Prospectus Supplement

This prospectus supplement supplements information contained in, and should be read in conjunction with, that certain Prospectus, dated November 17, 2006, of Biovest International, Inc. (the “Company”) as supplemented by Supplement No. 17 thereto dated January 28, 2007, Supplement No. 16 thereto dated January 22, 2007, Supplement No. 15 thereto dated December 31, 2007, Supplement No. 14 thereto dated December 31, 2007, Supplement No. 13 thereto dated November 2, 2007, Supplement No. 12 thereto dated October 18, 2007, Supplement No. 11 thereto dated September 11, 2007, Supplement No. 10 thereto dated August 15, 2007, Supplement No. 9 thereto dated June 29, 2007, Supplement No. 8 thereto dated June 14, 2007, Supplement No. 7 thereto dated May 15, 2007, Supplement No. 6 thereto dated April 19, 2007, Supplement No. 5 thereto dated March 28, 2007, Supplement No. 4 thereto dated February 14, 2007, Supplement No. 3 thereto dated January 19, 2007, Supplement No. 2 thereto dated December 29, 2006 and Supplement No. 1 thereto dated December 14, 2006. This prospectus supplement is not complete without, and may not be delivered or used except in connection with, the original Prospectus and Supplement Nos. 1 through 17 thereto. The Prospectus relates to the public sale, from time to time, of up to 18,000,000 shares of our common stock by the selling shareholders identified in the Prospectus.

The information attached to this prospectus supplement modifies and supersedes, in part, the information in the Prospectus, as supplemented. Any information that is modified or superseded in the Prospectus shall not be deemed to constitute a part of the Prospectus, except as modified or superseded by this prospectus supplement or Prospectus Supplement Nos. 1 through 17.

This prospectus supplement includes the attached Form 8-K as filed by us with the Securities and Exchange Commission on February 6, 2008.

We may amend or supplement the Prospectus from time to time by filing amendments or supplements as required. You should read the entire Prospectus and any amendments or supplements carefully before you make an investment decision.

The Securities and Exchange Commission and state securities regulators have not approved or disapproved these securities or determined if this Prospectus Supplement (or the original Prospectus dated November 17, 2006, as previously supplemented) is truthful or complete. Any representation to the contrary is a criminal offense.

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Effective as of January 31, 2008, Biovest International, Inc. (the “Company”) entered into amendments of its existing royalty agreements dated December 10, 2007 and October 29, 2007 on sales of the Company’s biologic products including BiovaxID™, with Valens U.S. SPV I, LLC (“Valens US”) and Valens Offshore SPV II, Corp. (“Valens Offshore”) (collectively, the “Valens Funds”) to amend and clarify the calculation of royalty payments from any sublicense to specify that in all cases the royalty amounts will be calculated as a percentage of sales to customers/patients. Copies of the amendments to the royalty agreement are attached as Exhibits 10.1 through 10.4 hereto.

On February 5, 2008, the Company and its parent corporation, Accentia Biopharmaceuticals, Inc. (“Accentia”) entered into an amendment to the existing royalty agreement dated October 31, 2006 on sales of the Company’s biologic products, including BiovaxID, to amend and clarify the calculation of royalty payments from any sublicense to specify that in all cases the royalty amounts will be calculated as a percentage of sales to customers/patients. A copy of the amendment to the royalty agreement is attached as Exhibit 10.5 hereto.

On February 5, 2008, the Company granted an option to Accentia (the “Conversion Option”) permitting Accentia,, in its discretion, to convert part or all of the principal and interest due to Accentia under the intercompany debt owed by the Company at the date of conversion into shares of the Company’s common stock at a conversion price of $1.10 per share (the “Conversion Price”) subject to adjustment in the event of for certain recapitalizations or in the event of the sale of the Company’s stock at prices below the Conversion Price. The Company granted piggyback and demand registration rights to Accentia for the shares underlying this Conversion Option. A copy of the amendment to the Conversion Option is attached as Exhibit 10.6 hereto.

Also on February 5, 2008, the Company entered into an understanding with Nixon Peabody, LLP, Biovest’s former counsel, whereby Biovest agreed to issue to Nixon Peabody and Nixon Peabody agreed to accept a total of 164,000 shares of the Company’s common stock in full payment of outstanding invoices.

Each of the notes and securities described above were issued by the Company as described above in transactions that were exempt from registration under the Securities Act of 1933, as amended (the “Securities Act”), by virtue of Section 4(2) of the Securities Act and by virtue of Rule 506 of Regulation D under the Securities Act. Such sale and issuance did not involve any public offering, was made without general solicitation or advertising, and all parties to the transactions are accredited investors with access to all relevant information necessary to evaluate the investment and represented to us that the Notes and Common Stock were being acquired for investment.

The information included in Item 1.01 of this Form 8-K is hereby incorporated by reference into this Item 2.03.

The information included in Item 1.01 of this Form 8-K is hereby incorporated by reference into this Item 3.02. David is this sufficient or is more detail required?

See the Exhibit Index set forth below for a list of exhibits included with this Form 8-K.

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunder duly authorized.


BIOVEST INTERNATIONAL, INC.

By:		/s/ Alan M. Pearce
		Alan M. Pearce
		Chief Financial Officer

Reference is made to the Royalty Agreement dated as of October 29, 2007 (as amended, modified or supplemented from time to time, the “Royalty Agreement”), by and between Biovest International, Inc. (the “Company”) and Valens U.S. SPV I, LLC (“Valens US”). Capitalized terms used herein that are not defined shall have the meaning given to them in the Royalty Agreement.

Valens US and the Company desire to amend the Royalty Agreement on the terms and conditions set forth below.

In consideration of Valens US’s agreement to continue to provide financial accommodations to the Company and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto hereby agree that:

a) Section 1.5 of the Royalty Agreement shall be amended and restated in its entirety to read as follows:

(a) any and all Upfront Amounts, as supported by such documentation as Valens US shall from time to time request;

(b) without duplication of any Upfront Amounts previously calculated and paid pursuant to subparagraph (a), any Sales Revenue, as supported by such documentation as Valens US shall from time to time request; and

(c) any and all Other Amounts, as supported by such documentation as Valens US shall from time to time request, less, to the extent applicable,:

(i) in the event Biovest has indicated in a prior writing to Valens US that Biovest will use at least 50% of such Other Amounts for the further development and/or commercialization of the Biovest Biologic Products, solely such amounts associated with such further development and/or commercialization plus any reasonable costs and expenses associated therewith; and/or

(ii) in the event Biovest has indicated in writing to Valens US that Biovest will use all or part of such Other Amounts to repay indebtedness due and payable by Biovest (A) to any or all of Valens US, Valens Offshore SPV II, Corp. and Laurus Master Fund, Ltd. or (B) following the indefeasible payment in full of all indebtedness due and payable by Biovest to each of Valens US, Valens Offshore SPV II, Corp. and Laurus Master Fund, Ltd., to any other creditor of Biovest, and Valens US has consented to such use in writing (which consent will not be unreasonably withheld), solely such amounts associated with such repayment of indebtedness.”

b) Section 1.6 of the Royalty Agreement shall be amended and restated in its entirety to read as follows:

“‘Licensee’ shall mean any Third Party granted a license by Biovest to manufacture, sell, or commercialize Biovest Biologic Products.”

c) a new Section 1.12 is added to the Royalty Agreement and shall read as follows:

“1.12 “Other Amounts” shall mean any amounts other than Upfront Amounts and Sales Revenue received by Biovest from a Licensee in connection with any Biovest Biologic Product.”

d) a new Section 1.13 is added to the Royalty Agreement and shall read as follows:

“1.13 “Sales Revenue” shall mean any and all revenue and other consideration received by a Licensee from a Third Party for the sale of Biovest Biologic Products, including but not limited to, revenue or royalties from sales by such Licensee of Biovest Biologic Products, upfront revenue, milestone revenue, royalty income, and the market value at the time of transfer of all non-monetary consideration such as barter or counter-trade in the country of disposition.”

e) a new Section 1.14 is added to the Royalty Agreement and shall read as follows:

“1.14 “Upfront Amounts” shall mean any and all advance revenue, advance royalties or other similar consideration received by Biovest from a Licensee for Biovest Biologic Products prior to the sale of such Biovest Biologic Products by the Licensee to a Third Party.”

f) Section 4.7 of the Royalty Agreement shall be amended and restated in its entirety to read as follows:

“Section 4.7 Right to Documentation. (a) Upon request, Valens US shall have the right to request reasonable documentation of Biovest’s calculations to determine Biovest’s Net Sales and/or License Revenue and to request discussion of such calculations with appropriate representatives of Biovest.

(b) Within ten (10) business days following the execution and delivery of any license agreement between any Licensee and Biovest, Biovest shall deliver to Valens US a true, complete and fully executed copy of such license agreement.

(c) Within ten (10) business days following the receipt by Biovest of any financial reporting documentation pursuant to any license agreement between Biovest and a Licensee, Biovest shall deliver to Valens US true and complete copies of such financial reporting documentation.”

Except as specifically amended herein, the Royalty Agreement shall remain in full force and effect, and is hereby ratified and confirmed. The execution, delivery and effectiveness of this letter agreement shall not operate as a waiver of any right, power or remedy of Valens US, nor constitute a waiver of any provision of the Royalty Agreement.

This letter agreement shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns and shall be governed by and construed in accordance with the laws of the State of New York.

This letter agreement may be executed by the parties hereto in one or more counterparts, each of which shall be deemed an original and all of which when taken together shall constitute one and the same agreement. Any signature delivered by a party by facsimile or electronic transmission shall be deemed to be an original signature hereto.


Valens U.S. SPV I, LLC

By:		Valens Capital Management, LLC, its investment manager

By:		/s/ Patrick Regan
Name:		Patrick Regan
Title:		Authorized Signatory

Reference is made to the Royalty Agreement dated as of October 29, 2007 (as amended, modified or supplemented from time to time, the “Royalty Agreement”), by and between Biovest International, Inc. (the “Company”) and Valens Offshore SPV II, Corp. (“Valens Offshore”). Capitalized terms used herein that are not defined shall have the meaning given to them in the Royalty Agreement.

Valens Offshore and the Company desire to amend the Royalty Agreement on the terms and conditions set forth below.

In consideration of Valens Offshore’s agreement to continue to provide financial accommodations to the Company and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the parties hereto hereby agree that:

a) Section 1.5 of the Royalty Agreement shall be amended and restated in its entirety to read as follows:

(a) any and all Upfront Amounts, as supported by such documentation as Valens Offshore shall from time to time request;

(b) without duplication of any Upfront Amounts previously calculated and paid pursuant to subparagraph (a), any Sales Revenue, as supported by such documentation as Valens Offshore shall from time to time request; and

(c) any and all Other Amounts, as supported by such documentation as Valens Offshore shall from time to time request, less, to the extent applicable,:

(i) in the event Biovest has indicated in a prior writing to Valens Offshore that Biovest will use at least 50% of such Other Amounts for the further development and/or commercialization of the Biovest Biologic Products, solely such amounts associated with such further development and/or commercialization plus any reasonable costs and expenses associated therewith; and/or

(ii) in the event Biovest has indicated in writing to Valens Offshore that Biovest will use all or part of such Other Amounts to repay indebtedness due and payable by Biovest (A) to any or all of Valens Offshore, Valens U.S. SPV I, LLC and Laurus Master Fund, Ltd. or (B) following the indefeasible payment in full of all indebtedness due and payable by Biovest to each of Valens Offshore, Valens U.S. SPV I, LLC and Laurus Master Fund, Ltd., to any other creditor of Biovest, and Valens Offshore has consented to such use in writing (which consent will not be unreasonably withheld), solely such amounts associated with such repayment of indebtedness.”

b) Section 1.6 of the Royalty Agreement shall be amended and restated in its entirety to read as follows:

“‘Licensee’ shall mean any Third Party granted a license by Biovest to manufacture, sell, or commercialize Biovest Biologic Products.”

c) a new Section 1.12 is added to the Royalty Agreement and shall read as follows:

“1.12 “Other Amounts” shall mean any amounts other than Upfront Amounts and Sales Revenue received by Biovest from a Licensee in connection with any Biovest Biologic Product.”

d) a new Section 1.13 is added to the Royalty Agreement and shall read as follows:

e) a new Section 1.14 is added to the Royalty Agreement and shall read as follows:

f) Section 4.7 of the Royalty Agreement shall be amended and restated in its entirety to read as follows:

“Section 4.7 Right to Documentation. (a) Upon request, Valens Offshore shall have the right to request reasonable documentation of Biovest’s calculations to determine Biovest’s Net Sales and/or License Revenue and to request discussion of such calculations with appropriate representatives of Biovest.

(b) Within ten (10) business days following the execution and delivery of any license agreement between any Licensee and Biovest, Biovest shall deliver to Valens Offshore a true, complete and fully executed copy of such license agreement.

(c) Within ten (10) business days following the receipt by Biovest of any financial reporting documentation pursuant to any license agreement between Biovest and a Licensee, Biovest shall deliver to Valens Offshore true and complete copies of such financial reporting documentation.”

Except as specifically amended herein, the Royalty Agreement shall remain in full force and effect, and is hereby ratified and confirmed. The execution, delivery and effectiveness of this letter agreement shall not operate as a waiver of any right, power or remedy of Valens Offshore, nor constitute a waiver of any provision of the Royalty Agreement.


VALENS OFFSHORE SPV II, CORP.

By:		Valens Capital Management, LLC, its investment manager

By:		/s/ Patrick Regan
Name:		Patrick Regan
Title:		Authorized Signatory

Reference is made to the Royalty Agreement dated as of December 10, 2007 (as amended, modified or supplemented from time to time, the “Royalty Agreement”), by and between Biovest International, Inc. (the “Company”) and Valens U.S. SPV I, LLC (“Valens US”). Capitalized terms used herein that are not defined shall have the meaning given to them in the Royalty Agreement.