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Description of Business

Enzon Pharmaceuticals, Inc. (together with its subsidiaries, “Enzon” or the “Company”) receives royalty revenues from existing licensing arrangements with other companies primarily related to sales of four marketed drug products, namely, PegIntron ®, Sylatron ®, Macugen ® and CIMZIA ®. The Company also had previously received royalty revenues from licensing arrangement related to sales of Oncaspar and Adagen until the Company’s rights to receive royalties on sales of these products expired in 2014. In addition, the Company’s rights to receive royalties on sales of Macugen and CIMZIA expired in the U.S. and Great Britain in 2014. The primary source of the Company’s royalty revenues is sales of PegIntron, which is marketed by Merck & Co., Inc. (“Merck”). The Company currently has no clinical operations and limited corporate operations. Royalty revenues from sales of PegIntron accounted for approximately 90% and 76% of the Company’s total royalty revenues for the three months ended March 31, 2015 and 2014, respectively, and approximately 79% and 87% of the Company’s total royalty revenues for fiscal years 2014 and 2013, respectively.

The Company was previously dedicated to the research and development of innovative therapeutics for patients with high unmet medical needs. Beginning in December 2012, the Company’s Board of Directors (the “Board”), with outside consultants, began a review of the possible sale or disposition of one or more corporate assets or a sale of the Company. At that time, the Company suspended substantially all clinical development activities with a goal of conserving capital and maximizing value returned to the Company’s stockholders. By April 2013, the review did not result in a definitive offer to acquire the Company or all or substantially all of the Company’s assets. At the same time, the Company announced that its Board intended to distribute excess cash, expected to arise from ongoing royalty revenues, in the form of periodic dividends to stockholders.

Subsequently, the following significant events occurred:

In April 2013, pursuant to the terms of an asset purchase agreement, the Company sold to Belrose Pharma, Inc. (“Belrose”), all right, title and interest to the Company’s Customized PEGylation platform and related assets.

In September 2013, the Company entered into a sublease agreement, which was amended and restated in November 2013, with Axcellerate Pharma, LLC (“Axcellerate”), pursuant to which the Company subleases to Axcellerate a portion of the Company’s premises consisting of approximately 30,000 rentable square feet of the building located at 20 Kingsbridge Road, Piscataway, New Jersey and a share of related parking areas. The term of the sublease commenced on November 14, 2013 and will expire on July 30, 2021. The monthly fixed rent payable by Axcellerate to the Company under the sublease is as follows: (i) in year one, $10,417, (ii) in year two, $15,625, (iii) in year three, $20,833, (iv) in year four, $26,042 and (v) in each of years five through eight, $35,000. The sublease also provides for Axcellerate to pay additional rent to cover its applicable share of real estate taxes, operating expenses, sewer and gas usage, water usage, electricity usage and certain other charges incurred by Axcellerate.

In October 2013, the Company terminated its License and Collaboration Agreement with Santaris Pharma A/S (“Santaris”) whereby Enzon returned to Santaris the rights to molecules utilizing LNA technology including the mRNA antagonists targeting Hypoxia-Inducible Factor-1 alpha (HIF-1 alpha), the Androgen Receptor (AR), HER3, and Beta-catenin.

In March 2014, the Company entered into a novation agreement with Zhejiang Hisun Pharmaceutical Co., Ltd. ("Hisun") and Belrose (the “Novation Agreement”), pursuant to which the parties confirmed the novation of the Company’s Collaboration Agreement with Hisun to Belrose. As a consequence of the Novation Agreement , the Company received a gross amount of $550,000 from Hisun, the amount of a receivable previously written off, and paid $249,565 to Belrose. The recording of these transactions resulted in a net reduction of general and administrative expense of $300,435.

On July 16, 2014, Belrose provided written notice to Hisun asserting multiple breaches by Hisun of the Collaboration Agreement including failure to pay $450,000 of milestone payments. Belrose provided Hisun up to 60 days to cure the breaches. On September 16, Belrose notified Hisun and the Company that it was terminating the Collaboration Agreement and demanded the return of material related to PEG- SN38 and a royalty-free right to any Hisun patents related to PEG-SN38. Hisun responded on September 16 that they rejected Belrose’s assertion that Hisun had committed multiple breaches and requested that Belrose continue its performance of technology transfer under the Collaboration Agreement.

The Company wound down its remaining research and development activities during 2013 and has no intention of resuming any clinical development activities or acquiring new sources of royalty revenues.