Abstract 2569
Background
MEK inhibition may overcome resistance to EGFR inhibition alone in patients (pts) with RAS wt mCRC. We evaluated the antitumor activity of T (MEK1/2 inhibitor) with Pmab (EGFR monoclonal antibody) in a phase II trial.
Methods
Pts with KRAS, NRAS, and BRAF wt mCRC with prior 5-FU, irinotecan, oxaliplatin, +/- bevacizumab and no prior EGFR therapy were treated with T 1.5mg oral daily and Pmab 4.8mg/kg IV every 2 weeks. Primary endpoint was clinical benefit (CB; CR, PR or SD ≥ 24 weeks) by RECIST v1.1. A 2-stage minimax design (p0=0.20, p1=0.45, 1-sided alpha=0.05, power=0.85) required ≥4/13 patients with CB in stage I and ≥8/26 patients with CB by end of stage II. Response assessments were performed every 4 cycles (C). Adverse events (AEs) were assessed by CTCAE v4.03. Tumor biopsies were performed before C1 and during C2. Plasma circulating free DNA (cfDNA) collected before C1, C2, C3 and every 2 subsequent C and were profiled using the Oncomine Lung cfDNA assay.
Results
There were 13 pts enrolled from Nov2015 to Dec2018. Of 12 evaluable patients, best response was confirmed PR (n = 3), unconfirmed PR (n = 5), and SD (n = 4) (unconfirmed ORR 67%). Two patients achieved CB ≥ 24 weeks (2/10; 20%) and two patients are still on trial with PR not yet evaluable for CB. The most common treatment-related AE (trAE) was acneiform rash (85%) including 31% with grade 3. Other trAEs were diarrhea (62%), mucositis (46%), maculopapular rash (54%), and vomiting (31%). Dose modifications and interruptions of T occurred in 69% of patients and 54% of patients receiving Pmab had dose modifications. Median PFS is 4.4 months (95% CI 2.9-7.1). Of 3 pts with serial cfDNA profiling results available, none had KRAS, NRAS, or BRAF mutations detectable before treatment, and 1 patient demonstrated polyclonal KRAS, NRAS, and BRAF mutations at C5 before radiographic progression at C9.
Conclusions
The addition of T to Pmab leads to a high rate of tumor shrinkage in RAS/RAF wt mCRC. Median PFS is similar to Pmab alone in the ASPECCT trial, which may be due to a high incidence of skin toxicity with the combination that leads to dose interruption and/or reduction. Additional results from cfDNA and tumor biopsies will be presented.
Clinical trial identification
NCT02399943.
Editorial acknowledgement
Legal entity responsible for the study
Philippe Bedard.
Funding
Conquer cancer foundation of ASCO career development (Dr P. Bedard), Canadian Cancer Research Society Institute innovation grant (Dr P. Bedard), and drug supply from GlaxoSmithKline and Novartis.
Disclosure
A.R.R. Albiruni: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Boehringer Ingelheim; Advisory / Consultancy, Research grant / Funding (institution): Lilly; Advisory / Consultancy, Research grant / Funding (institution): Merck; Research grant / Funding (institution): CASI Pharmaceuticals; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Deciphera; Research grant / Funding (institution): Karyopharm Therapeutics; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Genentech/ Roche; Research grant / Funding (institution): Boston Biomedical; Research grant / Funding (institution): Bristol-Myers Squibb; Research grant / Funding (institution): MedImmune; Research grant / Funding (institution): Amgen; Research grant / Funding (institution): GlaxoSmithKline; Research grant / Funding (institution): Blueprint Medicines; Research grant / Funding (institution): AbbVie; Research grant / Funding (institution): Adaptimmune. A. Spreafico: Advisory / Consultancy, Research grant / Funding (institution): Merck; Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy: Oncorus; Research grant / Funding (institution): Symphogen AstraZeneca / Medimmune; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): Surface Oncology; Research grant / Funding (institution): Northern Biologics; Research grant / Funding (institution): Janssen Oncology/ Johnson & Johnson. A.R. Hansen: Advisory / Consultancy, Research grant / Funding (institution): Genentech/ Roche; Advisory / Consultancy, Research grant / Funding (institution): Merck; Advisory / Consultancy, Research grant / Funding (institution): GlaxoSmithKline; Advisory / Consultancy, Research grant / Funding (institution): Bristol-Myers Squibb; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy, Research grant / Funding (institution): Boston Biomedical; Advisory / Consultancy, Research grant / Funding (institution): Boehringer-Ingelheim; Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca; Advisory / Consultancy, Research grant / Funding (institution): Medimmune. L.L. Siu: Advisory / Consultancy, Research grant / Funding (institution): Merck; Advisory / Consultancy, Research grant / Funding (institution): Pfizer; Advisory / Consultancy, Research grant / Funding (institution): Celgene; Advisory / Consultancy, Research grant / Funding (institution): AstraZeneca/ MedImmune; Advisory / Consultancy: Morphosys; Advisory / Consultancy: Roche; Advisory / Consultancy: GeneSeeq; Advisory / Consultancy: Loxo; Advisory / Consultancy: Oncorus; Advisory / Consultancy: Symphogen; Advisory / Consultancy: Seattle Genetics; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Bristol-Myers Squibb; Research grant / Funding (institution): Boehringer Ingelheim; Research grant / Funding (institution): GlaxoSmithKline; Research grant / Funding (institution): Genentech/Roche; Research grant / Funding (institution): Karyopharm; Research grant / Funding (institution): Astellas; Research grant / Funding (institution): Bayer; Research grant / Funding (institution): AbbVie. P. Bedard: Research grant / Funding (institution): Bristol-Myers Squibb; Research grant / Funding (institution): Sanofi; Research grant / Funding (institution): AstraZeneca; Research grant / Funding (institution): Genentech/Roche; Research grant / Funding (institution): SERVIER; Research grant / Funding (institution): GlaxoSmithKline; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): SignalChem; Research grant / Funding (institution): PTC Therapeutics; Research grant / Funding (institution): Nektar; Research grant / Funding (institution): Merck; Research grant / Funding (institution): Seattle Genetics; Research grant / Funding (institution): Mersana; Research grant / Funding (institution): Immunomedics; Research grant / Funding (institution): Lilly. All other authors have declared no conflicts of interest.
Resources from the same session
3266 - Morphology of tumor-associated macrophages dictates the prognosis of patients with colorectal liver metastases.
Presenter: Matteo Donadon
Session: Poster Display session 2
Resources:
Abstract
1694 - Pembrolizumab (pembro) Plus mFOLFOX or FOLFIRI in Patients With Metastatic Colorectal Cancer (mCRC): KEYNOTE-651 Cohorts B and D
Presenter: Richard Kim
Session: Poster Display session 2
Resources:
Abstract
908 - Romidepsin (FK228) Regulates the Expression of the Immune Checkpoint Ligand PD-L1 and Exerts Synergistic Anti-Tumor Activity with an Anti-PD-1 Antibody in Colon Cancer
Presenter: Hui Li
Session: Poster Display session 2
Resources:
Abstract
3127 - Prognostic significance of circulating regulatory T lymphocytes (Tregs) in patients with metastatic colorectal cancer (mCRC) under treatment with first line chemotherapy.
Presenter: Zafeiris Zafeiriou
Session: Poster Display session 2
Resources:
Abstract
5416 - The SAFFO study: Sex-related prognostic role And cut-oFf deFinition of monocyte-to-lymphocyte ratio (MLR) in metastatic colOrectal cancer
Presenter: Camilla Lisanti
Session: Poster Display session 2
Resources:
Abstract
2518 - SPICE, a phase I study of enadenotucirev in combination with nivolumab in tumors of epithelial origin: analysis of the metastatic colorectal cancer patients in the dose escalation phase
Presenter: Marwan Fakih
Session: Poster Display session 2
Resources:
Abstract
4000 - Phase 1/2 study with CXCL12 inhibitor NOX-A12 and pembrolizumab in patients with microsatellite-stable, metastatic colorectal or pancreatic cancer
Presenter: Niels Halama
Session: Poster Display session 2
Resources:
Abstract
2223 - Microsatellite Instability Status in Metastatic Colorectal Cancer and Effect of Immune Checkpoint Inhibitors on Survival in MSI-High Metastatic Colorectal Cancer
Presenter: Wataru Okamoto
Session: Poster Display session 2
Resources:
Abstract
5402 - Microsatellite instability and immunogenicity in colorectal cancer – do resident memory Tcells (Trm) play a role in colorectal cancer
Presenter: Wei Toh
Session: Poster Display session 2
Resources:
Abstract
5472 - Early response evaluation and CEA response in patients treated in a Danish randomized study comparing trifluridine/tipiracil (TAS-102) with or without bevazicumab in patients with chemorefractory metastatic colorectal cancer (mCRC)
Presenter: Camilla Qvortrup
Session: Poster Display session 2
Resources:
Abstract