Safety and Tolerability of ²¹²Pb-DOTAM-GRPR1 in Adult Subjects With Recurrent or Metastatic GRPR-expressing Tumors

Inclusion Criteria:

Male or female ≥18 years old with the following histologically confirmed metastatic or recurrent GRPR-expressing tumors:

Metastatic castrate resistant prostate cancer (mCRPC);
HR+/HER2- breast cancer;
Colorectal cancer;
Cervical cancer;
Cutaneous melanoma;
Non-small-cell lung cancer (NSCLC).

Biopsies must demonstrate the following on immunohistochemistry (IHC):

51-80% positively staining cells; and
Moderate intensity of staining.
Subjects with recurrent disease must have progressed on at least 2 prior systemic therapies.
Presence of at least 1 site of measurable disease per RECIST 1.1 within 1 month prior to Cycle 1 Day 1. For subjects with prostate cancer, bone lesions may be used to fulfill the eligibility requirements per PCWG3 in lieu of measurable disease per RECIST 1.1.
Eastern Cooperative Oncology Group (ECOG) status 0-2.

Sufficient bone marrow capacity and organ function as defined by:

White blood cell (WBC) ≥2,500/ mm³
Absolute neutrophil count (ANC) ≥1500/mm³
Platelets ≥75,000/mm³
Hemoglobin (HgB) ≥9.0 g/dL;

Exclusion Criteria:

Previous whole-body radiotherapy or peptide receptor radionuclide therapy (PRRT) with either alpha or beta emitters, or subjects with mCRPC who have received radium-223 (²²³Ra).
Known hypersensitivity to any component of ²¹²Pb-DOTAM-GRPR1.
Exposure to any other GRPR-targeting therapeutic agents.
History of chronic pancreatitis
History of pneumonitis.

Impaired cardiac function defined as:

New York Heart Association (NYHA) class III or IV;
QTc > 470 msec for females and QTc >450 msec for males on screening electrocardiogram (ECG) or congenital long QT syndrome;
Acute myocardial infarction or unstable angina pectoris < 3 months prior to study enrollment.
Cyclical chemotherapy, radiotherapy, or biologic therapy (e.g. antibodies), continuous or intermittent, small molecule therapeutics, or any investigational agents within a period which is ≤ 5 half-lives or ≤ 4 weeks (whichever is longer) prior to Day 1.