Non-randomized, open-label

Part 1: monotherapy bemarituzumab dose exploration
Part 2: monotherapy bemarituzumab dose expansion

• Number of patients who experience dose-limiting toxicity (part 1)
• Number of patients who experience treatment-emergent adverse events (part 1)
• Number of patients who experience treatment-related adverse events (part 1)
• Objective response rate (part 2)

1. Age ≥ 18 years (or legal adult age within country, whichever is older) at the time that the Informed Consent Form (ICF) is signed
2. Histologically or cytologically confirmed cancer of one of the following types, refractory to or relapsed after at least 1 prior standard therapeutic regimen in the advanced/metastatic setting, as specified below. If no standard of care therapies exist for the participant, or the participant cannot tolerate or refuses standard of care anticancer therapy, the participant may be allowed to participate on the study after discussion between the investigator and Amgen medical monitor.
   Participants who have not received all approved or standard treatments for their cancer must be informed that these alternatives to receiving bemarituzumab are available prior to consenting to participate in the trial.
   o lung adenocarcinoma: at least platinum-based chemotherapy, checkpoint inhibitor, and targeted therapy
3. Disease that is unresectable, locally advanced, or metastatic (not amenable to curative therapy)
4. Tumor overexpresses FGFR2b as determined by centrally performed immunohistochemistry (IHC) testing
5. Measurable disease per Response Evaluation Criteria in Solid Tumors Version 1.1
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
7. Adequate organ function as determined per protocol

1. Untreated or symptomatic central nervous system (CNS) metastases or leptomeningeal disease.
2. Impaired cardiac function or clinically significant cardiac disease including: unstable angina within 6 months prior to first dose of study treatment, acute myocardial infarction ≥ 6 months prior to first dose of study treatment, New York Heart Association (NYHA) class II-IV congestive heart failure, uncontrolled hypertension (defined as an average systolic blood pressure ≥ 160 mmHg or diastolic ≥ 100 mmHg despite optimal treatment, uncontrolled cardiac arrhythmias requiring anti-arrhythmic therapy other than beta blockers or digoxin, active coronary artery disease or corrected QT interval QTc ≥ 470
3. History of systemic disease or ophthalmologic disorders requiring chronic use of ophthalmic steroids
4. Evidence of any ongoing ophthalmologic abnormalities or symptoms that are acute (within 4 weeks) or actively progressing
5. Unwillingness to avoid use of contact lenses during study treatment and for at least 100 days after the end of treatment
6. Recent (within 6 months) corneal surgery or ophthalmic laser treatment or recent (within 6 months) history of, or evidence of, corneal defects, corneal ulcerations, keratitis, or keratoconus, or other known abnormalities of the cornea that may pose an increased risk of developing a corneal ulcer prior/concomitant therapy
7. Prior treatment with any investigational selective inhibitor of the fibroblast growth factor (FGF)/FGF receptor pathway (unless approved standard of care for tumor indication).