A Phase 1b/2 Study of the Anti-CD47 Antibody Magrolimab with Cetuximab in Patients with Colorectal Cancer and Other Solid Tumors.

BACKGROUND

Chemotherapy plus epidermal growth factor receptor (EGFR) inhibitors, such as cetuximab, is standard therapy for KRAS wild-type (KRASwt) colorectal cancer (CRC); however, responses are infrequent. Magrolimab is a monoclonal antibody targeting CD47, an antiphagocytic signal overexpressed in solid tumors (STs).

OBJECTIVE

This open-label, multicenter phase 1b/2 study (NCT02953782) aimed to determine the recommended phase 2 dose (RP2D) and evaluate the safety, tolerability, and efficacy of magrolimab + cetuximab in patients with advanced CRC or other STs.

PATIENTS AND METHODS

A total of 78 patients were enrolled at eight study sites in the USA. In phase 1b, patients with advanced STs received weekly maintenance doses of magrolimab at 10-45 mg/kg and cetuximab at 200-250 mg/m following 3 + 3 dose-escalation. In phase 2, patients with anti-EGFR-refractory CRC received magrolimab + cetuximab at RP2Ds. Primary endpoints were dose-limiting toxicities, adverse events, and objective response rate (ORR; phase 2).

RESULTS

The maximum tolerated dose was not reached in phase 1b. Two RP2Ds were explored in phase 2: magrolimab at 30 or 45 mg/kg plus cetuximab at 250 mg/m. Most common treatment-related adverse events (TRAEs) were dermatitis acneiform (35.9%), infusion-related reactions (33.3%), dry skin (32.1%), fatigue (32.1%), and headache (29.5%). Most common grade ≥ 3 TRAEs were anemia (11.5%), increased blood bilirubin (9.0%), and decreased lymphocyte count (9.0%). Discontinuation of any study treatment owing to TRAEs occurred in 3.8% of patients. No deaths occurred due to TRAEs. In phase 2, ORR was 6.3% and 0% in the KRASwt and KRASmt CRC cohorts, respectively; disease control rate was 50.0% and 38.1%, and median overall survival was 9.5 and 7.6 months, respectively.

CONCLUSIONS

These results indicate tolerability and potential antitumor activity when combining anti-CD47 therapy and cetuximab in heavily pretreated patients with CRC.