[FORM OF NOTICE TO STOCKHOLDERS ACTING AS NOMINEES] PRO-PHARMACEUTICALS, INC.

Exhibit 4.5

[FORM OF NOTICE TO STOCKHOLDERS ACTING AS NOMINEES]

PRO-PHARMACEUTICALS, INC.

NOTICE TO STOCKHOLDERS WHO ARE ACTING AS NOMINEES

Up to [            ] Shares of Common Stock and

Series C Common Stock Purchase Warrants to purchase an additional [            ]

Shares of Common Stock Issuable Upon

Exercise of Rights to Subscribe for Such Shares at $[            ] per Share

This letter is being distributed to broker-dealers, trust companies, banks and other nominees in connection with the offering by Pro-Pharmaceuticals, Inc. (the “Company”) of subscription rights (the “Rights Offering”) to purchase (i) shares of the Company’s common stock, par value $0.001 per share (“Common Stock”), and (ii) transferable Series C Common Stock purchase warrants to purchase additional shares of the Common Stock (“Warrants”), by stockholders of record (“Record Date Stockholders”) as of 5:00 p.m., New York City time, on November [    ], 2008 (the “Record Date”).

Pursuant to the offering, the Company is issuing Rights to subscribe for up to [            ] shares of the Company’s Common Stock and [            ] Warrants, on the terms and subject to the conditions described in the Prospectus. The Rights may be exercised at any time during the subscription period, which commences on November [    ], 2008 and ends at 5:00 p.m., New York City time, on December [    ], 2008, unless extended by the Company in its sole discretion (as it may be extended, the “Expiration Date”). The Common Stock is presently traded on the NYSE Alternext US under the symbol “PRW”. Neither the Rights nor the Warrants underlying the Rights will be listed for trading on any stock exchange or market or on the OTC Bulletin Board. The Warrants, but not the Rights, may be sold, transferred or assigned. The Company expects the Rights and Warrants will be exercisable for shares of Common Stock listed on the NYSE Alternext US or the OTC Bulletin Board. In addition, the Warrants will be governed by a Warrant Agreement between the Company and Continental Stock Transfer & Trust Company.

As described in the Prospectus, Record Date Stockholders will receive one (1) Right for each share of Common Stock owned on the Record Date.

Each Right entitles the holder (the “Rights Holders”) to purchase: (i) one share of Common Stock at the subscription price of $[            ] per share and (ii) one Warrant that entitles the Rights Holder to purchase one share of Common Stock (the “Basic Subscription Right”). Each Warrant will be immediately exercisable following issuance through November [    ], 2009 to purchase one share of Common Stock at 125% of the price of the Basic Subscription Right, or $[            ] per share. If during the term of the Warrant the closing price of the Common Stock is equal to or greater than 400% of the warrant exercise price, or $[            ] per share, for at least ten consecutive trading days, the Company may call, or cancel any outstanding Warrants that are not exercised during the 15 trading day period following the date the Company gives notice to the holders of the remaining unexercised warrants.

Rights Holders who fully exercise their Basic Subscription Rights will be entitled to subscribe for additional shares and warrants that remain unsubscribed as a result of any unexercised Basic Subscription Rights (the “Over-Subscription Right” and together with the Basic Subscription Right, the “Rights”). Each Over-Subscription Right entitles the holder to subscribe for an additional amount equal to up to 400% of the shares of Common Stock and Warrants for which such holder was otherwise entitled to subscribe (calculated prior to the exercise of any rights). If sufficient remaining shares of Common Stock and Warrants are available, all over-subscription requests will be honored in full. If requests for shares of Common Stock and Warrants pursuant to the Over-Subscription Right exceed the remaining shares of Common Stock and Warrants available, the remaining shares of Common Stock and Warrants will be allocated pro-rata among Rights Holders who over-subscribe based on the number of Rights then held. Rights may only be exercised for whole numbers of shares; no fractional shares of Common Stock will be issued in the Rights Offering.

The Rights are evidenced by a subscription rights certificate (a “Subscription Certificate”) registered in your name or the name of your nominee.

We are asking persons who hold shares of the Company’s Common Stock beneficially, and who have received the Rights distributable with respect to those shares through a broker-dealer, trust company, bank or other nominee, to contact the appropriate institution or nominee and request it to effect the transactions for them.

If you exercise the Over-Subscription Right on behalf of beneficial owners of Rights, you will be required to certify to the Subscription Agent and the Company, in connection with the exercise of the Over-Subscription Right, as to the aggregate number of Rights that have been exercised pursuant to the Subscription Right, whether the Rights exercised pursuant to the Basic Subscription Right on behalf of each beneficial owner for which you are acting have been exercised in full and the number of shares of Common Stock and Warrants being subscribed for pursuant to the Over-Subscription Right by each beneficial owner of Rights on whose behalf you are acting.

Enclosed are copies of the following documents:

Rights not exercised at or prior to 5:00 p.m., New York City time, on the Expiration Date will expire.

Additional copies of the enclosed materials may be obtained from the Information Agent, MacKenzie Partners, Inc., toll-free at the following telephone number: (800)  ###-###-####.

NOTHING HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL MAKE YOU OR ANY OTHER PERSON AN AGENT OF THE COMPANY; THE DEALER-MANAGER, THE SUBSCRIPTION AGENT, THE INFORMATION AGENT OR ANY OTHER PERSON MAKING OR DEEMED TO BE MAKING OFFERS OF THE SECURITIES ISSUABLE UPON VALID EXERCISE OF THE RIGHTS, OR AUTHORIZE YOU OR ANY OTHER PERSON TO MAKE ANY STATEMENTS ON BEHALF OF ANY OF THEM WITH RESPECT TO THE OFFERING, EXCEPT FOR STATEMENTS MADE IN THE PROSPECTUS.