<PAGE>
PROSPECTUS SUPPLEMENT Filed pursuant to Rule 424(b)(3)
(To Prospectus Dated Registration No.333-38482
August 22, 2000)
BIOSPHERE MEDICAL, INC.
2,032,255 SHARES OF COMMON STOCK
---------------
The information in this prospectus supplement concerning the Selling
Stockholders supplements the statements set forth under the caption "Selling
Stockholders" in the prospectus. Capitalized items used and not defined herein
shall have the meanings given to them in the prospectus. The information set
forth under the caption "Selling Stockholders" is supplemented as follows:
SELLING STOCKHOLDERS
We issued the shares of common stock that this prospectus covers,
including the shares of common stock underlying the warrants set forth below, in
private placements in February 2000 and July 2000. We have set forth in the
following table, to our knowledge, information about the selling stockholders as
of June 30, 2000, or such later date as the selling stockholders have provided
the information. We have calculated beneficial ownership based on SEC
requirements, and the information we have included regarding beneficial
ownership is not necessarily indicative of beneficial ownership for any other
purpose. Unless we otherwise indicate below, each stockholder named in the table
has sole voting and investment power with respect to all shares he, she or it
beneficially owns, subject to applicable community property laws. We have based
the percentage calculated for each selling stockholder is based upon the sum of
the "Common Stock" and "Common Stock Issuable Upon Exercise of Warrants"
columns.
John Carnuccio is a director and the President and Chief Executive
Officer of BioSphere; Jean-Marie Vogel is the Chairman of BioSphere; Timothy
Barberich and David Southwell, directors of BioSphere, are President and Chief
Executive Officer and Executive Vice President and Chief Financial Officer,
respectively, of Sepracor, the parent corporation of BioSphere. Sepracor is also
a selling stockholder and we are registering for Sepracor the 454,545 shares it
acquired in our private placement in July 2000. We are party to a corporate
services agreement with Sepracor whereby Sepracor provides to us, for a monthly
fee, accounting, human resources and data processing services. Sepracor is also
the guarantor of our line of credit with a bank. In connection with Sepracor's
guarantee, we are party to a security agreement with Sepracor pursuant to which
we have pledged our assets to Sepracor as collateral for its guarantee to the
bank. Except as set forth in this paragraph, none of the selling stockholders
has held any position or had any material relationship with BioSphere in the
past three years.
-1-
<PAGE>
We do not know when or in what amounts the selling stockholders may
offer shares for sale. The selling stockholders may decide not to sell all or
any of the shares that this prospectus covers. Because the selling stockholders
may offer all or some of the shares pursuant to this offering, and because there
are currently no agreements, arrangements or understandings with respect to the
sale of any of the shares that the selling stockholders will hold after
completion of the offering, we cannot estimate the number of the shares that the
selling stockholders will hold after completion of the offering. However, for
purposes of this table, we have assumed that, after completion of the offering,
the selling stockholders will hold none of the shares that this prospectus
covers.
<TABLE>
<CAPTION>
Number of
Shares of
Common
Number of Shares of Common Stock Stock to be Number of Shares of Common Stock
Beneficially Owned Prior to Offering Sold Beneficially Owned After Offering
---------------------------------------- ---------- -------------------------------------
Number Percent Number Percent
---------------------------- ------- ------------------------- -------
Common Stock Common Stock
Issuable Issuable
-------------- --------------
Name of Selling Upon Exercise Upon Exercise
Stockholders Common Stock of Warrants Common Stock of Warrants
----------------- ------------ ----------- ------------ ------------
<S> <C> <C> <C> <C> <C> <C> <C>
ABS Employees'
Venture Fund
Limited
Partnership 27,777 6,944 * 34,721 0 0 0
ACI Capital /
BSMD, LLC 16,666 4,166 * 20,832 0 0 0
ACI Capital /
BSMDI, LLC 177,777 44,444 2.1 222,221 0 0 0
Timothy J.
Barberich 75,777(1) 6,944 * 34,721 48,000(1) 0 *
Biopergs, LLC 27,777 6,944 * 34,721 0 0 0
CCL Fund LLC 18,182 0 * 18,182 0 0 0
John M.
Carnuccio 89,955(1) 1,388 * 6,943 84,400(1) 0 *
Castle Creek
Healthcare
Partners LLC 72,728 0 * 72,728 0 0 0
Cerberus
Partners, L.P. 55,556 13,889 * 69,445 0 0 0
Cerberus
International,
LTD. 116,112 27,778 1.4 138,890 5,000 0 *
Domain Public
Equity Partners
L.P. 80,000 0 * 80,000 0 0 0
</TABLE>
-2-
<PAGE>
<TABLE>
<CAPTION>
Number of
Shares of
Common
Number of Shares of Common Stock Stock to be Number of Shares of Common Stock
Beneficially Owned Prior to Offering Sold Beneficially Owned After Offering
---------------------------------------- ---------- -------------------------------------
Number Percent Number Percent
---------------------------- ------- ------------------------- -------
Common Stock Common Stock
Issuable Issuable
-------------- --------------
Name of Selling Upon Exercise Upon Exercise
Stockholders Common Stock of Warrants Common Stock of Warrants
----------------- ------------ ----------- ------------ ------------
<S> <C> <C> <C> <C> <C> <C> <C>
Douglas Bermingham
and George Wilson,
Trustees for the
benefit of Jane
Macrae 10,000 0 * 10,000 0 0 0
Pequod
Investments,
L.P. 200,000 25,000 2.1 149,800 50,200 0 *
Pequod
International,
LTD 125,000 16,667 1.3 103,435 38,232 0 *
Pharma w/Health 136,363 0 1.3 136,363 0 0 0
Richard Gallen
& Co. Pension
Trust 002 11,112 2,778 * 13,890 0 0 0
Richter
Investment Corp. 5,000 0 * 5,000 0 0 0
Rudman
Partners, L.P. 90,909 0 * 90,909 0 0 0
Sepracor Inc. 5,824,333 0 55.6 454,545 5,369,788 0 51.3
David P.
Southwell 13,555(1) 1,388 * 6,943 8,000(1) 0 *
Summer Hill
Partners L.P. 45,455 0 * 45,455 0 0 0
Teton Partners 50,000 0 * 50,000 0 0 0
United Capital
Management, Inc. 181,818 0 1.7 181,818 0 0 0
Ursus Capital,
L.P. 15,000 3,750 * 18,750 0 0 0
Jean-Marie Vogel 647,215(1) 1,388 5.8 6,943 641,660(1) 0 5.8
-------------------------
</TABLE>
*Represents beneficial ownership of less than one percent of our common stock.
(1) Includes shares of common stock underlying options which the following
persons may exercise within 60 days of June 30, 2000 in the following amounts:
Timothy J. Barberich, 48,000 shares; John Carnuccio, 74,400 shares; David
Southwell, 7,000 shares; and Jean-Marie Vogel, 607,433 shares. Excludes the
5,824,333 shares of common stock beneficially owned by Sepracor, the parent
corporation of BioSphere, as to which shares Messrs. Barberich, Carnuccio,
Southwell and Vogel disclaim beneficial ownership.
-3-
<PAGE>
The date of this Prospectus is September 8, 2000.
-4-
