position in the development of
pro-apoptotic anti-cancer drugs. Although not broadly researched the labs
involved in this area (namely Professor Weinstein's lab at Columbia and Dr. Paul
Bunn recently elected to serve as president of ASCO out in Colorado) are quality
investigators that we believe lend significant credibility the approach
significant credibility.

The tie-in of cGMP phosphodiesterase 1, 2 & 5 inhibition to sustained protein
kainse G activation, phosphorylation of MEKK and induction of apoptosis pathway
through the N-terminal c-Jun kinase pathway has only been elucidated in the last
2 years. And our technical diligence has concluded that this is both a
credible and indeed an exciting piece of science.

We see Aptosyn(R) as a credible prototype molecule for the class. While it was
rejected in the polyposis indication it did elicit indications of biological
activity and was well tolerated. Additionally, there is credible pre-clinical
data supporting the combination of Taxotere(R) and Aptosyn(R) in orthotopic lung
models in rats. However, the drug is not very potent and there is no phase II
data so we have assigned internally a higher than normal risk to the project
than we would typically do so for a phase III program. None-the-less the trial
is a 600 patient randomized, controlled study testing Aptosyn(R) in combination
with taxotere for the treatment of advanced non-small cell lung cancer. If the
primary survival end-point is met we will be in a strong position. The timeline
for the program is running at least 6 months behind Tarceva(TM) so we do not see
any impact on our major focus on the projected Tarceva(TM) filing date either.

Moving to CP461. This is a significantly more potent molecule than Aptosyn(R) in
terms of CGMP pofphodiesterose inhibition has activity as a single agent and in
combination with chemotherapy in a pre-clinical setting. The molecule has thus
far shown itself to be well tolerated in clinical studies. And in addition we
see encouraging hints of activity, especially in inflammatory bowel disease (or
IBD) even though we do not believe the dose is yet fully optimized. Pre-
clinical activity against prostate cancer cells and the generalized anti-cancer
activity we would expect from an agent with this mechanism of action lead us to
conclude that we will add another agent with the potential to be a blockbuster
to our pipeline should the basic science prove to translate into the clinical
setting. We will continue the existing phase I continuation study and phase
IIa clinic cancer studies with a view to optimizing dose and screening for
initial hints of activity but of course not yet decide fully upon our plans for
a full-fledged phase II program.





We also find the initial indications of activity in IBD to be intriguing and
expect to continue this program. While we would probably seek a co-promote
agreement to sell into this indication we have not yet determined the best way
to develop this alongside the other cancer indications for the drug.

Beyond the science, we find Gelclair(TM) to be a compelling niche product which
addresses a significant unmet need medically in the form oral mucositis. We also
certainly do not discount the value of net revenue estimates of $25MM/yr plus to
OSI within 3-5 years on our operating statement. From a financial perspective
the prospective revenue flows can justify a significant proportion of the value
of the acquisition. However, we have not done the deal for Gelclair(TM) alone
and see it as a strong value add to an acquisition of a technology platform with
outstanding potential. We do not believe this product alone justifies our
building of a sales force, despite this being an ongoing goal for the Company.
The product was recently partnered with Celgene in the cancer setting and the
John O. Butler Company in the dental arena. Both report positive feed-back from
the field on the product. However, both deals are too recent for it to be easy
for us to assess traction in the marketplace just yet. We have responsibility to
support marketing with Celgene and look forward to getting together with the
Celgene team to discuss ways in which we might optimize performance of this
product.

We do not believe the deal will have a significant impact on our ongoing cash
burn beyond fiscal 2003 and we expect to benefit from Gelclair(TM) revenues in
later years. The deal will have a near term cash impact of approximately $25-
$30MM in fiscal 2003 as we fully assimilate these assets. However, our baseline
forward projections of spend are based upon risk adjusted models of success of
our overall pipeline and we expect these assets which we propose to acquire in
this transaction to have been largely assimilated into our overall planning by
fiscal 2004 with cash flow from Gelclair(TM) largely offsetting any continued
incremental spend. Ongoing staff hired out of the transaction will largely fit
within our existing hiring plan. In this regard we do not intend to operate an
additional site in Horsham long term. We will closely work with the Cell
Pathways management to help facilitate our ability to recruit key talent
including certain research senior execs and will provide appropriate incentives
to effect a smooth transition. It is unfortunately unlikely that we will
retain all Cell Pathways employees but details of a transition and recruiting
plan have yet to be finalized. OSI has a culture of treating employees with
fairness and respect. We expect to do so through the course of this
transaction. We have also agreed to engage the senior execs, including the CEO,
CFO and head of R&D in consulting agreements to assist in the management of the
transition but do not anticipate adding to our executive management team or to
our Board of Directors as a result of this transaction

In summary we believe we have executed a fine deal for both the shareholders of
OSIP and their counterparts at Cell Pathways. Consider that OSI's pro-forma
portfolio pipeline following closing would consist of an FDA approved product in
Gelclair(TM), two phase III candidates in Tarceva(TM) and Aptosyn(R) (one being
Tarceva with blockbuster potential), two phase II candidates in OSI-211 and
CP-461 (one CP461 although earlier also with blockbuster potential), and four
phase I programs in OSI-7904L, OSI-7836 and the two Pfizer candidates CP-547,632
and CP-724,714. We believe this is both a very strong pipeline and an
attractively balanced pipeline with three themes, two focused on next generation
therapies targeting and apoptosis and one on improved cytotoxics. It is our view
that, following the closing of this transaction we will have made another
significant step forward in our ongoing mission to build a truly first class
cancer franchise delivering what we expect to be long-term sustained value to
our shareholders. And with that rather long briefing, I'm more than happy to
open up the floor to any questions.

[Operator instructions regarding how questions may be asked. There were no
questions regarding the transaction.]

[Dr. Goddard]: This has been a call which of course we summarized our financial
position, updated investors on the progress of our Tarceva(TM) program, but also
introduced a fairly detailed brief for the acquisition agreement that we signed
and announced this morning with Cell Pathways. You will be able to get a replay
of this conference call as well as the content of the brief I gave you on our
website in about two hours time and of course we look forward to making a series
of appropriate SEC filings and proxy filings as we move the transaction forward.
We are very excited about this transaction, we think it is a very important step
in the progress of OSI Pharmaceuticals and we certainly thank you for your
attention.