First-in-human phase 1 study of margetuximab (MGAH22), an Fc-modified chimeric monoclonal antibody, in patients with HER2-positive advanced solid tumors

3013 Background: The release of tumor-associated antigens may enhance the response to immunotherapy. BGB-A317, a humanized IgG4 variant monoclonal antibody engineered to have no Fc gamma receptor binding, targets the programmed cell death-1 (PD-1) receptor. It is being developed in solid and hematologic malignancies at a dose of 200 mg IV Q3W. BGB-290, a potent inhibitor of PARP 1/2, is hypothesized to promote neoantigen release that will potentially increase the efficacy of BGB-A317. A phase 1 study identified 60mg BID as the recommended Phase 2 dose (RP2D) for BGB-290. This study consists of initial dose escalation to determine the maximum-tolerated dose (MTD), safety, PK profile, and preliminary anti-tumor activity of the combination, followed by expansion into ovarian, breast, prostate, gastric, bladder, pancreatic and small cell lung cancers. Methods: Cohorts of 6 -12 pts with advanced solid tumors were treated in each of 5 planned dose levels (DLs). In DLs 1-3, BGB-290 doses ranged between 20-60mg PO BID with BGB-A317 2mg/kg IV Q3W. In DLs 4 - 5, BGB-290 doses were 40 or 60 mg BID; A317 was given at 200 mg IV Q3W based on PK data from a single agent Phase 1 study. Results: As of 16 Jan 2017, 38 pts [median age 59 years (34-75)] were treated in DLs 1-4; enrollment to DL5 is ongoing. One DLT of persistent Gr 2 nausea was reported in DL 4. The most common adverse event (AE) considered related to both study drugs was fatigue (10.5%). Immune-related AEs were Gr 3 hypophysitis (n = 1), Gr 3 or 4 autoimmune hepatitis(n = 2), and Gr 2 elevated AST/ALT (n = 1). Decreases in tumor burden have been observed in 16 pts; 7 achieved a PR (5 with ovarian and one each with uterine and pancreatic cancer) and one CR was observed in ovarian cancer. Six pts had SD for > 6 months including 2 pts with pancreatic cancer who received BGB-A317+BGB-290 for 189 and 281 days. Plasma/serum exposure of BGB-290 and BGB-A317 were consistent with those in single-agent trials. Conclusions: BGB290 and BGB-A317 can be combined. Dose expansion in multiple tumor types is planned to commence in 2017 once the RP2D is determined. Clinical trial information: NCT02660034.

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A phase 1b study of the anti-PD-1 monoclonal antibody BGB-A317 (A317) in combination with the PARP inhibitor BGB-290 (290) in advanced solid tumors.

Journal of Clinical Oncology ◽

10.1200/jco.2018.36.5_suppl.48 ◽

2018 ◽

Vol 36 (5_suppl) ◽

pp. 48-48 ◽

Cited By ~ 7

Author(s):

Michael Friedlander ◽

Tarek Meniawy ◽

Ben Markman ◽

Linda R. Mileshkin ◽

Paul Harnett ◽

...

Keyword(s):

Monoclonal Antibody ◽

Autoimmune Hepatitis ◽

Solid Tumors ◽

Phase 1 ◽

Parp Inhibitor ◽

Single Agent ◽

Maximum Tolerated Dose ◽

Advanced Solid Tumors ◽

Phase 1 Study ◽

Study Results

48 Background: The release of tumor-associated antigens may enhance the response to immunotherapy. BGB-A317, a humanized IgG4 variant monoclonal antibody engineered to have no Fc gamma receptor binding, targets the programmed cell death-1 (PD-1) receptor. It is being developed in solid and hematologic malignancies at a dose of 200 mg IV Q3W. BGB-290, a potent inhibitor of PARP 1/2, is hypothesized to promote neoantigen release that may potentially increase the efficacy of BGB-A317. A phase 1 study identified 60 mg BID as the recommended Phase 2 dose (RP2D) for BGB-290. This study consists of initial dose escalation to determine the maximum-tolerated dose (MTD), safety, pharmacokinetic (PK) profile, and preliminary antitumor activity of the combination, followed by expansion into ovarian, breast, prostate, gastric, bladder, pancreatic and small cell lung cancers. Methods: Cohorts of 6–12 patients with advanced solid tumors were treated in each of 5 planned dose levels (DLs). In DLs 1–3, BGB-290 doses ranged between 20–60 mg PO BID with BGB-A317 2 mg/kg IV Q3W. In DLs 4–5, BGB-290 doses were 40 or 60 mg BID; A317 was given at 200 mg IV Q3W based on PK data from a single agent Phase 1 study. Results: As of 31 March 2017, 43 patients [median age 63 years (34–75)] were treated in DLs 1–5. Three patients experienced four dose-limiting toxicities: grade 2 nausea (DL4), grade 2 nausea and grade 2 vomiting (DL5), and grade 4 autoimmune hepatitis (DL5). MTD was identified as BGB-A317 200 mg IV Q3W + BGB-290 40 mg PO BID. The most common adverse event (AE) considered related to both study drugs was fatigue. Immune-related AEs of Grade ≥3 were elevated alanine aminotransferase/aspartate aminotransferase (n = 3), autoimmune hepatitis (n = 3), and hepatitis (n = 1). Complete or partial response was observed in 11 patients, 4 of whom had confirmed PR or CR. Plasma/serum exposure of BGB-290 and BGB-A317 were consistent with those in single-agent trials. Conclusions: The combination of BGB-A317 and BGB-290 was generally well tolerated in patients with advanced solid tumors. These results support the continuation of this trial with enrollment into the disease-specific cohorts. Clinical trial information: NCT02660034.

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