A Study of the c-Kit Specific Antibody-Drug Conjugate NN3201 for Advanced and/or Metastatic Solid Tumors Known to Express c-Kit

Key Inclusion Criteria:

Subjects must meet the following criteria to be eligible for enrollment into the study:

1. Histologically or cytologically confirmed locally advanced, metastatic, and/orunresectable GIST, SCLC, ACC, uveal melanoma, NET ChRCC or ccRCC.

2. Subjects must have received the following treatment: Part A (Dose Escalation): i. Treatment with imatinib for GIST (at least one line of therapy with imatinib) or ii. Progressive/refractory, ineligible, or intolerant to available standard therapy (or subject declines standard therapy) for c-Kit-associated solid tumors (ACC, uvealmelanoma, NET ChRCC or ccRCC) Part B (Dose Expansion): i. Treatment with imatinib for GIST (at least one line of therapy with imatinib) or ii. Progressive/refractory, ineligible, or intolerant to available standard therapy (or subject declines standard therapy) for Extensive stage SCLC or iii. Progressive/refractory, ineligible, or intolerant to available standard therapy (or subject declines standard therapy) for c-Kit-associated solid tumors (ACC, uvealmelanoma, NET or ChRCC or ccRCC).

3. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

4. Life expectancy ≥ 3 months before starting NN3201 in the opinion of theInvestigator.

5. Age ≥ 18 years.

6. Laboratory values demonstrating adequately functioning kidney, liver and bone marrow (hematology).

7. Adequate heart function as measured by ECHO/MUGA scan.

8. Time between prior anticancer therapy including investigational agents and firstdose of NN3201 as below:

9. Cytotoxic chemotherapy - At least 21 days

10. Non-cytotoxic chemotherapy (e.g., small molecule inhibitor) - At least 14 days

11. Nitrosoureas - At least 6 weeks

12. Monoclonal antibody(ies) - At least 28 days

13. Radiotherapy - At least 14 days from local site radiation therapy

14. Negative Serum/urine pregnancy test (for subjects of childbearing potential)

15. All subjects of childbearing potential must agree to use contraception throughoutthe study and for additional 120 days after the last dose of assigned treatment.Subjects must refrain from donating sperm during the same period or Subjects who donot have childbearing potential are confirmed post-menopausal or sterile.

16. Voluntary agreement to provide written informed consent and have willingness andability to comply with all aspects of the protocol.

Key Exclusion Criteria:

1. Has received prior therapy with a c-Kit agent (except GIST subjects).

2. Known brain metastases that are untreated, symptomatic, or require therapy tocontrol symptoms.

3. A condition requiring systemic treatment with corticosteroids (>10 mg dailyprednisone equivalent) or other immunosuppressive medications within 14 days priorto administration of study drugs (inhaled corticosteroids are allowed).

4. Any prior treatment-related (i.e., chemotherapy, immunotherapy, radiotherapy)clinically significant toxicities that have not resolved to Grade ≤ 1 or priortreatment-related toxicities that are clinically unstable and clinically significantat Study Entry, Day -2 to Cycle 1 Day 1.

5. Major surgery within 30 days before the first dose of study drug treatment in Cycle 1 on Day 1 (port placement for venous access is not considered major surgery).

6. Significant cardiovascular impairment.

7. Significant screening electrocardiogram (ECG) abnormalities.

8. Known active and clinically significant bacterial, fungal, or viral infection.

9. Uncontrolled hypertension defined as systolic blood pressure ≥ 160mmHg and/ordiastolic blood pressure ≥ 100mmHg, despite optimal medical management.

10. Venous thrombosis or pulmonary embolism within the last 3 months prior to thescreening.

11. Ongoing or active infection requiring intravenous treatment with anti-infectivetherapy or systemic therapy and/or any identified active COVID-19 infection.

12. Any other major illness that, in the Investigator's judgment, will substantiallyincrease the risk associated with the subject's participation in this study.

13. People who are pregnant or breastfeeding.

Other inclusion and exclusion criteria must also be met to be eligible to participate in this study.