Study of Magrolimab (Hu5F9-G4) in Combination With Avelumab in Solid Tumor Participants and Checkpoint-Inhibitor-Naive Ovarian Cancer Participants Who Progress Within 6 Months of Prior Platinum Chemotherapy

A DLT was defined as a ≥ Grade 3 AE that was assessed as related to either magrolimab or avelumab that occurred during the 5-week DLT assessment period with protocol-defined allowed exceptions. Any treatment-emergent adverse event (TEAE) that was, in the opinion of the Clinical Trial Steering Committee, of potential clinical significance such that further dosing exposed participants to unacceptable risk, was considered a DLT.

An AE was any unfavorable and unintended sign, symptom, or disease temporally associated with the use of an investigational product or other protocol-imposed intervention, regardless of attribution. Treatment-emergent AEs were defined as those AEs that worsened or occurred during or after a participant's first dose of any study treatment and those existing AEs that worsened during the study and within 30 days after the last administration of any study treatment or initiation of subsequent anticancer therapy, whichever occurred first.

Objective response was defined as the percentage of participants with objective response which consisted of complete response (CR)+ partial response (PR) determined by RECIST v 1.1. CR: Disappearance of all target and all non-target lesions and normalization of tumor marker level. All lymph nodes must be non-pathological in size (< 10 mm short axis). Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to < 10 mm. PR: At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.

The RP2DS was the dose of magrolimab in combination with avelumab with DLT rate less than 33% in at least 6 evaluable participants in Part 1. A DLT was defined as a ≥ Grade 3 AE that was assessed as related to either magrolimab or avelumab that occurred during the 5-week DLT assessment period with protocol-defined allowed exceptions. Any TEAE that was, in the opinion of the Clinical Trial Steering Committee, of potential clinical significance such that further dosing exposed participants to unacceptable risk, was considered a DLT.

Serum concentrations will be drawn at pre-study drug infusion (within 12 hours) on Day (D) 1 and 22 in Cycle (C) 1; Days 1 and 15 in Cycle 2; Day 1 in Cycles 3 and 4; every 3rd cycle on Day 1 until Cycle 13; 1 hour post-magrolimab infusion on Days 1 and 8 in Cycle 1; 24 hours post magrolimab infusion (Part 1 only) on Days 1 and 8 in Cycle 1; pre-study drug infusion on Day 1 in Cycles 5 and 11 (Part 1 Magrolimab 45 mg/kg only); End of Treatment (EOT) visit (up to Cycle 13); Safety Follow-up Visit (30 days after last dose of magrolimab, maximum treatment duration 18.3 months). Cycle 1 consisted of 35 days and Cycle 2 and subsequent cycle consisted of 28 days.

Objective response was defined as participants with a CR or a PR as assessed per GCIG criteria. The GCIG proposed use of both the RECIST and cancer antigen 125 (CA-125) criteria. A response according to CA-125 has occurred if there is ≥ 50% reduction in CA-125 levels from a pretreatment sample. The response had to be confirmed and maintained for at least 28 days. Participants can be evaluated according to CA-125 only if they had a pretreatment sample that was at least twice the upper limit of normal (ULN) and within 2 weeks prior to starting treatment. According to RECIST 1.1, CR was defined as disappearance of all target and all non-target lesions and normalization of tumor marker level. All lymph nodes must be non-pathological in size (< 10 mm short axis). Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to < 10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference baseline sum diameters.

DOR: time from initial response (CR or PR) until disease progression. Disease progression was defined according to RECIST 1.1 but can also be based on serum CA-125. Progression based on serum CA-125 levels was defined as (1) elevated CA-125 pretreatment and normalization of CA-125 with evidence of CA-125 ≥2x ULN on 2 occasions at least 1 week apart or; (2) elevated CA-125 pretreatment, which never normalizes, with evidence of CA-125 ≥2x nadir value on 2 occasions at least 1 week apart or; (3) CA-125 in normal range pretreatment with evidence of CA-125 ≥2x ULN on 2 occasions at least 1 week apart.

Progression per RECIST 1.1: At least a 20% increase in sum of diameters of target lesions, taking as reference smallest sum measured while on study (this included baseline sum if that was smallest). In addition to relative increase of 20%, sum must also demonstrate absolute increase of at least 5 mm. Unequivocal progression of existing non-target lesion.

PFS was defined as the duration of time from dose initiation to the first date of objectively documented disease progression per RECIST 1.1 or death, whichever occurred at first. Progression as per RECIST 1.1: At least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum measured while on study (this included the baseline sum if that was the smallest on study). In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. Unequivocal progression of existing non-target lesions. Participants who did not have documented disease progression and did not die were censored at their last tumor assessment date. Kaplan-Meier estimate was used for analysis

OS was defined as the duration of time from dose initiation to the date of death due to any cause. Participants who did not die were censored at their last known alive date.

Kaplan-Meier estimate was used for analysis.

Paired tumor biopsies from participants with ovarian cancer were analyzed by CD68 immunohistochemistry staining to evaluate the impact of magrolimab in combination with avelumab on macrophage frequency in the tumor microenvironment.