Sutro Biopharma (STRO) investor relations material

Executive summary

• Focused on developing site-specific and novel-format ADCs for oncology, with STRO-004 as the lead candidate in Phase 1 trials and additional preclinical assets STRO-006 and STRO-227 advancing toward IND submissions.

• Strategic portfolio review and restructuring in 2025 led to deprioritization and closure of the luveltamab tazevibulin program, a two-thirds workforce reduction, and a shift to external manufacturing, reallocating resources to the core pipeline.

• Collaboration with Astellas and Vaxcyte continues to provide milestone payments and technical support revenue, including a $10M milestone for the first dual-payload iADC entering the clinic.

• First dual-payload iADC from the platform entered clinic via Astellas collaboration, with a second program in IND-enabling studies.

• Presented new preclinical data at AACR, highlighting pipeline progress.

Financial highlights

• Revenue for Q1 2026 was $14.5M, down 17% year-over-year, primarily due to lower Astellas and Vaxcyte collaboration revenue.

• Net loss for Q1 2026 was $38.5M, a 49% improvement from $76.0M in Q1 2025, reflecting reduced R&D and G&A expenses post-restructuring.

• Operating expenses decreased 49% year-over-year to $44.2M, with R&D and G&A expenses for Q1 2026 at $44.1M, down from $64.9M in Q1 2025.

• Cash, cash equivalents, and marketable securities totaled $202.6M as of March 31, 2026, up from $141.4M at year-end 2025.

• Gross proceeds of $110M were raised in a February 2026 public offering, extending cash runway into at least Q2 2028.

Outlook and guidance

• Cash runway expected to fund operations for at least 12 months from the filing date and projected into at least Q2 2028, excluding future milestones.

• Anticipates reporting preliminary Phase 1 data for STRO-004 in mid-2026 and advancing STRO-006 and STRO-227 toward IND submissions in 2026.

• Expects operating expenses to decrease in 2026 due to strategic reprioritization, but may rise longer-term as pipeline advances.