This study is being done to:

• test the safety of OTL38
• see if OTL38 helps light up the cancer when viewed with the special camera system
• test the safety of the special camera system for use along with OTL38 during surgery

Inclusion Criteria:

1. Female patients 18 years of age and older

2. Have a primary diagnosis, or at high clinical suspicion, of primary ovarian cancer (of epithelial type), planned for primary debulking or interval debulking surgery, and:

   • Who are scheduled to undergo laparotomy for the debulking surgery OR
   • Who are scheduled to undergo laparoscopy and pre-authorized to undergo laparotomy for the debulking surgery, if cancer is detected on the laparoscopy

3. A negative serum pregnancy test at Screening followed by a negative urine pregnancy test on the day of surgery or day of admission for female patients of childbearing potential

4. Female patients of childbearing potential or less than 2 years postmenopausal agree to use an acceptable form of contraception from the time of signing informed consent until 30 days after study completion

5. Ability to understand the requirements of the study, provide written informed consent and authorization of use and disclosure of protected health information, and agree to abide by the study restrictions and to return for the required assessments

Exclusion Criteria:

1. Previous exposure to OTL38
2. Known FR alpha-negative ovarian cancer
3. Planned surgical approach via laparoscopy or robotic surgery
4. Any medical condition that in the opinion of the investigators could potentially jeopardize the safety of the patient
5. History of anaphylactic reactions or severe allergies
6. History of allergy to any of the components of OTL38, including folic acid
7. Pregnancy, or positive pregnancy test
8. Clinically significant abnormalities on electrocardiogram (ECG)
9. Presence of any psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule
10. Impaired renal function defined as eGFR< 50 mL/min/1.73m2
11. Impaired liver function defined as values > 3x the upper limit of normal (ULN) for alanine aminotransferase (ALT) or aspartate aminotransferase (AST), alkaline phosphatase (ALP), or total bilirubin.
12. Known Stage IV ovarian cancer with Brain Metastases
13. Received an investigational agent in another investigational drug or vaccine trial within 30 days prior to surgery
14. Known sensitivity to fluorescent light

Number of enrolled subjects

Adverse events were collected from the time of study drug administration throughout the course of the study, ending with Visit 4. The total collection period for each subject was approximately one month.

The definition of AEs and SAEs for this study was consistent with the clinicaltrials.gov definitions.