On September 17, 2020 Daiichi Sankyo Company, Limited (hereafter, Daiichi Sankyo) reported that updated phase 1 data for patritumab deruxtecan (U3-1402), a HER3 directed DXd antibody drug conjugate (ADC), including the first results from one cohort of the dose expansion part of the study in patients with epidermal growth factor receptor (EGFR)-mutated metastatic or unresectable non-small cell lung cancer (NSCLC) after failing treatment with a tyrosine kinase inhibitor (TKI) (Press release, Daiichi Sankyo, SEP 17, 2020, View Source [SID1234565334]). The late-breaking data (Abstract #LBA62) were highlighted during a mini-oral presentation today at the European Society of Medical Oncology (ESMO) (Free ESMO Whitepaper) Virtual Congress 2020 (#ESMO20).
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
Lung cancer is the most common cancer and the leading cause of cancer mortality worldwide, with most lung cancers diagnosed at an advanced or metastatic stage.[1],[2] Approximately 15-50 percent of NSCLC patients have an EGFR mutation.[3] In patients with NSCLC, it is estimated that approximately 83 percent express the HER3 protein , which can be associated with an increased incidence of metastases, reduced survival and resistance to standard of care cancer treatments.[4],[5]
Prior to receiving treatment with patritumab deruxtecan, patients in the study had received a median of four prior therapies. All patients had been previously treated with an EGFR TKI, with the majority receiving osimertinib (86 percent); 90 percent of patients received platinum-based chemotherapy; and 40 percent had received an anti-PD-1/PD-L1 therapy. Forty seven percent of evaluable patients in the study had a history of brain metastases that were stable at the time of study entry.
The preliminary objective response rate (ORR), assessed by blinded independent central review, was 25 percent in 56 evaluable patients treated with patritumab deruxtecan monotherapy (5.6 mg/kg) in the dose escalation and dose expansion parts of the study. One patient achieved a complete response (CR) and 13 achieved a partial response (PR). At the time of data cut-off, three additional PRs were awaiting confirmation, and six patients had only one tumor evaluation. The disease control rate (DCR) was 70 percent with a median duration of response (DOR) of 6.9 months. Stable disease was observed in 45 percent of patients.
"These initial responses seen with patritumab deruxtecan in patients with significantly pre-treated EGFR-mutated NSCLC and diverse mechanisms of resistance to EGFR therapy are very encouraging, considering the lack of approved effective therapies in this setting," said Helena Yu, MD, Medical Oncologist, Memorial Sloan Kettering Cancer Center, and a trial investigator and presenter of the late breaking data. "These data provide support that targeting HER3 using an antibody drug conjugate might be a treatment strategy that can overcome the various mechanisms of resistance in patients with EGFR-mutated NSCLC who have progressed on currently available treatment options."
The overall safety and tolerability profile of patritumab deruxtecan was consistent with that seen in the dose escalation phase of the study. The most common TEAEs of any grade, occurring in ≥25 percent of patients who received patritumab deruxtecan (5.6 mg/kg) included fatigue (58 percent), nausea (54 percent), thrombocytopenia (53 percent), decreased appetite (35 percent), neutropenia (33 percent), vomiting (30 percent), alopecia (30 percent), anemia (26 percent) and constipation (25 percent). The most common TEAEs of grade ≥3 severity occurring in more than 10 percent of patients were thrombocytopenia (28 percent) and neutropenia (19 percent). Five patients (9 percent) experienced a TEAE that led to treatment discontinuation. There were three cases (5 percent) of confirmed drug-related interstitial lung disease (ILD), as determined by an independent adjudication committee.
"HER3 is frequently overexpressed in NSCLC and provides an attractive target for therapeutic intervention in tumors with a broad range of resistance mechanisms to standard therapies," said Gilles Gallant, BPharm, PhD, FOPQ, Senior Vice President, Global Head, Oncology Development, Oncology R&D, Daiichi Sankyo. "These preliminary results showing disease control with patritumab deruxtecan in patients over a short period of follow-up are very encouraging and need to be confirmed with longer term follow-up. Based on these findings we plan to initiate a phase 2 trial of patritumab deruxtecan in patients with advanced or metastatic EGFR-mutated NSCLC."
CI, confidence interval; ORR, objective response rate; CR, complete response; DCR, disease control rate; DoR, duration of response; PR, partial response; SD, stable disease; PD, progressive disease; NE, not evaluable
i Patritumab deruxtecan 5.6 mg/kg dose in dose escalation and cohort 1 of dose expansion included in efficacy analysis set
ii Data cut-off of April 30, 2020
iii Median follow-up time was 5 months, with 28 patients continuing to receive treatment at the time of data cut-off
iv 22/56 (39%) patients had best percentage decrease in sum of tumor diameters ≥ 30%.
v ORR is CR+PR
vi DCR is CR + PR +SD
About the Study
The global, multicenter, open label, two-part phase 1 study is evaluating patritumab deruxtecan in patients with metastatic or unresectable EGFR-mutated NSCLC whose disease has progressed after standard therapy including an EGFR TKI.
The dose escalation part of the study evaluated patients with metastatic or unresectable EGFR-mutated NSCLC who experienced disease progression on erlotinib, gefitinib, dacomitinib or afatinib and tested negative for the T790M mutation or who experienced disease progression on osimertinib regardless of T790M status. The primary objective of the dose escalation phase was to assess the safety and tolerability of patritumab deruxtecan and determine the recommended dose for expansion (RDE). Data from the dose escalation were presented at the 2019 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting and the 2019 World Conference on Lung Cancer (WCLC).
The dose expansion part of the study is evaluating patritumab deruxtecan at the RDE (5.6 mg/kg) in three cohorts. Cohort 1 includes patients with metastatic or unresectable EGFR-mutated NSCLC who experienced disease progression after taking one or more EGFR tyrosine kinase inhibitor (TKI) and one or more platinum based chemotherapy regimens. Cohort 2 includes patients with squamous or non-squamous NSCLC without EGFR activating mutations. Cohort 3 includes patients with NSCLC with EGFR mutations including any histology other than combined small cell and non-small cell lung cancer; patients in Cohort 3 will be randomized 1:1 to receive the RDE regimen (Cohort 3a) or an escalating up-titration regimen of patritumab deruxtecan (Cohort 3b).
The primary objective of the dose expansion phase of the study is to assess efficacy as measured by confirmed ORR of patritumab deruxtecan. Secondary study endpoints include investigator assessed ORR; safety, tolerability and preliminary efficacy; and characterization of the pharmacokinetics of patritumab deruxtecan. The study is currently enrolling patients at multiple sites in the US, Europe, Japan and other countries in Asia. For more information, visit ClinicalTrials.gov.
About Non-Small Cell Lung Cancer
Lung cancer is the most common cancer and the leading cause of cancer mortality worldwide; there were an estimated 2.1 million new cases of lung cancer in 2018 and 1.8 million deaths.1 Most lung cancers are diagnosed at an advanced or metastatic stage.2 Non-small cell lung cancer (NSCLC) accounts for 80 to 85 percent of all lung cancers.[6] The introduction of targeted therapies and checkpoint inhibitors in the past decade has improved the treatment landscape for patients with advanced or metastatic NSCLC; however, the prognosis is particularly poor among patients who have progressed after treatment with standard therapies. For those who are not eligible for current treatments, or whose cancer continues to progress, new therapeutic approaches are needed.[7]
EGFR mutation is a well-established oncogenic target for management of advanced stage NSCLC.[8] For patients with advanced EGFR-mutated NSCLC, targeted therapy with EGFR TKIs offers higher response rates and progression-free survival compared to chemotherapy.8 However, most patients eventually develop resistance to such drugs, at which time standard treatment options are limited.[9] Clinical resistance to EGFR TKIs has been linked to multiple gene-based mechanisms, and in many cases, the underlying cause remains unknown.[10],[11],[12]
About HER3
HER3 is a member of the EGFR family of tyrosine kinase receptors, which are associated with aberrant cell proliferation and survival.[13] HER3 expression has been associated with an increased incidence of metastases and reduced survival in patients with NSCLC, with expression frequency reported to be as high as 83 percent.4,5 The majority of EGFR-mutated NSCLCs show some level of HER3 expression.[14],[15] Currently, no HER3 directed therapies are approved for any cancer.
About Patritumab Deruxtecan
Patritumab deruxtecan (U3-1402) is one of three lead DXd antibody drug conjugates (ADC) in the oncology pipeline of Daiichi Sankyo.
ADCs are targeted cancer medicines that deliver cytotoxic chemotherapy ("payload") to cancer cells via a linker attached to a monoclonal antibody that binds to a specific target expressed on cancer cells. Designed using Daiichi Sankyo’s proprietary DXd ADC technology, patritumab deruxtecan is comprised of a human anti-HER3 antibody attached to a topoisomerase I inhibitor payload by a tetrapeptide-based linker.
Patritumab deruxtecan is currently being evaluated in a phase 1 study in previously treated patients with metastatic or unresectable NSCLC and a phase 1/2 study in patients with HER3 expressing metastatic breast cancer. A phase 2 study of patritumab deruxtecan has recently been initiated in patients with advanced or metastatic colorectal cancer who are resistant, refractory, or intolerant to at least two prior lines of systemic therapy.
Patritumab deruxtecan is an investigational agent that has not been approved for any indication in any country. Safety and efficacy have not been established.
About Daiichi Sankyo Cancer Enterprise
The mission of Daiichi Sankyo Cancer Enterprise is to leverage our world-class, innovative science and push beyond traditional thinking to create meaningful treatments for patients with cancer. We are dedicated to transforming science into value for patients, and this sense of obligation informs everything we do. Anchored by our DXd antibody drug conjugate (ADC) technology, our powerful research engines include biologics, medicinal chemistry, modality and other research laboratories in Japan, and Plexxikon Inc., our small molecule structure-guided R&D center in Berkeley, CA. For more information, please visit: www.DSCancerEnterprise.com.