Spero Therapeutics (SPRO) 3rd Annual Guggenheim Healthcare Innovation Conference summary

Pipeline and financing

• First drug recently approved and partnered with GSK; development focus now SP001, an anti-CD40 ligand antibody in-licensed from Innovent in July.

• In-licensing included $105 million in non-recourse, non-dilutive funding; cash balance was ~$50 million as of June, supporting runway into H2 2029.

• CD40L may address innate and adaptive immune pathways; SP001’s silent Fc is designed to avoid the thromboembolic risk associated with active-Fc first-generation antibodies.

• In a preclinical anti-KLH mouse head-to-head study, SP001 was more potent than frexalimab; clinical confirmation is still needed.

• Healthy-volunteer, Sjögren’s, and chronic toxicology data will inform dose selection; SP001 has been tested in about 100 human subjects.

Sjögren’s data and development

• Innovent’s phase Ib trial enrolled about 30 patients, tested 7.5, 15, and 30 mg/kg, and used an 8:2 active-to-placebo ratio; primary endpoint was safety and tolerability.

• SP001 was tolerated across doses, with dose-dependent PK; all three doses showed placebo-adjusted ESSDAI and ESSPRI responses while placebo arms worsened.

• Innovent guided to initiating a phase II Sjögren’s trial by early 2027.

• Upper respiratory infections are an expected monitoring consideration for an immune modulator; no dose-dependent pattern was observed in the reported trial.

IgG4-RD strategy and trial

• IgG4-RD is a chronic, multi-organ fibroinflammatory disease; SP001’s upstream CD40L mechanism may address progressive disease and fibrosis beyond flare reduction.

• Planned phase II to start in Q2 2027: open-label, two doses, six months of treatment; primary endpoint is the validated IgG4-RD responder index, with safety, tolerability, and biomarkers assessed.

• Responder-index changes and biomarkers will guide a phase III decision; registrational endpoints are tied to flare reduction.

• Non-IV formulations will be explored.