SLR-108 PET Imaging in Subjects With Metastatic Solid Tumors

Inclusion Criteria * Men or women (as appropriate for cancer type) of age ≥18 years. * Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2. * Histologically or cytologically confirmed diagnosis of solid tumor as documented in medical records. * Based on the most recent tumor assessment, presence of metastatic disease that has progressed during or following previous treatment. * Presence of radiographically measurable disease (defined as the presence of ≥1 non-osseous tumor lesion that measures ≥10 mm in longest dimension \[≥15 mm in shortest dimension for lymph nodes\] and is outside of any prior radiation field). * Prior receipt of commercially available therapies that are indicated for the subject's cancer and have a demonstrated survival benefit for that indication. * Availability of tumor tissue from fresh tumor biopsy obtained by a core needle, excisional, or incisional biopsy; or punch biopsy (for cutaneous disease); or archival sample from a previous biopsy. * Completion of all previous therapy (including surgery, radiotherapy, chemotherapy, targeted therapy, immunotherapy, or investigational therapy) for the treatment of cancer ≥1 week before study drug administration. * Adequate hematological profile. * Adequate coagulation profile. * Adequate hepatic profile. * Adequate renal function. * Negative viral serology or adequate therapy for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection. * For female subjects of childbearing potential, a negative serum pregnancy test. * For female subjects of childbearing potential, willingness to use a protocol recommended method of contraception from the start of the screening period until ≥6 months after study drug administration. * For male subjects who can father a child and are having intercourse with females of childbearing potential who are not using adequate contraception, willingness to use a protocol recommended method of contraception from the start and until ≥6 months after study drug administration and to refrain from sperm donation from the start and until ≥12 months after study drug administration. * Willingness and ability of the subject to comply with scheduled visits, the drug administration plan, protocol-specified laboratory tests, other study procedures (including any required tumor biopsy/aspirations and all radiographic studies), and study restrictions. * Evidence of a personally signed informed consent indicating that the subject is aware of the neoplastic nature of the disease and has been informed of the procedures to be followed, the experimental nature of the study drug, alternatives, potential risks and discomforts, potential benefits, and other pertinent aspects of study participation. Exclusion Criteria: * Malignancy involving the central nervous system unless brain metastases have been previously treated with radiotherapy, have been stable for ≥4 weeks, and do not require corticosteroids. * Presence of another cancer with disease manifestations or therapy that could adversely affect subject safety or longevity, create the potential for drug-drug interactions, or compromise the interpretation of study results. * Uncontrolled ongoing systemic bacterial, fungal, or viral infection (including upper respiratory tract infection) at the time of study drug administration. * Significant cardiovascular event or comorbidity. * Significant screening ECG abnormalities. * Pregnancy or breastfeeding. * Any medical condition preventing PET/CT scanning, and/or inability to tolerate up to 60 minutes of PET/CT scanning per imaging session, and/or ineligibility for PET/CT scanning due to the weight limits of the scanner. * Major surgery within 4 weeks before study drug administration. * Use of a drug known to prolong the QT interval within 7 days prior to study drug administration. * Anticipated use of a strong inhibitor or inducer of cytochrome CYP3A4 or CYP1A2. * Concurrent participation in another therapeutic or imaging clinical trial. * Any illness, medical condition, organ system dysfunction, or social situation, including mental illness or substance abuse, deemed by the investigator to be likely to interfere with a subject's ability to provide informed consent, adversely affect the subject's ability to cooperate and participate in the study, or compromise the interpretation of study results.