Gossamer Bio Reports Q1 2026 Financial Results and Highlights Recent Business Progress
Gossamer Bio has reported its financial results for the first quarter ended March 31, 2026, while also providing a major business update centered on the continued advancement of seralutinib, the company’s lead investigational therapy for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease (PH-ILD). The update highlighted significant regulatory progress, encouraging imaging data from the Phase 3 PROSERA study, and strategic financial restructuring initiatives designed to strengthen the company’s balance sheet ahead of a potential regulatory filing.
The company is jointly developing seralutinib with Chiesi Group under a global collaboration agreement that combines Gossamer’s pulmonary hypertension expertise with Chiesi’s international commercial capabilities. Together, the partners are working to position seralutinib as a potentially important therapy for patients suffering from serious pulmonary vascular diseases that remain associated with high morbidity and mortality despite currently available treatment options.
Gossamer management emphasized that the company is executing on multiple strategic priorities simultaneously, including regulatory engagement with the U.S. Food and Drug Administration (FDA), ongoing scientific analysis of the PROSERA dataset, and measures intended to improve the company’s long-term financial position.
Faheem Hasnain, Chairman, Co-Founder, and Chief Executive Officer of Gossamer Bio, stated that the company has secured an in-person Pre-NDA Type B meeting with the FDA, reflecting management’s confidence in the totality of evidence supporting seralutinib. According to Hasnain, the breadth of data generated from the PROSERA program, including clinical efficacy findings, imaging analyses, and safety observations, has reinforced the company’s belief that a regulatory path forward exists for a New Drug Application submission.
The FDA meeting is scheduled for mid-June 2026 and represents a key milestone for the company. Gossamer had previously anticipated pursuing a Type C meeting with the agency, but after continued analysis of the PROSERA results, the company elected instead to request a more formal Type B Pre-NDA meeting. This type of meeting allows for a comprehensive regulatory discussion regarding the potential submission package and supporting evidence required for approval consideration.
Subject to the outcome of that meeting, Gossamer expects to submit a New Drug Application for seralutinib in pulmonary arterial hypertension during September 2026. If the application is accepted for filing by the FDA, the company believes seralutinib could potentially receive regulatory approval in the third quarter of 2027.
Seralutinib is an inhaled therapy designed to inhibit platelet-derived growth factor receptor (PDGFR), colony-stimulating factor 1 receptor (CSF1R), and c-KIT signaling pathways. Unlike traditional vasodilator-based PAH therapies, seralutinib is intended to target the underlying proliferative, inflammatory, and fibrotic mechanisms involved in pulmonary vascular remodeling.
Pulmonary arterial hypertension is a progressive and life-threatening disease characterized by narrowing and remodeling of the pulmonary arteries, which leads to increased pressure within the lungs and eventual right heart failure. Although several approved therapies exist, most primarily focus on vasodilation rather than directly addressing the structural remodeling processes that drive disease progression.
Gossamer’s latest update placed particular emphasis on findings from the exploratory CT functional respiratory imaging, or FRI, substudy within the Phase 3 PROSERA trial. The substudy included 162 participants and generated what the company described as the broadest multi-compartment imaging dataset reported to date from a controlled therapeutic study in pulmonary hypertension.
According to the company, the imaging results demonstrated statistically significant exploratory treatment effects across arterial, venous, fibrosis-related, and vascular complexity parameters. Management believes these findings provide additional evidence that seralutinib may exert biological effects throughout multiple compartments of the lung rather than solely within the pulmonary arteries.
The arterial findings were especially important because they built upon remodeling signals previously identified in earlier seralutinib studies. In the PROSERA substudy, seralutinib demonstrated a statistically significant reduction in the proportion of blood volume within larger arterial vessels compared with placebo. The company stated that this observation is consistent with proximal decompression and arterial remodeling in a broader Phase 3 patient population.
Importantly, the PROSERA analysis extended beyond the arterial compartment to evaluate additional aspects of pulmonary vascular biology. Gossamer reported statistically significant increases in total venous blood volume and small venous vessel volume among patients receiving seralutinib. The company also observed reductions in fibrosis-like tissue within the lung parenchyma, along with increased venous vascular fractal dimension, which may indicate greater vascular complexity and improved microvascular architecture.
These findings are notable because pulmonary arterial hypertension has traditionally been viewed primarily as a disease affecting pulmonary arteries. However, growing evidence from pathological and imaging research suggests that additional biological processes—including impaired microvascular perfusion, inflammation, fibrosis, and venous abnormalities—also contribute to disease progression.
Gossamer believes the imaging signals observed in PROSERA may provide structural evidence supporting seralutinib’s proposed mechanism of action across multiple disease pathways. The company noted that the therapy’s non-vasodilatory profile targets inflammatory, proliferative, and fibrotic pathways that may influence both the pulmonary vasculature and surrounding lung tissue.
The company further stated that imaging changes observed in the substudy correlated with favorable clinical outcomes. Improvements in imaging parameters were associated with changes in pulmonary hemodynamics, NT-proBNP levels, six-minute walk distance, and REVEAL Lite 2 risk scores. These correlations may help reinforce the biological relevance of the imaging data and provide additional support for the overall clinical findings generated by the PROSERA program.
While the p-values reported in the substudy were nominal and not adjusted for multiplicity, Gossamer emphasized that the consistency between imaging results, clinical measures, and mechanistic expectations strengthens the overall evidence package supporting seralutinib.
Alongside the scientific and regulatory update, Gossamer also announced a major financial restructuring initiative involving its outstanding convertible debt. The company launched an exchange offer related to its 5.00% Convertible Senior Notes due 2027, which currently represent approximately $200 million in aggregate principal outstanding.
Under the proposed exchange structure, noteholders would receive a combination of common stock or prefunded warrants, newly issued 7.50% Senior Secured First Lien Convertible Notes due 2030, and, for early participants, warrants to purchase additional common stock.
For every $1,000 principal amount of existing notes tendered, holders would receive approximately 1,588 shares of common stock or equivalent prefunded warrants, $360 principal amount of the new secured notes, and 750 purchase warrants if tendered before the early participation deadline.
The newly proposed notes would mature in July 2030 and carry a 7.50% annual interest rate payable semi-annually in cash. The securities would also be secured by a first-priority lien on substantially all assets of the company and its subsidiaries. Meanwhile, the purchase warrants would become exercisable beginning six months after issuance and remain active through the fifth anniversary of issuance.
The exchange offer is intended to materially reduce Gossamer’s outstanding convertible debt burden. If all eligible noteholders participate, the company estimates its convertible indebtedness would decline from $200 million to approximately $72 million, representing a reduction of $128 million.
Management stated that the restructuring initiative is designed to extend the company’s debt maturity profile and strengthen the balance sheet as seralutinib approaches a potential NDA submission and possible commercialization phase.
The proposal has already received significant support from existing noteholders. According to the company, holders representing approximately 75.2% of the outstanding notes have entered into a transaction support agreement indicating their intention to participate in the exchange offer.
The exchange offer also includes a related consent solicitation process intended to amend the indenture governing the existing notes. Proposed amendments would eliminate substantially all restrictive covenants and certain default provisions associated with the current debt structure.
Gossamer indicated that the new notes will include a minimum cash covenant of $40 million, although this requirement could step down if the company achieves certain financing thresholds and if the FDA accepts the seralutinib NDA for filing.
In addition to business and financing developments, the company reported first-quarter financial results reflecting ongoing investment in late-stage development activities.
As of March 31, 2026, Gossamer held approximately $99.2 million in cash, cash equivalents, and marketable securities. The company stated that its existing financial resources are expected to support operating and capital expenditures into the first quarter of 2027.
Revenue associated with the collaboration agreement with Chiesi totaled $17.0 million during the quarter, including $9.3 million in cost reimbursement revenue. This compares with $9.9 million in collaboration revenue during the same period in 2025.
Research and development expenses increased to $43.1 million during the first quarter of 2026 compared with $38.0 million in the prior-year period. The increase was primarily attributed to clinical trial activities associated with seralutinib development.
General and administrative expenses also rose significantly to $18.7 million compared with $8.7 million during the same quarter of 2025. According to the company, the increase was primarily driven by one-time severance and related charges associated with a previously announced workforce reduction.
Net loss for the quarter totaled $46.7 million, or $0.20 per basic share, compared with a net loss of $36.6 million, or $0.16 per basic share, during the corresponding period last year.
Despite the higher quarterly loss, Gossamer executives emphasized that the company remains focused on disciplined execution as it advances seralutinib toward potential regulatory review and prepares for the next stage of corporate growth. With a pivotal FDA interaction approaching, expanding evidence from the PROSERA program, and efforts underway to strengthen the balance sheet, the company appears increasingly focused on positioning seralutinib for possible commercialization in pulmonary arterial hypertension.
About Gossamer Bio
Gossamer Bio is a clinical-stage biopharmaceutical company focused on the development and commercialization of seralutinib for the treatment of pulmonary arterial hypertension and pulmonary hypertension associated with interstitial lung disease. Its goal is to be an industry leader in, and to enhance the lives of patients living with, pulmonary hypertension.
