AGX101 is an antibody-drug conjugate (ADC) therapy for tumor-forming cancers. The purpose of this study is to learn about AGX101 effects and safety at various dose levels in an all-comers advanced solid cancer patient population. AGX101will be administered intravenously.

Dosing of AGX101 will be repeated once every 3, 6 or 9 weeks. Participants may continue study treatment until disease progression, unacceptable toxicity, or consent withdrawal. Subjects will attend an end of treatment visit and will receive two safety follow-up telephone contacts up to 90 days following the last dose of study drug.

Inclusion Criteria:

• Histologically confirmed unresectable, locally advanced, or metastatic solid tumors.
• Refractory to or relapsed after all standard therapies known to provide proven clinical benefit, unless the patient is not a candidate for standard treatment, there is no standard treatment, or the patient refuses standard treatment after expressing an understanding of all available therapies with proven clinical benefit
• Willing to authorize use of existing archival tissue, unless otherwise discussed with Sponsor
• Time since the last dose of prior therapy to treat underlying malignancy (including other investigational therapy): Systemic cytotoxic chemotherapy: ≥ the duration of the most recent cycle of the previous regimen (with a minimum of 2 weeks for all, except 6 weeks for systemic nitrosourea or systemic mitomycin-C); Biologic therapy (eg, antibodies): ≥ 3 weeks; Small molecule therapies: ≥ 5 × half-life
• Have an ECOG performance status of 0 to 1
• Have adequate organ function
• LVEF ≥ 50%, as determined on cardiac ECHO or cardiac multiple-gated acquisition (MUGA) scan
• Highly effective contraception for both male and female patients throughout the study

Exclusion Criteria:

• Colorectal cancer patients with an unresected primary colorectal tumor and non-small-cell lung cancer with predominant squamous histology (ie, squamous cell carcinoma of the lung) are excluded unless otherwise discussed and approved by Sponsor
• Clinically unstable central nervous system (CNS) tumors or brain metastasis (stable and/or asymptomatic CNS metastases allowed)
• Have not recovered to ≤ Grade 1 or baseline from all AEs due to previous therapies (patients with ≤ Grade 2 neuropathy, endocrine-related irAEs, or other AEs may be eligible after discussion with the Sponsor)
• Has an active vasculitis that has required systemic treatment in the past 2 years prior to starting study treatment
• Significant (ie, ≥ Grade 2) ocular disturbances
• Variceal bleeding within 6 months prior to treatment, currently untreated or incompletely treated varices with bleeding, or who otherwise are at a high risk of bleeding
• Any other concurrent antineoplastic treatment except for allowed local radiation of lesions for palliation (to be considered non-target lesions after treatment) and hormone ablation
• Uncontrolled or life-threatening symptomatic concomitant disease, including known symptomatic HIV positive with an AIDS defining opportunistic infection within the last year, known symptomatic active hepatitis B or C, or known active tuberculosis
• Has undergone a major surgery within 3 weeks prior to starting study treatment or has inadequate healing or recovery from complications of surgery prior to starting study treatment
• Has received prior radiotherapy within 2 weeks prior to starting study treatment
• Has or had a potentially life-threatening second malignancy requiring systemic treatment within the last 3 years, or which would impede evaluation of treatment response
• Clinically significant cardiovascular disease
• Patients on a potent CYP3A inhibitor or CPY3A inducer who cannot be changed to another medication
• Has an active infection requiring concurrent systemic antibiotic therapy
• A woman of child-bearing potential (WOCBP) who has a positive pregnancy test prior to treatment
• Is breastfeeding or expecting to conceive or father children within the projected duration of the study