On March 2, 2026 Pulmatrix ("Pulmatrix" or the "Company") (Nasdaq: PULM), a biopharmaceutical company that has focused on the development of novel inhaled therapeutic products intended to prevent and treat migraine and respiratory diseases with important unmet medical needs using its patented iSPERSE technology, reported that on February 28, 2026, Cullgen Inc. notified Pulmatrix that Cullgen was terminating the Merger Agreement (as defined herein) and related transactions thereunder. This termination follows the December 2025 announcing that Pulmatrix and Cullgen had mutually agreed to waive the "No Solicitation" clause in the Merger Agreement in order to permit each party to explore alternate transactions in the period until closing. At this time, Pulmatrix continues to pursue alternative merger opportunities.

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Peter Ludlum, Interim Chief Executive Officer of Pulmatrix, commented, "Due to the significant delays at the Chinese Regulatory Authority (CSRC) in 2025, we initiated a process earlier this year to identify an alternative reverse merger opportunity for the Company, and we are encouraged by both the interest we’ve had to date as well as the recent increase in transaction activity within our industry."

Prior Proposed Merger with Cullgen

As previously reported, on November 13, 2024, the Company entered into an agreement and plan of merger with Cullgen, as amended by Amendment No. 1 thereto on April 7, 2025 (the "Merger Agreement" and the transactions contemplated thereunder, collectively, the "Merger").

Additional information about the Merger Agreement and the previously proposed Merger was previously disclosed in a registration statement on Form S-4 (File No. 333-284993) initially filed with the Securities and Exchange Commission (the "SEC") on February 14, 2025, as amended on April 17, 2025, and May 7, 2025, and declared effective on May 9, 2025.

On June 16, 2025, the Company held a special meeting in lieu of the annual meeting of Pulmatrix stockholders, at which meeting the Company’s stockholders approved the Merger and related proposals. The closing of the Merger was subject to certain closing conditions, including approval from the China Security Regulatory Commission which had not been obtained at the time of Cullgen’s termination.

Pulmatrix Clinical Assets and Proprietary iSPERSE Technology

iSPERSE Technology

iSPERSE, also licensed to MannKind Corporation and Cipla Technologies for certain fields of use, utilizes particles that are engineered with a small, dense and dispersible profile to exceed the performance of traditional dry powder particles as the iSPERSE particles have the dispersibility advantages of porous engineered particles. Pulmatrix believes this results in superior drug delivery compared to traditional oral and injectable forms of treatment for certain diseases.

As of December 31, 2025, Pulmatrix’s patent portfolio related to iSPERSE included approximately 149 granted patents, 18 of which are U.S.-granted patents, plus approximately 48 pending patent applications in the U.S. and other jurisdictions.
PUR3100

PUR3100, a Phase 2-ready asset, is an orally inhaled dihydroergotamine ("DHE") engineered with Pulmatrix’s iSPERSE dry powder inhalation technology for the treatment of acute migraine has a Food and Drug Administration acceptance of an Investigational New Drug ("IND") application for PUR3100 and receipt of a "study may proceed" letter to proceed with a Phase 2 study. The IND includes a Phase 2 clinical protocol where safety and preliminary efficacy of PUR3100 will be investigated in patients with acute migraine.

The Phase 2 IND builds on the Phase 1 trial results of PUR3100, which were published in 2024 in the peer-reviewed publication, Headache: The Journal of Head and Face Pain. The study showed that PUR3100 achieved peak exposures in the targeted therapeutic range and time to maximum concentration occurred at five minutes after dosing at all dosing levels. The PUR3100 dose groups also showed a lower incidence of nausea and no vomiting compared to observations of nausea and vomiting in the intravenously ("IV") administered DHE dose group.
PUR1800

PUR1800 is a Narrow Spectrum Kinase Inhibitor ("NSKI"), engineered with our iSPERSE technology, for the treatment of acute exacerbations in chronic obstructive pulmonary disease ("AECOPD"). In 2023, Pulmatrix presented complete results from a Phase 1b study of PUR1800 for AECOPD, indicating PUR1800 was well-tolerated with no observed safety signals. The topline data, along with the results from chronic toxicology studies, support the continued development of PUR1800 for the treatment of AECOPD and other inflammatory respiratory diseases.

In 2024, Pulmatrix published an abstract titled "Ex vivo evaluation of the potential for Narrow Spectrum Kinase inhibitors as a treatment for Idiopathic Pulmonary Fibrosis".
PUR1900

PUR1900, approved to proceed to a Phase 3 in India conducted by our partner Cipla, is the Company’s inhaled iSPERSE formulation of the antifungal drug itraconazole being investigated for various indications. The Company and its partner, Cipla, wound down a Phase 2b trial that the Company was operating in 2024. Cipla has continued clinical development outside the United States, and in 2025 completed their Phase 2 study in India and have been approved by India’s Central Drug Standard Control Organization to proceed with a Phase 3 clinical trial.

Pulmatrix will receive 2% royalties on any potential future net sales by Cipla outside the United States should Cipla successfully market PUR1900 outside the United States. Within the United States, the Company and Cipla share the rights 50/50 and will seek to monetize PUR1900 for indications where an orally inhaled antifungal may provide a therapeutic benefit or fulfill an unmet medical need.

(Press release, Cullgen, MAR 2, 2026, View Source [SID1234663174])