<SUBMISSION>
<ACCESSION-NUMBER>0000950123-04-005015
<TYPE>424B3
<PUBLIC-DOCUMENT-COUNT>1
<FILING-DATE>20040423
<FILER>
<COMPANY-DATA>
<CONFORMED-NAME>REGENERON PHARMACEUTICALS INC
<CIK>0000872589
<ASSIGNED-SIC>2834
<IRS-NUMBER>133444607
<STATE-OF-INCORPORATION>NY
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<FILING-VALUES>
<FORM-TYPE>424B3
<ACT>33
<FILE-NUMBER>333-74464
<FILM-NUMBER>04749847
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>777 OLD SAW MILL RIVER RD
<CITY>TARRYTOWN
<STATE>NY
<ZIP>10591-6707
<PHONE>9143477000
</BUSINESS-ADDRESS>
</FILER>
<DOCUMENT>
<TYPE>424B3
<SEQUENCE>1
<FILENAME>y96482e424b3.htm
<DESCRIPTION>REGENERON PHARMACEUTICALS
<TEXT>
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<TITLE>REGENERON PHARMACEUTICALS</TITLE>
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<H5 align="left" style="page-break-before:always">&nbsp;</H5><P>

<DIV style="font-family: 'Times New Roman',Times,serif">

<P align="right" style="font-size: 10pt">Filed pursuant to Rule&nbsp;No.&nbsp;424(b)(3)<br>
File Number 333-74464



<P align="center" style="font-size: 10pt"><B>PROSPECTUS SUPPLEMENT NO. 8<BR>
Regeneron Pharmaceuticals, Inc.</B>



<P align="center" style="font-size: 10pt"><B>$200,000,000<BR>
5.50% Convertible Senior Subordinated Notes due 2008<BR>
and Shares of Common Stock Issuable upon Conversion of the Notes</B>



<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;This prospectus supplement supplements the prospectus dated January&nbsp;24,
2002
of Regeneron Pharmaceuticals, Inc. relating to the sale by certain of our
securityholders (including their pledges, donees, assignees, transferees,
successors and others who later hold any of the securityholders&#146; interests) of
up to $200,000,000 principal amount at maturity of notes and the shares of
common stock issuable upon conversion of the notes. You should read this
prospectus supplement in conjunction with the prospectus, and this prospectus
supplement is qualified by reference to the prospectus, except to the extent
that the information in this prospectus supplement supersedes the information
contained in the prospectus.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The table of selling securityholders contained in the prospectus is hereby
modified to add as follows:

<DIV align="center">
<TABLE style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%">

<!-- Begin Table Head --><TR valign="bottom">
    <TD width="39%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="10%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="11%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="6%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="6%">&nbsp;</TD>
    <TD width="5%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
    <TD width="1%">&nbsp;</TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Aggregate Principal</B></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Number of Shares</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Percentage of</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>&nbsp;</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Amount at</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Percentage of</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>of Common Stock</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Shares of</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>&nbsp;</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Maturity of Notes</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Notes</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>that may</B></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Common Stock</B></TD>
</TR>
<TR style="font-size: 8pt" valign="bottom">
    <TD nowrap align="left"><B>Name</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>that may be Sold</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Outstanding</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>be Sold (1)</B><HR size="1" noshade></TD>
    <TD>&nbsp;</TD>
    <TD nowrap align="center" colspan="3"><B>Outstanding (2)</B><HR size="1" noshade></TD>
</TR>


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<TR valign="bottom">
    <TD><DIV style="margin-left:10px; text-indent:-10px">CIBC World Markets</DIV></TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="right">$1,000,000</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="right">*</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="right">33,056</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD align="right">*</TD>
    <TD>&nbsp;</TD>
</TR>


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</TABLE>
</DIV>


<P align="left" style="font-size: 10pt">* Less than one percent (1%).



<P>

<TABLE width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt">
<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="1%" nowrap align="right">(1)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Assumes conversion of all of the holder&#146;s notes at a conversion rate of
33.0565 shares of common
stock per $1,000 principal amount at maturity of the notes. This
conversion rate is subject to
adjustment, however, as described under &#147;Description of the Notes &#150;
Conversion of the Notes.&#148; As a
result, the number of shares of common stock issuable upon conversion
of the notes may increase or
decrease in the future.</TD>
</TR>

<TR>
    <TD colspan="5">&nbsp;</TD>
</TR>
<TR valign="top" style="font-size: 10pt; color: #000000; background: transparent">
    <TD width="1%" nowrap align="right">(2)</TD>
    <TD width="1%">&nbsp;</TD>
    <TD>Calculated based on Rule&nbsp;13d-3(d)(i) of the Exchange Act, using
53,197,081 shares of common stock
outstanding as of December&nbsp;31, 2003. In calculating this amount for each
holder, we treated as
outstanding the number of shares of common stock issuable upon conversion
of all that holder&#146;s notes,
but we did not assume conversion of any other holder&#146;s notes.</TD>
</TR>

</TABLE>


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Investing in the notes or shares of common stock involves risks that are
described
in the &#147;Risk Factors&#148; section beginning on page 5 of the prospectus.


<P align="left" style="font-size: 10pt">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined if
this
prospectus supplement is truthful or complete. Any representation to the
contrary
is a criminal offense.</B>


<P align="center" style="font-size: 10pt">The date of this prospectus supplement is April&nbsp;23, 2004




<P align="center" style="font-size: 10pt">
</DIV>


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