Nivolumab is approved by the FDA for the treatment of melanoma, non-small cell lung cancer (NSCLC), malignant pleural mesothelioma, renal cell carcinoma, classical Hodgkin lymphoma, squamous cell carcinoma of head/neck, urothelial carcinoma, MSI-H colorectal cancer, hepatocellular carcinoma, gastric carcinoma and gastroesophageal junction (GEJ) cancer.~Pixatimod is an investigational drug that activates the toll-like receptor 9 (TLR9) pathway and is being evaluated in studies involving melanoma, non-small cell lung cancer, and microsatellite stable colorectal cancer.~Cyclophosphamide is approved by the FDA for the treatment of acute lymphoblastic leukemia, acute monocytic leukemia, acute myeloid leukemia, breast cancer, chronic granulocytic leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, Hodgkin lymphoma, multiple myeloma, mycosis fungoides, neuroblastoma, non-Hodgkin lymphoma, ovarian cancer, retinoblastoma. Low-dose (immunomodulatory) cyclophosphamide is being studied in combination with various types of immunotherapy including nivolumab and pembrolizumab.~This Phase llA trial hypothesizes that the nivolumab/pixatimod combination in PD-1 relapsed/refractory (R/R) cutaneous melanoma and NSCLC patients will be associated with anti-tumor effects, and that the nivolumab/pixatimod/cyclophosphamide combination in MSS mCRC patients will be associated with anti-tumor effect.~In the 1st stage, 13 patients will be enrolled in cohort 1 while 9 patients each will be enrolled in cohorts 2 and 3. Should the pre-specified efficacy boundary met, further patients will be enrolled to one or more cohorts in 2nd stage. The total enrollment for 1st stage across all 3 cohorts is 31 response-evaluable patients. The total enrollment for both stages across all 3 cohorts is 61 response-evaluable patients.
The primary goal of this trial is to assess clinical response to nivolumab and pixatimod, and, nivolumab, pixatimod and cyclophosphamide in three separate patient cohorts. Cohort 1: MSS mCRC in combination with low-dose cyclophosphamide, Cohort 2: PD-1 relapsed/refractory melanoma, and Cohort 3: PD-1 relapsed/refractory NSCLC.