• To evaluate the safety and tolerability of escalating doses of ERAS-801 in study participants with recurrent glioblastoma multiforme (GBM).
• To determine the Maximum Tolerated Dose (MTD) and/or Recommended Dose (RD) of ERAS-801.
• To evaluate the antitumor activity of ERAS-801.
• To evaluate the PK profile of ERAS-801.

This is a Phase 1, open-label, multicenter clinical study evaluating ERAS-801 as a monotherapy. The study will initially commence with dose escalation of ERAS-801 in study participants with recurrent GBM. Once the MTD and/or RD has been determined from dose escalation, then dose expansion of ERAS-801 may commence in study participants with recurrent GBM harboring alterations in epidermal growth factor receptor (EGFR).

Inclusion Criteria:

• Age ≥ 18 years
• Willing and able to give written informed consent
• Diagnosis of Glioblastoma, IDH WT as defined by the WHO 2021 criteria
• Adequate organ function
• Willing to comply with all protocol-required visits, assessments, and procedures
• Able to swallow oral medication

Exclusion Criteria:

• Prior treatment with an EGFR inhibitor for Glioblastoma
• Currently enrolled in another therapeutic study
• History of clinically significant cardiovascular disease
• Gastrointestinal conditions that may affect administration/absorption of oral medications
• Have an active infection (bacterial, fungal, or viral) requiring systemic therapy
• Pregnant or breastfeeding women
• Any serious underlying medical or psychiatric condition or evidence of any other significant clinical disorder or laboratory finding that renders the patient inappropriate to participate in the study
• Known allergies, hypersensitivity, or intolerance to ERAS-801 or its excipients