Exhibit 10.34

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED: INFORMATION FOR WHICH CONFIDENTIAL TREATMENT HAS
BEEN REQUESTED IS OMITTED AND IS NOTED AS FOLLOWS **REDACTED**. AN
UNREDACTED VERSION OF THIS DOCUMENT HAS BEEN FILED SEPARATELY WITH THE SECURITIES AND
EXCHANGE COMMISSION.

Amendment No 3

AMENDMENT TOLICENSE AND COLLABORATION AGREEMENT

THIS AMENDMENT
TO LICENSE AND COLLABORATION AGREEMENT(this Amendment),
is entered into this 21 day  of December2007(the Effective
Date) by and betweenSantaris
Pharma A/S, a Danish corporation having
its principal place of business at Hørsholm, Denmark (Santaris),
andEnzon Pharmaceuticals,
Inc., a Delaware corporation having its
principal place of business at Bridgewater, New Jersey 08807 (Enzon).
Santaris and Enzon may be referred to  herein individually as a Party or
collectively, as the Parties.

BACKGROUND

WHEREAS,
Enzon and Santaris entered into the License and Collaboration Agreement dated
July 26, 2006 (the Agreement);
and

WHEREAS,
the Agreement was amended by Amendment No 1 dated 13thof
June and Amendment No 2 dated 25thof June 2007.

WHEREAS,
Enzon and Santaris desire to amend and restate certain provisions of the Agreement.

WHEREAS,
Enzon and Santaris changed the discovery process activities to allow Enzon to
make certain mini-tox studies.

NOW,
THEREFORE, in consideration of the covenants and obligations expressed herein
and intending to be legally bound, and otherwise bound by proper and reasonable
conduct, the Parties agree as  follows:

1.     Capitalized terms used herein and not otherwise defined shall have the meanings given to them in the Agreement.

2.     Section 5.4 of the Agreement is hereby amended and restated in its entirety as follows:

Compound Selection. Each LNA Compound delivered by Santaris to Enzon will be identified by Santaris pursuant to the selection process set forth inSchedule
5.4A(the Compound Selection Process) and shall satisfy the acceptance criteria set forth for such Additional Target inSchedule 5.4B(the Compound Acceptance Criteria). Following  the Compound Selection Process, Santaris shall provide Enzon with written
reports detailing the results of such process, including its design, synthesis, first screening efforts, second screening efforts, as well as the sequences of any and all LNA Compounds resulting from such process that meet the Compound Acceptance
Criteria. Upon

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Amendment No 3

Santaris delivery, at Santaris cost, of[**Redacted**]of each of[**Redacted**]LNA Compounds that
meet the Compound Acceptance Criteria each of which is an Accepted LNA Compound for Enzons[**Redacted**](which
LNA Compounds shall satisfy the obligations of Santaris under Section 5.3), Enzon shall pay the required amount under Section 7.3; provided, however, in the event that Santaris elects to deliver the LNA Compounds to Enzon more frequently than with
respect to[**Redacted**]Additional Target every[**Redacted**]pursuant to Section 5.3, Enzon shall not be required to pay the amount required
under Section 7.3 more than once in any[**Redacted**]period pursuant to the terms of Section 7.3. Following Enzons[**Redacted**], which shall last no longer than[**Redacted**],  Santaris shall at Santaris cost provide Enzon with one and[**Redacted**]of substance for[**Redacted**]LNA Compounds (identified by Enzon) meeting the applicable Compound Acceptance Criteria for an Additional Target (each of which is an Accepted
LNA Compound). Enzon shall have the right to synthesize or have synthesized by a Third Party, at Enzons sole cost, additional quantities of any and all LNA Compounds delivered by Santaris, as well as quantities of any additional LNA Compounds
disclosed in the written reports provided by Santaris pursuant to this Section 5.4 that also meet the applicable Compound Acceptance Criteria (each such additional LNA Compound synthesized by or for Enzon, if any shall also be an Accepted LNA
Compound).

3.     Section 5.5 of the Agreement is hereby amended and restated in its entirety as follows:

In-Vitro and In-Vivo Profiling by Enzon. Enzon shall conduct such additionalin-vitroandin-vivotesting as it deems appropriate in its sole discretion to select Accepted LNA Compounds for further Development. Enzon shall use its Diligent Efforts to determine, within[**Redacted**]after delivery of[**Redacted**]of substance for[**Redacted**]LNA
Compounds (identified by Enzon) Accepted LNA Compound against each Additional Target from Santaris, whether it wishes to select any Accepted LNA Compound to commence[**Redacted**];
provided, however, if Santaris delivers the Accepted LNA Compound for more than[**Redacted**]Additional Target in any[**Redacted**]period, Enzon shall have an additional period of time equal to the amount of time such Accepted LNA Compound was delivered earlier than expected. For example, if Santaris delivers Accepted LNA Compound against the[**Redacted**]Additional Target on[**Redacted**], Enzon shall have[**Redacted**]to
determine whether it wishes to select any Accepted LNA Compound to commence pre-clinical toxicology studies for Target[**Redacted**]and[**Redacted**]months for Target[**Redacted**]. Further, for example if Santaris delivers Accepted LNA Compound against the[**Redacted**]Additional Targets on[**Redacted**],

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Amendment No 3

Enzon shall have[**Redacted**]to determine whether it wishes to select any
Accepted LNA Compound to commence[**Redacted**]for Target[**Redacted**]and[**Redacted**]
for Target[**Redacted**]from such delivery to make such determination. Each such
Accepted LNA Compound selected by Enzon in writing to Santaris shall be designated a Selected LNA Compound.

4.     The table in Section 6.1(a) of the Agreement is hereby amended and restated in its entirety as follows:

|Development Milestone |  | Time to Achieve                                                                                                                                                                                                                                                   
|--------------------- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|                      |  |                                                                                                                                                                                                                                                                   
|[**Redacted**]        |  | [**Redacted**](or such longer period of time as extended pursuant to Section 5.5) after
delivery of one and one-half (1-1/2) grams of substance for two (2) LNA Compounds (identified by Enzon) Accepted LNA Compound against each Additional Target from Santaris
|[**Redacted**]        |  | (a)[**Redacted**]in respect of[**Redacted**];(b)[**Redacted**]after the[**Redacted**]; and(c) in respect of other Selected LNA Compounds,[**Redacted**]                                                                                                           

5.     Section 7.3 of the Agreement is hereby amended and restated in its entirety as follows:

Selected LNA Compound Acceptance Fees. Within thirty (30) days after the delivery
by Santaris of[**Redacted**]of
each of[**Redacted**]LNA Compounds that meet the Compound Acceptance Criteria for
Enzons[**Redacted**]for an Additional Target pursuant to Section 5.4, Enzon
shall pay US[**Redacted**]with respect to each of six (6) Additional Targets;provided, however, in the event that Santaris elects to
deliver the LNA Compounds meeting the Compound Acceptance Criteria for more than[**Redacted**]Additional Target in any
[**Redacted**]period, Enzon shall not be required to pay the amount required under this Section 7.3 more than once in any[**Redacted**]period. For example, if Santaris delivers

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Amendment No 3

[**Redacted**]of each of[**Redacted**]LNA Compounds that meet the Compound Acceptance Criteria for Enzons
[**Redacted**]for[**Redacted**]Additional Targets
on[**Redacted**]and delivers another[**Redacted**]of
each of[**Redacted**]LNA Compounds that meet the Compound Acceptance Criteria for Enzons
[**Redacted**]for the[**Redacted**]Additional Target
on[**Redacted**], Enzon shall owe Santaris a payment on[**Redacted**]for the[**Redacted**]Additional Target, a payment on[**Redacted**]for the[**Redacted**]Additional Target, and a payment on[**Redacted**]of the[**Redacted**]for the[**Redacted**]
Additional Target. If the first Event Milestone Payment payable under Section 7.4 in respect of any Additional Target is payable before the amount payable under this Section 7.3 in respect of such Additional Target is payable,
such amount payable under this Section 7.3 shall be paid at the same time as such Event Milestone Payment is payable. For the purpose of Section 10.4(b)(ii), the amounts payable under this Section 7.3 shall accrue upon delivery of such quantities of
LNA Compounds meeting the Compound Acceptance Criteria for an Additional Target, even if the payment may be deferred as provided above.

6.     The fourth section of Schedule 5.4. A of the Agreement is hereby amended and restated in its entirety as follows:

[**Redacted**].

7.     The last section of Schedule 5.4. A of the Agreement is hereby amended and restated in its entirety as follows:

[**Redacted**].

5.     Except as set forth in this Amendment, the Agreement shall remain in full force and effect.

6.     Resolution of all disputes arising out of or related to this Amendment or the performance, enforcement, breach or termination of this Amendment and any remedies relating thereto, shall be governed by and construed under the
substantive Laws of the State of New York, without regard to conflicts of law rules that would provide for application of the Law of a jurisdiction outside New York.  To the extent there is any such dispute, such dispute will be handled in
accordance with the procedures set forth in Section 13 of the Agreement.

7.     This Amendment may be executed in two or more counterparts (including by facsimile or pdf file) each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

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Amendment No 3

IN
WITNESS WHEREOF, the Parties have executed this Amendment in duplicate originals
by their proper officers as of the date and year first above written.

|SANTARIS PHARMA A/S            |                         | ENZON PHARMACEUTICALS, INC.     |    
|------------------------------ | ----------------------- | ------------------------------- | ---
|                               |                         |                                 |    
|                               |                         |                                 |    
|By:                            | /s/
    Keith McCullagh |                                 | By:
|                               |                         |                                 |    
|NAME: Keith McCullagh          |                         | NAME: Ivan Horak                |    
|TITLE: Chief Executive Officer |                         | TITLE: Chief Scientific Officer |    
|                               |                         |                                 |    
|                               |                         |                                 |    
|                               |                         |                                 |    
|By:                            | /s/
    Henrik Stage    |                                 | By:
|                               |                         |                                 |    
|NAME: Henrik Stage             |                         | NAME: Ralph del Campo           |    
|Chief Financial Officer        |                         | TITLE: EVP Technical Operations |    

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