UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 19, 2010

BIOVEST INTERNATIONAL, INC.

(Exact name of Registrant as Specified in its Charter)

324 South Hyde Park Avenue, Suite 350

Tampa, FL 33606

(Address of Principal Executive Offices; Zip Code)

Registrant’s telephone number, including area code: (813) 864-2554

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:

BIOVEST INTERNATIONAL, INC.

FORM 8-K

On October 19, 2010, Biovest International, Inc., a Delaware corporation (the “Company”), entered into a debtor in possession financing transaction (the “Transaction”) pursuant to which it issued an aggregate of $7.0 million in principal amount of Debtor In Possession Secured Convertible Notes (the “Notes”) and warrants to purchase shares of Company common stock (the “Warrants”) to a total of twelve accredited investors (the “Buyers”). The principal purpose of the Transaction was to satisfy the condition for confirmation of its consolidated Plan of Reorganization under Chapter 11 of Title 11, United States Code (the “Plan”) by raising additional financing prior to confirmation in order to fund initial obligations under the Plan and to support the implementation of the Plan, including to fund its operations and to provide for the advancement of its research and development efforts. On October 14, 2010, the Company’s entry into the Transaction was approved by an Interim Order of the United States Bankruptcy Court for the Middle District of Florida (Tampa Division) (the “Bankruptcy Court”), and on October 25, 2010 the Bankruptcy Court entered a final order approving the Company’s entry into the Transaction (the “Final Order”).

In connection with the Transaction, the Company and the Buyers entered into a Securities Purchase Agreement, dated October 19, 2010 (the “Purchase Agreement”), pursuant to which the Company sold and issued the Notes and Warrants to the Buyers. The following are material terms and conditions of the Notes issued pursuant to the Purchase Agreement:

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The following are material terms and conditions of the Warrants issued pursuant to the Purchase Agreement:

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The Notes are secured by a first priority security interest in the funds loaned to the Company in the Transaction and in the bank account containing such funds. The loan proceeds for the Notes and Warrants are payable by the Buyers into such secured account no later than the date of the Final Order. The Purchase Agreement provides that, on the Effective Date, the security interest with respect to such collateral will terminate.

The Purchase Agreement provides that, on the Effective Date and subject to specified conditions, (i) the Notes will be mandatorily exchanged pursuant to the terms of the Plan for new notes (the “Exchange Notes”) in the aggregate principal amount of the principal and accrued but unpaid interest then outstanding under the Exchange Notes, (ii) the Series A Warrants will be mandatorily exchanged pursuant to the terms of the Plan for new warrants to purchase a like number of shares of Company common stock (the “Series A Exchange Warrants”), and (iii) the Series B Warrants will be mandatorily exchanged pursuant to the terms of the Plan for new warrants to purchase a like number of shares of Company common stock (the “Series B Exchange Warrants”). The Exchange Notes will have substantially similar terms as the Notes, except that the Exchange Notes will be unsecured and will mature on the second (2^nd) anniversary of the Effective Date. The Series A Exchange Warrants and Series B Exchange Warrants will have substantially the same terms and conditions of the Series A Warrants and Series B Warrants, respectively.

In connection with the Transaction, the Company also agreed to issue to Roth Capital, the placement agent in the Transaction, warrants to purchase up to 467,000 shares of the Company’s common stock at an exercise price of $1.45 per share, to expire on the seventh (7^th) anniversary of the Effective Date (the “Placement Agent Warrants”). The Company’s offer and sale of the Notes, Series A Warrants, Series B Warrants, and Placement Agent Warrants (and the shares of the Company’s common stock issuable upon the conversion or exercise of the foregoing) are and will be made pursuant to the exemption provided by Rule 506 under the Securities Act of 1933, as amended. The Exchange Notes, Exchange Series A Warrants, and Exchange Series B Warrants (and the shares of the Company’s common stock issuable upon the conversion or exercise of the foregoing) will be issued pursuant to the exemption from registration provided by Section 1145 of the U.S. Bankruptcy Code, as they will be issued pursuant to the Plan as approved by the Bankruptcy Court in exchange for the Buyer’s claims under the Notes and Warrants issued to the Buyers on October 19, 2010.

The foregoing does not purport to be a complete description of the Purchase Agreement, Notes and Warrants and is qualified by reference to the full text of the Purchase Agreement, Notes and Warrants attached to this Form 8-K as Exhibits 10.1, 10.2, 10.3 and 10.4.

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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.

The following information is being furnished under Item 7.01 of Form 8-K:

The Monthly Operating Report is limited in scope, covers a limited time period and has been prepared solely for the purpose of complying with reporting requirements of the Bankruptcy Court and the Bankruptcy Code, 11 U.S.C. §§ 101-1532 (the “Bankruptcy Code”). The financial information contained in the Monthly Operating Report is preliminary and unaudited and does not purport to show the financial statements of any of the Debtors in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and, therefore, may exclude items required by GAAP, such as certain reclassifications, eliminations, accruals and disclosure items. The Company cautions readers not to place undue reliance on the Monthly Operating Report. The Monthly Operating Report may be subject to revision. The Monthly Operating Report is in a format required by the Bankruptcy Court and the Bankruptcy Code and should not be used for investment purposes. The information in the Monthly Operating Report should not be viewed as indicative of future results.

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This Current Report on Form 8-K sets forth statements that are not strictly historical in nature constitute “forward-looking statements”. Such statements include, but are not limited to, statements about BiovaxID^®, AutovaxID™, and any other statements relating to products, product candidates, product development programs, the FDA or clinical study process including the commencement, process, or completion of clinical trials, the intent to treat analysis, accelerated approval and all aspects of the regulatory process. Such statements may include, without limitation, statements with respect to the Company’s plans, objectives, expectations and intentions, and other statements identified by words such as “may,” “could,” “would,” “should,” “believes,” “expects,” “anticipates,” “estimates,” “intends,” “plans,” or similar expressions. Such forward-looking statements involve known and unknown risks, uncertainties, and other factors that may cause the actual results of Biovest to be materially different from historical results or from any results expressed or implied by such forward-looking statements. These factors include, but are not limited to, risks and uncertainties related to the progress, timing, cost, and results of clinical trials and product development programs; difficulties or delays in obtaining regulatory approval for product candidates; competition from other pharmaceutical or biotechnology companies; and the additional risks discussed in filings with the Securities and Exchange Commission. All forward-looking statements in this Form 8-K are qualified in their entirety by this cautionary statement, and Biovest undertakes no obligation to revise or update this Current Report on Form 8-K to reflect events or circumstances after the date hereof. The product names used in this statement are for identification purposes only. All trademarks and registered trademarks are the property of their respective owners.

Limitation on Incorporation by Reference

The Monthly Operating Report is being furnished for informational purposes only and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall they be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended. Registration statements or other documents filed with the U.S. Securities and Exchange Commission shall not incorporate the Monthly Operating Report or any other information set forth in this Current Report on Form 8-K by reference, except as otherwise expressly stated in such filing. This Current Report on Form 8-K will not be deemed an admission as to the materiality of any information in the report that is required to be disclosed solely by Regulation FD.

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

In reviewing the agreements included as exhibits to this report, please note that they are included to provide you with information regarding their terms and are not intended to provide any other factual or disclosure information about the Company, its affiliates or subsidiaries or other parties to the agreements. The agreements contain representations and warranties by each of the parties to the applicable agreement. These representations and warranties have been made solely for the benefit of the other parties to the applicable agreement and:

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Accordingly, these representations and warranties may not describe the actual state of affairs as of the date they were made or at any other time. Additional information about the Company may be found elsewhere in this report and the Company’s other public files, which are available without charge through the SEC’s website at http://www.sec.gov.

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Signature

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.

Date: October 25, 2010

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EXHIBIT INDEX

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