Nipavect: Phase II study of niraparib and panitumumab in advanced RAS WT colorectal cancer.

Authors

null

Olatunji B. Alese

Winship Cancer Institute of Emory University, Atlanta, GA

Olatunji B. Alese , Maria Diab , Olumide B. Gbolahan , Ashley McCook-Veal , Walid Labib Shaib , Christina Wu , Mehmet Akce , Yuan Liu , Gregory B. Lesinski , Bassel F. El-Rayes

Organizations

Winship Cancer Institute of Emory University, Atlanta, GA, Emory University, Atlanta, GA, Emory University School of Medicine, Atlanta, GA, Winship Cancer Institute, Grayson, GA, Emory University Winship Cancer Institute, Atlanta, GA, Mayo Clinic, Phoenix, AZ, Division of Hematology/Oncology, University of Alabama at Birmingham, Birmingham, AL, Birmingham, AL, Departments of Biostatistics and Bioinformatics, Emory University, Atlanta, GA, Winship Cancer Institute of Emory Univeristy, Atlanta, GA, The University of Alabama at Birmingham, Birmingham, AL

Research Funding

Pharmaceutical/Biotech Company
GSK

Background: Panitumumab (Pmab) is a recombinant monoclonal antibody that binds specifically to the human epidermal growth factor receptor (EGFR) and it is indicated for the treatment of metastatic colorectal carcinoma (mCRC). However, the objective response rates (ORR) for the single agent are historically about 8-11%. EGFR inhibition induces synthetic lethality with poly ADP ribose polymerase inhibitors (PARPi) such as Niraparib, by attenuating DNA repair pathways. Combining PARP and EGFR inhibition has the potential to confer synergistic benefit, while also ameliorating resistance mechanism to EGFRi. We conducted this study to define the safety and efficacy of the combination of Niraparib and Pmab in RAS wildtype (WT) mCRC. Methods: Patients (pts) with RAS WT mCRC who have progressed on at least one line of systemic chemotherapy were eligible for the trial. Other selected inclusion criteria were ≥18 years of age, ECOG PS 0-1 and measurable disease per RECIST 1.1. Pmab was administered at 6 mg/kg IV on days 1 & 15 of each 28-day cycle, while Niraparib was taken orally at 200mg or 300mg (based on body weight and platelet count) daily throughout the cycle. The primary endpoint was clinical benefit rate (CBR) defined as complete (CR) + partial (PR) response + stable disease (SD) per RECIST v1.1. Multiple secondary endpoints included safety/tolerability, ORR, progression-free survival (PFS), overall survival (OS), and duration of response (DoR). Results: A safety run-in cohort of 6 pts was initially enrolled. Following a preplanned safety analysis showing an acceptable toxicity profile, an additional 19 pts were enrolled. Of the total 25 enrolled pts, 24 were evaluable for response. Male - 50%; Whites/African Americans/Asians – 65.2%/21.7%/13%; median age – 58.5yrs. The majority had left sided tumor (92%) and the median line of prior therapy was 2 (range 1-4). CBR was 83.3% (0 CR, 6 PR, 14 SD) and ORR was 25%. mPFS – 5.6mos (95% CI: 3.7, 6.9); mOS – 20.9mos (95% CI: 9.2, NR). Six-month PFS and OS rates were 48.4% and 100% respectively. At a median follow up time of 7.5mos (95% CI: 4.2, 10.4), 3 patients remained on treatment and DoR was yet to be determined. Muco-cutaneous adverse events (AEs) of any grade included rash (58.4%), oral mucositis (20.8%), dry skin (16.7%) and paronychia (4.2%). Most common (grade > 2) treatment related AEs (TRAEs) were anemia (G3; 12.5%), dermatitis, oral mucositis, hypertension and neutropenia (G3; 4.2% each). There were no grade 4-5 TRAEs. Conclusions: The combination of Pmab and Niraparib had an acceptable safety profile, and showed considerable antitumor activity in pts with advanced RAS WT mCRC compared to historical rates. Additional biomarker analyses such as survival correlation with immune cell infiltration in paired skin biopsies and HER2/BRAF mutational status are ongoing. Funding and product (Niraparib) for the study were provided by GSK (NCT03983993). Clinical trial information: NCT03983993.

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Abstract Details

Meeting

2023 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Gastrointestinal Cancer—Colorectal and Anal

Track

Gastrointestinal Cancer—Colorectal and Anal

Sub Track

Colorectal Cancer–Advanced Disease

Clinical Trial Registration Number

NCT03983993

Citation

J Clin Oncol 41, 2023 (suppl 16; abstr 3579)

DOI

10.1200/JCO.2023.41.16_suppl.3579

Abstract #

3579

Poster Bd #

279

Abstract Disclosures