Amendment Letter to Letter of Intent between Sigma-Tau Pharmaceuticals, Inc. and DOR BioPharma, Inc. (May 3, 2007)

Summary

Sigma-Tau Pharmaceuticals, Inc. and DOR BioPharma, Inc. have agreed to amend their previous Letter of Intent. DOR will repay Sigma-Tau $2 million in cash by May 31, 2007, with 6% annual interest starting from that date. All other terms of the original agreement remain unchanged. Both parties have signed this letter to confirm their acceptance of these revised terms.

EX-10.1 2 sigmatauletter.htm SIGMA TAU LETTER 050307 Sigma Tau Letter 050307

Exhibit 10.1

Sigma-Tau Pharmaceuticals. Inc.

800 South Frederick Ave., Suite 300

Gathersburg, MD 20877

Tel: 301 ###-###-####

Fax ###-###-####

May 3, 2007

DOR BioPharma, Inc.

1101 Brickell Avenue, Suite 701-S

Miami, FL 33131-3105

Attn: Christopher J. Schaber, Ph.D.

President and Chief Executive Officer

Dear Sirs,

RE: Letter of Intent entered into by and between Sigma-Tau Pharmaceuticals, Inc. (“STPI”) and DOR BioPharma, Inc. (“DOR”) on January 3, 2007 (the “LOI”)

Reference is made to the LOI and to our letter dated February 21, 2007 addressed to you.

This is to confirm that the Reimbursable Amount (i.e. US$2 million) received by DOR under the LOI will be paid back to STPI in cash by DOR within May 31, 2007 plus six percent (6%) interest compounded annually with accrual beginning May 31, 2007.

Section 5, first sentence of the LOI is hereby amended accordingly.

All other terms and conditions of the LOI remain unchanged.

Should you be in agreement with the above please sign a copy of this letter for acceptance and return it to us for our legal files.

Yours Truly,

/s/ Gregg Lapointe

Gregg Lapointe

Chief Operating Officer

Sigma-Tau Pharmaceuticals, Inc. /s/ Christopher J. Schaber 5/3/07

Dedicated to providing

new therapies and new hope for

patients with rare diseases