Study to Assess an Anti-Trop2 Antibody Drug Conjugate in Relapsed or Refractory Solid Tumors

Inclusion Criteria:

* Histologically or cytologically confirmed advanced cancer that is relapsing or refractory to at least one prior treatment and not a candidate for other treatments or is intolerant to established treatments.
* At least one measurable disease per Response Evaluation Criteria in Solid Tumors v. 1.1 (RECIST 1.1).
* Eastern Cooperative Oncology Group Performance Status ≤ 2.
* Must have a life expectancy of ≥ 6 months.
* Must have adequate bone marrow, hepatic and renal function as assessed by specific laboratory tests.
* Must be recovered ≤ Grade 1 from acute toxicities from previous therapies, excluding alopecia and vitiligo.
* Has not had prior treatment within 2 weeks of screening with high dose corticosteroids.
* Be willing and able to comply with the study schedule and all study requirements.
* Willing to follow all contraception guidelines.

Exclusion Criteria:

* Previous treatment with any systemic therapy or investigational drug within 2 weeks of the first dose of study drug.
* Currently participating in any other interventional clinical study.
* Has a diagnosis of other malignancies if the malignancy has required therapy within the last 3 years or is not in complete remission.
* Has presence of bulky disease defined as any mass \> 7 cm in greatest dimension will trigger a discussion with the medical monitor.
* Has left ventricular ejection fraction (LVEF) \< 40%.
* New York Heart Association (NYHA) Class ≥ 3.
* Has prolonged QTcF interval on an electrocardiogram.
* Has spinal cord compression or clinically active brain metastases.
* Has a history of Sacituzumab govitecan treatment.
* History of anaphylactic reaction to irinotecan or ≥ Grade 3 toxicity to prior irinotecan treatment.
* Has active or prior COVID-19 infection, with symptoms presenting within 4 weeks of the first dose of study drug.
* Has an active bacterial, viral, or fungal infection.
* Is currently pregnant or breast feeding or planning on either during the study.
* Has chronic or moderate chronic obstructive pulmonary disease or other chronic respiratory conditions unless receiving treatment and stable for 3 months prior to screening.
* Has known HIV or acquired immunodeficiency syndrome-related illness, acute or history of chronic hepatitis B or C.
* Has any significant medical condition, abnormality, or psychiatric illness that would prevent study participation.