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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 arrangements 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. The Company has no intention of resuming any clinical development activities or acquiring new sources of royalty revenues. Royalty revenues from sales of PegIntron accounted for approximately 80% of the Company’s total royalty revenues for each of the years ended December 31, 2015 and 2014.

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.

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 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, 2014, 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, 2014 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 received a letter dated April 13, 2015, from counsel for Sigma Tau Pharma Ltd regarding the agreement dated November 9, 2009 (the “Agreement”) between the Company and Sigma-Tau Pharmaceuticals, Inc., Defiante Farmaceutica, S.A. and Sigma-Tau Finanzaria, S.P.A. (collectively “Sigma-Tau”). In its letter, Sigma-Tau alleged that it was entitled to offset $826,128 (the “Claim”) in rebate payments earned in the fourth quarter of 2014 and paid in the first quarter of 2015 that would otherwise have been due the Company as royalty payments under the Agreement. Sigma-Tau claimed that the offset represented the amount by which the net rebate exceeded the reserve for such payments on the balance sheet and was allowed pursuant to the indemnity provisions of the Agreement. By letter dated April 28, 2015, the Company replied that the offset was not allowed under the Agreement, and that in any event, it was time-barred. Sigma-Tau did not assert that there was any liability beyond an offset against royalties that were otherwise due.

Effective June 25, 2015, the Company and Sigma-Tau agreed to settle the Claim for $526,128. Sigma-Tau retained an amount equal to $826,128 that would, but for the Claim, be due and owing to the Company under the Agreement in the second quarter of 2015, but under the terms of the settlement agreed to pay to the Company $300,000 (the “Settlement Amount”). The Company agreed that upon receipt of such amount, it would not have a claim for $826,128 in royalties earned for the fourth quarter of 2014, provided that the Company maintains its right, upon written request to Sigma-Tau and through an independent accounting firm, to inspect the relevant records of Sigma-Tau at any time within the three-year period following the close of each calendar year for the purpose of verifying the accuracy of all payments or charges used to calculate royalties payable under the Agreement for such calendar year and to make a claim as a result of such inspection. The Company recorded the $300,000 as royalty revenue during the second quarter of 2015 and received such Settlement Amount on July 13, 2015.

In June 2015, the Company delivered notice to Nektar Therapeutics, Inc. (“Nektar”) asserting a breach of our Cross-License and Option Agreement with Nektar for Nektar’s failure to pay an immunity fee that the Company believes became payable to it under such agreement with respect to certain of the Company’s patents that would be infringed by Nektar’s products (or those of Nektar’s licensees). To date, Nektar has disputed the Company’s claim to an immunity fee. On August 14, 2015, the Company filed a summons and complaint against Nektar in the Supreme Court of New York for breach of contract (the “Complaint”). On October 23, 2015, Nektar filed a motion to dismiss the complaint. On February 2, 2016, the Supreme Court of the State of New York granted Nektar its motion to dismiss the Complaint. The Company currently intends to appeal this dismissal. While the Company continues to believe that an immunity fee is currently due and payable by Nektar and intends to continue to pursue this claim, the outcome of such dispute is uncertain and there can be no assurance that the Company will be able to collect, in full or in part, the immunity fee or any future payments related thereto from Nektar. As such, no amounts have been recorded as of December 31, 2015.

On February 4, 2016, the Company’s board of directors (the “Board”) adopted a Plan of Liquidation and Dissolution. See Note 16 Subsequent Events.