Pulmatrix Inc. announced plans to divest its clinical assets and proprietary iSPERSE technology as part of its upcoming merger with Cullgen, a privately held biopharmaceutical company specializing in targeted protein degradation. The merger, expected to close in June 2025, will create a Nasdaq-listed company focused on Cullgen's uSMITE platform with three degrader programs already in Phase 1 clinical trials.
Peter Ludlum, Interim Chief Executive Officer of Pulmatrix, stated, "Our focus in the first quarter has been to advance steps to complete the proposed merger with Cullgen. If successful, the proposed merger would create a Nasdaq-listed company focusing on targeted protein degradation technology with three degrader programs in Phase 1 clinical trials – two for the treatment of cancer and one for the treatment of acute and chronic pain."
The Securities and Exchange Commission (SEC) has declared the registration statement for the proposed merger effective, with the transaction anticipated to close next month subject to satisfaction of closing conditions.
Assets Being Divested
PUR3100 for Acute Migraine
Among the assets being divested is PUR3100, an orally inhaled dihydroergotamine (DHE) formulated using Pulmatrix's iSPERSE dry powder inhalation technology for treating acute migraine. The FDA accepted an Investigational New Drug application for PUR3100 in 2023, positioning it as Phase 2-ready.
Phase 1 trial results, published in 2024 in Headache: The Journal of Head and Face Pain, demonstrated that PUR3100 achieved peak exposures in the targeted therapeutic range with maximum concentration occurring just five minutes after dosing. Notably, patients receiving PUR3100 experienced a lower incidence of nausea and no vomiting compared to those receiving intravenously administered DHE.
PUR1800 for COPD Exacerbations
Another asset in the divestment plan is PUR1800, a Narrow Spectrum Kinase Inhibitor engineered with iSPERSE technology for treating acute exacerbations in chronic obstructive pulmonary disease (AECOPD). Complete results from a Phase 1b study presented in 2023 indicated PUR1800 was safe and well-tolerated with no observed safety signals.
The topline data, combined with results from chronic toxicology studies, support continued development for AECOPD and other inflammatory respiratory diseases.
PUR1900 Antifungal Treatment
PUR1900, an inhaled iSPERSE formulation of the antifungal drug itraconazole, is also part of the divestment plan. Pulmatrix completed all Phase 2b wind-down activities in Q3 2024 and no longer bears financial responsibility for its development.
The company's partner Cipla has continued clinical development outside the United States, completing a Phase 2 study in India and receiving approval from India's Central Drug Standard Control Organization to proceed with a Phase 3 clinical trial. Should Cipla successfully market PUR1900 outside the U.S., Pulmatrix will receive 2% royalties on any future net sales.
iSPERSE Technology Platform
The proprietary iSPERSE technology platform itself is also being divested. This innovative particle engineering technology creates dry powder formulations that overcome limitations of conventional inhaled technologies.
iSPERSE particles are engineered with a small, dense, and dispersible profile that exceeds the performance of traditional dry powder particles, offering superior drug delivery compared to traditional oral and injectable forms of treatment.
As of March 31, 2025, Pulmatrix's patent portfolio related to iSPERSE included approximately 146 granted patents (18 in the U.S.) with expiration dates from 2026 to 2037, plus approximately 48 additional pending patent applications globally.
Financial Results
Pulmatrix reported first quarter 2025 financial results showing significant changes from the previous year:
- Revenues decreased to $0 for Q1 2025, compared to $5.9 million for Q1 2024, primarily due to the completion of the PUR1900 Phase 2b clinical trial wind-down
- Research and development expenses decreased to less than $0.1 million from $3.5 million in the same period last year
- General and administrative expenses increased to $1.8 million from $1.6 million, primarily due to costs related to the proposed merger
- Cash and cash equivalents balance as of March 31, 2025, was $7.7 million
The company anticipates that its current cash position is sufficient to fund operations at least through the anticipated closing of the proposed merger with Cullgen.
Future Direction
If the merger proceeds as planned, the resulting company will shift focus to Cullgen's proprietary targeted protein degradation uSMITE platform. This technology is being used to discover and advance therapeutics for cancer and other diseases, with three degrader programs already in Phase 1 clinical trials – two for cancer treatment and one for acute and chronic pain.
The divestment of Pulmatrix's assets represents a significant strategic shift for the company, which has historically focused on developing novel inhaled therapeutic products for migraine and respiratory diseases using its iSPERSE technology.
Industry analysts will be watching closely to see which companies may acquire these clinical-stage assets, particularly the Phase 2-ready PUR3100 for acute migraine, which demonstrated promising pharmacokinetic profiles and reduced side effects compared to intravenous administration in early studies.
