Entered an exclusive license agreement with Innovent Biologics for SP001, a Phase 2-ready, third-generation anti-CD40L antibody for immune-mediated diseases

U.S. Food and Drug Administration approved Utebzi^™ (tebipenem pivoxil), the first and only oral carbapenem antibiotic for adults with complicated urinary tract infections (cUTIs), including pyelonephritis

Closed $105 million non-recourse, non-dilutive financing backed by a portion of future Utebzi milestones and royalties, extending cash runway into the second half of 2029

Appointed Debra Zack, M.D., Ph.D., as Chief Medical Officer

Conference call today at 5pm EDT

In July 2026, Spero entered into an exclusive license agreement with Innovent Biologics, Inc. for SP001. Spero gained exclusive rights to develop, research, manufacture, and commercialize SP001 worldwide, excluding Greater China (Mainland China, Hong Kong, Macau, and Taiwan), where Innovent retains rights.

SP001 is a third-generation, fully humanized, Fc-silent IgG1 monoclonal antibody targeting CD40L, an upstream immune activation signal involved in T-cell, B-cell, antigen-presenting cell, and platelet biology. Innovent completed two healthy volunteer Phase 1 trials, a single ascending dose (“SAD”) study and a multiple ascending dose (“MAD”) study, as well as a Phase 1b MAD study in patients with primary Sjögren’s disease (“SjD”). Data from the Phase 1b SjD study were presented in a poster session at the EULAR 2026 Congress.

Spero plans to advance SP001 into a Phase 2 study in IgG4-related disease (IgG4-RD), a serious, rare chronic fibroinflammatory disease with significant treatment burden and limited therapeutic options.

In June 2026, Spero and GSK announced that the U.S. Food and Drug Administration (FDA) approved Utebzi for the treatment of complicated urinary tract infections (cUTIs), including pyelonephritis, caused by certain susceptible pathogens in adult patients who have limited or no alternative oral treatment options. Utebzi is the first and only oral carbapenem antibiotic approved for these patients. The product is expected to be made available by GSK to U.S. patients by the end of 2026. GSK holds commercialization rights in the U.S. and Europe.

In July 2026, Spero announced a non-recourse, non-dilutive royalty financing with affiliates of HealthCare Royalty Partners, a business of KKR (HCRx), for $105 million in gross proceeds, in exchange for rights to a portion of the anticipated payments from sales of Utebzi owing from GSK (GSK Proceeds).

The transaction is structured as a non-recourse Note Purchase and Guaranty Agreement (NPA) generally payable solely from the GSK proceeds, and a Royalty and Milestone Payment Interest Purchase and Sale Agreement (RPA) under which the Company may retain 35% interest in the GSK Proceeds arising after required payments under the NPA, preserving potential long-term upside from the asset.

The proceeds will primarily support advancement of SP001.

In July 2026, Spero announced the appointment of Debra Jeske Zack, M.D., Ph.D., as Chief Medical Officer. Dr. Zack is a board-certified rheumatologist with a Ph.D. in immunology and brings more than 25 years of leadership in developing therapeutics for immune-mediated diseases. She will oversee Spero’s clinical development strategy and organization as the Company advances its immunology program.

Spero reported a net loss of $9.6 million for the second quarter of 2026 compared to a net loss of $1.7 million for the second quarter of 2025, or a diluted net loss per share of common stock of $0.16 and $0.03, respectively.

No revenue was recognized for the second quarter of 2026, compared to total revenue of $14.2 million for the second quarter of 2025, as all deferred revenue under the collaboration agreements was recognized in prior periods and all grant revenue has been fully recognized, and the awards have been completed and closed out.

Research and development expenses for the second quarter of 2026 were $3.4 million, compared to $10.7 million of research and development expenses for the same period in 2025. The decrease in research and development expenses was a result of decreased clinical activities related to our pivotal Phase 3 clinical trial of Utebzi, which was stopped early for efficacy in the first half of 2025, and a decrease in personnel related costs.

General and administrative expenses for the second quarter of 2026 were $6.5 million, compared to $5.9 million of general and administrative expenses for the same period in 2025. The increase was a result of increased legal and business development costs, offset partially by a decrease in personnel related costs.

As of June 30, 2026, cash and cash equivalents were $50.8 million. This balance does not reflect the proceeds from the royalty financing completed in July 2026.

The company expects that its cash and cash equivalents at June 30, 2026, together with the proceeds of the royalty financing, will be sufficient to fund operating expenses and capital expenditure into the second half of 2029.

Cash and cash equivalents

Other assets

Total assets

Total liabilities

Total stockholder’s equity

Total liabilities and stockholders’ equity

Revenues:

Grant revenue

Collaboration revenue - related party

Collaboration revenue

Total revenues

Operating expenses:

Research and development

General and administrative

Restructuring

Total operating expenses

Loss from operations

Total other income, net

Net loss

Net loss per share attributable to common shareholders per share, basic and diluted

Weighted average shares outstanding, basic and diluted: