A. Varga

Abstract S5-07: Preliminary efficacy and safety of pembrolizumab (MK-3475) in patients with PD-L1–positive, estrogen receptor-positive (ER+)/HER2-negative advanced breast cancer enrolled in KEYNOTE-028

Background: The programmed cell death 1 (PD-1) pathway is used by tumors to evade immune surveillance. Pembrolizumab is a humanized anti–PD-1 monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2. Pembrolizumab has shown robust antitumor activity against several advanced malignancies, including triple-negative breast cancer. We assessed the safety and efficacy of pembrolizumab in patients with PD-L1–positive, ER+/HER2-negative advanced breast cancer. Methods: KEYNOTE-028 (ClinicalTrials.gov, NCT02054806) is an ongoing multicohort, open-label phase 1b study evaluating the safety and efficacy of pembrolizumab in patients with PD-L1–positive advanced solid tumors. Key eligibility criteria for this cohort include ER+ and HER2-negative tumor status defined by institutional standards, locally advanced or metastatic disease, ECOG performance status of 0 or 1, failure of or inability to receive standard therapy, and PD-L1 expression in stroma or in ≥1% of tumor cells as assessed at a central laboratory using a prototype immunohistochemistry assay with the 22C3 antibody (Merck). Pembrolizumab was administered at a dose of 10 mg/kg every 2 weeks for up to 24 months or until confirmed progression or intolerable toxicity. Response is based on RECIST v1.1 as assessed by investigator review every 8 weeks for the first 6 months and every 12 weeks thereafter. Primary efficacy end point is overall response rate (ORR). Results: Of the 248 patients with ER+/HER2-negative breast cancer who had evaluable tumor samples screened for PD-L1 expression, 48 (19%) had PD-L1–positive tumors. Of these, 25 patients were enrolled. Median age was 53 years (range, 36-79), and 44% of patients had an ECOG performance status of 1. Patients were heavily pretreated, with 76% having received ≥3 prior lines of therapy for advanced disease, including 48.0% who received ≥5 prior lines. Analyses of ORR, duration of response, and adverse events are ongoing and will be completed by September 4, 2015. Conclusion: Data from this KEYNOTE-028 cohort will provide information on the antitumor activity and safety of pembrolizumab in patients with heavily pretreated, PD-L1–positive, ER+/HER2-negative advanced breast cancer. Citation Format: Rugo HS, Delord J-P, Im S-A, Ott PA, Piha-Paul SA, Bedard PL, Sachdev J, Le Tourneau C, van Brummelen E, Varga A, Saraf S, Pietrangelo D, Karantza V, Tan A. Preliminary efficacy and safety of pembrolizumab (MK-3475) in patients with PD-L1–positive, estrogen receptor-positive (ER+)/HER2-negative advanced breast cancer enrolled in KEYNOTE-028. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S5-07.

First-in-Human Phase I Study of Single-agent Vanucizumab, A First-in-Class Bispecific Anti-Angiopoietin-2/Anti-VEGF-A Antibody, in Adult Patients with Advanced Solid Tumors

Purpose: Vanucizumab is an investigational antiangiogenic, first-in-class, bispecific mAb targeting VEGF-A and angiopoietin-2 (Ang-2). This first-in-human study evaluated the safety, pharmacokinetics, pharmacodynamics, and antitumor activity of vanucizumab in adults with advanced solid tumors refractory to standard therapies. Experimental Design: Patients received escalating biweekly (3–30 mg/kg) or weekly (10–30 mg/kg) intravenous doses guided by a Bayesian logistic regression model with overdose control. Results: Forty-two patients were treated. One dose-limiting toxicity, a fatal pulmonary hemorrhage from a large centrally located mediastinal mass judged possibly related to vanucizumab, occurred with the 19 mg/kg biweekly dose. Arterial hypertension (59.5%), asthenia (42.9%), and headache (31%) were the most common toxicities. Seventeen (41%) patients experienced treatment-related grade ≥3 toxicities. Toxicity was generally higher with weekly than biweekly dosing. A MTD of vanucizumab was not reached in either schedule. Pharmacokinetics were dose-linear with an elimination half-life of 6–9 days. All patients had reduced plasma levels of free VEGF-A and Ang-2; most had reductions in KTRANS (measured by dynamic contrast-enhanced MRI). Two patients (renal cell and colon cancer) treated with 30 mg/kg achieved confirmed partial responses. Ten patients were without disease progression for ≥6 months. A flat-fixed 2,000 mg biweekly dose (phamacokinetically equivalent to 30 mg/kg biweekly) was recommended for further investigation. Conclusions: Biweekly vanucizumab had an acceptable safety and tolerability profile consistent with single-agent use of selective inhibitors of the VEGF-A and Ang/Tie2 pathway. Vanucizumab modulated its angiogenic targets, impacted tumor vascularity, and demonstrated encouraging antitumor activity in this heterogeneous population. Clin Cancer Res; 24(7); 1536–45. ©2017 AACR.

Mise au point sur l’inhibition de la voie Ras-MAPK : les inhibiteurs de MekFocus on targeting the Ras-MAPK pathway: the Mek inhibitors

The Ras/Raf/Mek/Erk pathway is a key component of tumor progression and modulates proliferation, survival, differentiation and angiogenesis. Hyperactivation of this pathway is highly implicated in tumorigenesis especially by gain of function mutation of Kras or Braf. Mek position at the end of the pathway seems to be a promising new therapeutic target in the Kras or Braf mutated cancers. In this review, we aimed at describing the Ras/Raf/Mek/Erk pathway, the new therapeutic approaches in solid tumors and their toxicities. However, there seems to be predictives factors of tumor responses to these new agents and mechanisms of resistance that we will tend to analyse.