Cabiralizumab

A DLT was defined as a study drug-related ≥ Grade 3 AE (using National Cancer Institute Common Terminology Criteria for Adverse Events v 4.03) occurring during the first 28-days, excluding Grade 3 tumor flare (defined as local pain, irritation, or rash localized at sites of known or suspected tumor), rash, immune-related adverse event (irAE) that resolved to ≤ Grade 1 by 14 days or a transient (resolving within 6 hours of onset) Grade 3 infusion-related AE. Any recurrence of Grade 3 rash, irAE or infusion-related AE was considered a DLT. The protocol was amended such that in the absence of clinical symptoms and other accompanying changes in bilirubin or alanine aminotransferase (ALT), serum elevation of aspartate aminotransferase (AST)/ALT \> 12 × upper limit of normal (ULN) and ≤ 20 × ULN that lasted for \< 7 days and serum elevation of creatine kinase (CK) and/or lactate dehydrogenase (LDH) \> 15 × ULN and ≤ 20 × ULN that lasted for \< 7 days were not considered DLTs.

Using both the incidence of dose limiting toxicities (first 28 days on therapy) as well as overall tolerability and toxicities observed beyond 28 days, the RD was chosen as 4 mg/kg of cabiralizumab + 3 mg/kg nivolumab every 2 weeks to be the dose used in the Phase 1b (dose expansion). No maximum tolerated dose was identified.

An AE is defined as any new untoward medical occurrence or worsening of a preexisting medical condition in a clinical investigation, patient-administered study drug and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (such as an abnormal laboratory finding), symptom, or disease temporally associated with the use of study drug, whether or not considered related to the study drug. A Serious Adverse Event (SAE) is any untoward medical occurrence that at any dose: * Resulted in death; * Was life-threatening; * Required inpatient hospitalization or causes prolongation of existing hospitalization; * Resulted in persistent or significant disability/incapacity; * Was a congenital anomaly/birth defect; * Was an important medical event that may jeopardize the patient or may require intervention (e.g., medical, surgical) to prevent one of the other serious outcomes listed in the definition above.

Safety: In the Phase 1b only, the incidence of treatment discontinuations, modifications, and interruptions due to adverse events.

Objective response rate (ORR) is defined as the percentage of participants with confirmed responses of either complete response (CR) or partial response (PR). Response was evaluated using Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1 by investigator review. Complete Response: Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to \<10 mm. Partial Response: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.