A Phase 3 Study to Evaluate Petosemtamab Compared With Investigator's Choice Monotherapy in Previously Treated Head and Neck Squamous Cell Carcinoma Patients (LiGeR-HN2)

Inclusion Criteria

• Signed ICF before initiation of any study procedures.
• Age ≥ 18 years at signing of ICF.
• Histologically previously confirmed HNSCC with evidence of metastatic or locally advanced disease not amenable to standard therapy with curative intent.
• HNSCC participants progressed on or after anti-PD-1 therapy and platinum-containing therapy.
• The eligible HNSCC primary tumor locations are oropharynx, oral cavity, hypopharynx, and larynx.
• Documentation of p16 status (positive or negative) by local laboratory IHC for participants with primary oropharyngeal cancer.
• A baseline new tumor sample unless the participant has an available tumor sample as an FFPE block with sufficient material.
• Measurable disease as defined by RECIST v1.1 by radiologic methods.
• ECOG PS of 0 or 1
• Life expectancy ≥ 12 weeks, as per investigator
• Adequate organ function (as per protocol)

Exclusion Criteria

• Central nervous system metastases that are untreated or symptomatic, or require radiation, surgery, or continued steroid therapy to control symptoms within 14 days prior to randomization.
• Known leptomeningeal involvement
• Any systemic anticancer therapy within 4 weeks prior to randomization.
• Major surgery within 3 weeks or palliative radiotherapy within 2 weeks prior to randomization.
• Persistent Grade >1 clinically significant toxicities related to prior antineoplastic therapies
• History of hypersensitivity reaction to any of the excipients of treatment required for this study.
• Unstable angina; history of congestive heart failure of Class II-IV New York Heart Association (NYHA) criteria, or serious cardiac arrhythmia requiring treatment or history of myocardial infarction within 6 months of study entry
• History of prior malignancies with the exception of localized cancer with curative resection (e.g. cervical intraepithelial neoplasia or nonmelanoma skin cancer)
• Current dyspnea at rest of any origin, or other diseases requiring continuous oxygen therapy
• Current serious illness or medical conditions including, but not limited to, uncontrolled active infection, clinically significant pulmonary, metabolic or psychiatric disorders
• Participants with known infectious diseases (as per protocol)
• Pregnant or breastfeeding participants
• Participant has a primary tumor site of nasopharynx (any histology).