A Study to Investigate Safety and Effectiveness of CRN09682 in Participants With SST2-Expressing NENs and Other Solid Tumors

(Dose Escalation) Maximum Plasma Concentration (Cmax) of CRN09682 and MMAE .

Time frame: Day 1 of each cycle (each cycle is 21 days) for the duration of the study, from baseline to safety follow-up visit, up to 2 years.

(Dose Escalation) Time to Maximum Concentration (Tmax) of CRN09682 and MMAE.

Time frame: Day 1 of each cycle (each cycle is 21 days) for the duration of the study, from baseline to safety follow-up visit, up to 2 years.

(Dose Escalation) Measure of CRN09682 and MMAE exposure in the body from initial dose to the last measurable concentration (AUC0-last).

Time frame: Day 1 of each cycle (each cycle is 21 days) for the duration of the study, from baseline to safety follow-up visit, up to 2 years.

(Dose Escalation) Measure of total CRN09682 exposure in the body across time (AUC0-inf).

Time frame: Day 1 of each cycle (each cycle is 21 days) for the duration of the study, from baseline to safety follow-up visit, up to 2 years.

(Dose Escalation) The amount of time required for CRN09682 to be reduced to half of its initial concentration in the blood (t1/2).

Time frame: Day 1 of each cycle (each cycle is 21 days) for the duration of the study, from baseline to safety follow-up visit, up to 2 years.

(Dose Escalation & Expansion) Objective response rate (ORR): The percentage of patients with best overall response of complete response or partial response according to RECIST 1.1

Time frame: Throughout the study until disease progression or the last evaluable assessment in the absence of progression whichever occurs first, approximately 2 years.

(Dose Escalation & Expansion) Disease control rate (DCR): The percentage of patients with best overall response of complete response, partial response, or stable disease according to RECIST 1.1

Time frame: Throughout the study until disease progression or the last evaluable assessment in the absence of progression whichever occurs first , approximately 2 years.

(Dose Escalation & Expansion) Duration of response (DOR): The time from the date of first objective response until date of disease progression or death in the absence of disease progression, according to RECIST 1.1.

Time frame: From the first documented objective response to disease progression or death whichever occurs first, approximately 2 years.

(Dose Expansion) Changes in somatostatin receptor imaging: Evaluate changes in SSR tracer uptake over time, based on whether uptake is greater than or less than liver uptake.

Time frame: Throughout the study at predefined intervals, approximately 2 years.

(Dose Expansion) Radiographic PFS: The time from the start of study drug until RECIST 1.1 defined disease progression or death in the absence of disease progression.

Time frame: Throughout the study until disease progression or death whichever occurs first, approximately 2 years.