Pulmatrix and Cullgen Continue to Pursue Merger While Granting Each Other Waivers to Explore Alternatives

Rhea-AI Summary

Pulmatrix (NASDAQ: PULM) and Cullgen agreed on December 18, 2025 to mutually waive the No Solicitation clause in their November 2024 Merger Agreement to permit each party to explore alternative transactions while continuing to seek merger approval from the China Securities Regulatory Commission (CSRC). The companies previously completed an effective Form S-4 on May 9, 2025 and obtained stockholder approval on June 16, 2025, but CSRC approval remains outstanding.

Pulmatrix reported $4.8 million cash as of September 30, 2025 and expects funds to support operations into at least Q4 2026. Key assets include PUR3100 (Phase 2-ready with an FDA IND acceptance), PUR1800 (Phase 1b completed), PUR1900 (partnered with Cipla; Cipla finished Phase 2 in India and cleared Phase 3 there), and an iSPERSE patent portfolio of approximately 146 granted patents.

Positive

• Form S-4 declared effective on May 9, 2025
• Stockholder approval received on June 16, 2025
• IND accepted for PUR3100; Phase 2-ready
• Patent portfolio of ~146 granted patents

Negative

• Merger still awaits CSRC approval, delaying closing
• Total cash of $4.8 million funds operations only into Q4 2026
• Nasdaq listing approval required for shares issued in merger
• Mutual waiver to solicit alternatives reduces merger certainty

Key Figures

Cash & equivalents $4.8M Balance as of September 30, 2025

Cash runway into at least Q4 2026 Management expectation based on current spend

Granted patents approximately 146 iSPERSE-related patents as of September 30, 2025

U.S.-granted patents 18 Subset of iSPERSE patent portfolio

Pending patent applications approximately 50 iSPERSE-related filings in U.S. and other jurisdictions

PUR3100 PK timing 5 minutes Time to maximum concentration after dosing at all levels in Phase 1

PUR1900 royalty rate 2% Royalties on potential future net sales by Cipla outside the U.S.

Cullgen ownership 96.4% Expected pro‑forma ownership by pre‑Merger Cullgen holders at closing (from 10‑Q)

Market Reality Check

$2.37 Last Close

Volume Volume 5,534 vs 20‑day average 10,625 (relative volume 0.52 ahead of this announcement). low

Technical Shares at $4.05 trade below the $5.82 200‑day MA and are 61.06% under the 52‑week high.

Peers on Argus 2 Down

Sector context shows mixed moves among close peers (e.g., LPCN +15.05%, EVAX -3.78%), while separate momentum data flags two biotech names (ASBP, GOVX) moving down about 4% without news, suggesting broader but not uniform pressure.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Oct 16	Q3 results & divestment	Negative	-2.5%	Q3 2025 results with zero revenue and merger‑linked asset divestment plans.
Aug 06	Q2 results & merger	Negative	-3.1%	Q2 2025 results showing zero revenue and dependence on Cullgen merger.

Pattern Detected

The limited history shows that earnings and merger/divestment updates have previously been followed by modest negative price reactions.

Recent Company History

Over recent quarters, Pulmatrix focused on its proposed merger with Cullgen while divesting inhalation assets built on its iSPERSE™ platform. Q2 and Q3 2025 updates highlighted $0 revenue, shrinking operating costs, and cash balances of $5.8M (June 30, 2025) and $4.8M (Sept 30, 2025). Both updates reiterated that the Cullgen merger, approved by stockholders on June 16, 2025, still awaited Nasdaq and China Securities Regulatory Commission approvals. Today’s waiver of the “No Solicitation” clause fits into this ongoing, but delayed, merger process.

Market Pulse Summary

The stock moved -8.2% in the session following this news. A negative reaction despite the continued pursuit of the Cullgen merger would fit prior patterns, where Q2 and Q3 2025 updates with merger dependence and $0 revenue were followed by declines of -3.1% and -2.48%. This announcement underscores ongoing CSRC approval uncertainty and introduces the prospect of alternative transactions, which may signal execution risk around the original structure. Investors might focus on the modest cash balance of $4.8M, the limited float, and the possibility that extended timelines could pressure the company’s negotiating leverage.

Key Terms

china securities regulatory commission regulatory

"to work toward merger approval from the China Securities Regulatory Commission (the "CSRC")"

China Securities Regulatory Commission (CSRC) is the national government agency that oversees and enforces rules for China’s stock, bond and futures markets. Think of it as the market’s referee and rulemaker: it approves offerings, sets disclosure and conduct standards, and disciplines bad actors. Investors watch the CSRC because its decisions and regulations affect market access, transparency and the perceived safety of investing in Chinese securities.

form s-4 regulatory

"our Form S-4 filing was declared effective in May 2025"

A Form S-4 is a legal document that companies file with the government to announce and explain a major business move, such as a merger or acquisition. It provides detailed information to help investors understand how the deal might affect the company's value and future prospects, similar to a detailed blueprint that clarifies the impact of a significant change.

investigational new drug regulatory

"Food and Drug Administration acceptance of an Investigational New Drug ("IND") application"

An investigational new drug is a medication that is still being tested in clinical trials to determine if it is safe and effective for treating a specific condition. For investors, it represents a potential breakthrough that could lead to a new treatment and significant financial gains if successful, but also carries risks since it has not yet been approved for widespread use.

phase 2 study medical

"a "study may proceed" letter to proceed with a Phase 2 study"

A phase 2 study is a mid-stage clinical trial that tests whether an experimental drug or treatment actually works for the intended condition and continues to check safety in a larger group of patients than early trials. Think of it as a focused pilot test before a full market launch; positive or negative results strongly affect a drug’s chances of approval, the remaining development time and costs, and therefore an investment’s risk and potential value.

phase 1b study medical

"presented complete results from a Phase 1b study of PUR1800 for AECOPD"

A phase 1b study is an early-stage human clinical trial that follows initial safety testing and focuses on finding the right dose and seeing any early signs that a treatment might work in patients. Think of it as serving a new recipe to a small group of target diners to refine portion size and taste while watching for bad reactions. For investors, positive phase 1b results reduce scientific risk and can meaningfully raise a drug’s value, while negative results increase uncertainty and potential loss.

narrow spectrum kinase inhibitor medical

"PUR1800 is a Narrow Spectrum Kinase Inhibitor ("NSKI"), engineered with our iSPERSE™ technology"

A narrow spectrum kinase inhibitor is a drug that blocks the activity of a small, specific group of enzymes called kinases, which act like switches inside cells to control growth, division and survival. For investors, these drugs matter because targeting fewer enzymes can mean more precise effects, potentially fewer side effects and clearer clinical benefits for specific patient groups—making development risks, regulatory chances and market size easier to evaluate compared with broad-spectrum drugs.

idiopathic pulmonary fibrosis medical

"evaluation of the potential for Narrow Spectrum Kinase inhibitors as a treatment for Idiopathic Pulmonary Fibrosis"

Idiopathic pulmonary fibrosis is a chronic lung disease in which the air‑carrying tissue becomes progressively thickened and scarred for no identifiable reason, making the lungs stiff and less able to move oxygen—similar to a sponge that hardens and loses its pores. It matters to investors because it is life‑limiting with limited effective treatments, so clinical trial outcomes, regulatory approvals, pricing and reimbursement decisions can strongly affect the commercial value of therapies and the financial prospects of companies developing treatments.

central drug standard control organization regulatory

"approved by India's Central Drug Standard Control Organization to proceed with a Phase 3 clinical trial"

The central drug standard control organization is the national regulatory agency that sets safety and quality rules, reviews clinical trials and drug approvals, and oversees imports and manufacturing standards for medicines and medical products. Like a building inspector for drugs, it gives the official green light or stops products until safety and paperwork meet requirements; investors watch its decisions because approvals, delays or compliance actions directly affect a company’s ability to sell products and generate revenue.

AI-generated analysis. Not financial advice.

Pulmatrix continues to support Cullgen in seeking approval for their merger from the China Securities Regulatory Commission

FRAMINGHAM, Mass., Dec. 18, 2025 /PRNewswire/ -- Pulmatrix, Inc. ("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, today announced that Pulmatrix and Cullgen Inc. ("Cullgen") have mutually agreed to waive the "No Solicitation" clause in the Merger Agreement signed in November 2024 in order to permit each party to explore alternate transactions while continuing to work toward merger approval from the China Securities Regulatory Commission (the "CSRC").

Peter Ludlum, Interim Chief Executive Officer of Pulmatrix, commented, "Regarding the Merger Agreement that we signed in November 2024, our Form S-4 filing was declared effective in May 2025, and our stockholders approved the Merger Agreement and related transactions in June 2025. However, we have not yet received approval from the CSRC. Therefore, we feel that it is appropriate to explore any opportunistic transactions that may benefit our respective companies while still seeking approval from the CSRC."

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 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 is subject to certain closing conditions, including Nasdaq's approval of the listing of the shares of Pulmatrix common stock to be issued in connection with the Merger and approval from the China Security Regulatory Commission.  

If the proposed Merger is completed, the business of Cullgen will continue as the business of the combined company.

The Company's total cash and cash equivalents balance as of September 30, 2025, was $4.8 million. The Company anticipates that its cash position, based on current operational efficiencies and prioritization of spending, is sufficient to fund its operations into at least the fourth quarter of 2026.

Pulmatrix Clinical Assets and Proprietary iSPERSE™ Technology

iSPERSE™ Technology

• iSPERSE™ particles 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 September 30, 2025, Pulmatrix's patent portfolio related to iSPERSE™ included approximately 146 granted patents, 18 of which are U.S.-granted patents, plus approximately 50 pending patent applications in the U.S. and other jurisdictions.

PUR3100

• PUR3100 is an orally inhaled dihydroergotamine ("DHE") engineered with Pulmatrix's iSPERSE™ dry powder inhalation technology for the treatment of acute migraine and is a Phase 2-ready asset with 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 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 advised Pulmatrix that they have 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 will seek to monetize PUR1900 for indications where an orally inhaled antifungal may provide a therapeutic benefit or fulfill an unmet medical need.

About Pulmatrix, Inc.
Pulmatrix is 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. The Company's proprietary product pipeline includes treatments for central nervous system ("CNS") disorders such as acute migraine and serious lung diseases such as Chronic Obstructive Pulmonary Disease ("COPD") and allergic bronchopulmonary aspergillosis ("ABPA"). Pulmatrix's product candidates are based on its proprietary engineered dry powder delivery platform, iSPERSE™, which seeks to improve therapeutic delivery to the lungs by optimizing pharmacokinetics and reducing systemic side effects to improve patient outcomes.

For more on the Company's inhaled product candidates please visit:
https://www.pulmatrix.com/pipeline.html.

Forward-Looking Statements
Certain statements in this press release that are forward-looking and not statements of historical fact are forward-looking statements within the meaning of the federal securities laws. Such forward-looking statements include, but are not limited to, statements of historical fact and may be identified by words such as "anticipates," "assumes," "believes," "can," "could," "estimates," "expects," "forecasts," "guides," "intends," "is confident that," "may," "plans," "seeks," "projects," "targets," and "would," and their opposites and similar expressions are intended to identify forward-looking statements. Such forward-looking statements are based on the beliefs of management as well as assumptions made by and information currently available to management. Actual results could differ materially from those contemplated by the forward-looking statements as a result of certain factors, including, but not limited to, the consummation of and the exact timing of the proposed Merger with Cullgen, the receipt of applicable regulatory approvals in connection with the proposed Merger with Cullgen, and satisfaction of closing conditions thereunder, among others; the Company's ability to divest its clinical assets on terms favorable to the Company, or at all, the Company's ability to maintain compliance with the listing standards of the Nasdaq Capital Market; the Company's ability to conduct its business and raise capital in the future when needed; delays in planned clinical trials; the ability to establish that potential products are efficacious or safe in preclinical or clinical trials; the ability to establish or maintain collaborations on the development of therapeutic candidates; the ability to obtain appropriate or necessary governmental approvals to market potential products; the ability to obtain future funding for developmental products and working capital and to obtain such funding on commercially reasonable terms; the Company's ability to manufacture product candidates on a commercial scale or in collaborations with third parties; changes in the size and nature of competitors; the ability to retain key executives and scientists; the ability to secure and enforce legal rights related to the Company's products, including patent protection. A discussion of these and other factors, including risks and uncertainties with respect to the Company, including the proposed Merger with Cullgen, is set forth in the Company's filings with the Securities and Exchange Commission, including its most recent Annual Report on Form 10-K, as may be supplemented or amended by the Company's Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. The Company disclaims any intention or obligation to revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

Investor Contact:
Chuck Padala
Managing Director
LifeSci Advisors
646-627-8390
chuck@lifesciadvisors.com

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SOURCE Pulmatrix Inc.

FAQ

What did Pulmatrix (PULM) and Cullgen announce on December 18, 2025?

They mutually waived the No Solicitation clause to explore alternatives while continuing to pursue CSRC merger approval.

Has Pulmatrix shareholders approved the Cullgen merger (PULM)?

Yes; Pulmatrix stockholders approved the merger and related proposals on June 16, 2025.

What is Pulmatrix's cash runway reported on September 30, 2025 for PULM?

Pulmatrix reported $4.8 million and expects funds to support operations into at least Q4 2026.

What regulatory approvals remain before the Pulmatrix–Cullgen merger can close?

Closing is subject to CSRC approval and Nasdaq approval of the listing of shares to be issued in the merger.

What clinical progress does Pulmatrix report for PUR3100 (PULM)?

PUR3100 has an FDA-accepted IND and is described as Phase 2-ready with a Phase 2 protocol included.

What commercial arrangement exists for PUR1900 related to PULM?

Pulmatrix will receive 2% royalties on potential future net sales by Cipla outside the United States.