Tokyo - Results from the HERTHENA-Lung01 phase 2 trial showed that patritumab deruxtecan (HER3-DXd) demonstrated clinically meaningful and durable responses in patients with EGFR-mutated locally advanced or metastatic non-small cell lung cancer (NSCLC) following disease progression with an EGFR TKI and platinum-based chemotherapy.

These data were presented today during an oral presentation (OA05.03) at the 2023 World Conference on Lung Cancer (#WCLC23) and simultaneously published in the Journal of Clinical Oncology.

Patritumab deruxtecan is a specifically engineered potential first-in-class HER3 directed antibody drug conjugate (ADC) designed using Daiichi Sankyo's (TSE: 4568) proprietary DXd ADC technology. NSCLC accounts for approximately 85% of all lung cancers - 55% having distant spread at diagnosis - with EGFR-activating mutations occurring in 14% to 38% of all NSCLC tumors worldwide. 1,2,3 After disease progression following treatment with an EGFR TKI and platinum-based chemotherapy, currently available therapies offer limited efficacy, highlighting the need for new approaches to improve outcomes.3,4

A confirmed objective response rate (ORR) of 29.8% (95% CI: 23.9-36.2) was observed with patritumab deruxtecan (5.6 mg/kg) in 225 patients with EGFR-mutated NSCLC as assessed by blinded independent central review (BICR). One complete response (CR), 66 partial responses (PRs) and 99 cases of stable disease (SD) were seen. A median duration of response (DOR) of 6.4 months (95% CI: 4.9-7.8) and a disease control rate (DCR) of 73.8% (95% CI: 67.5-79.4) were observed. Median progression-free survival (PFS) was 5.5 months (95% CI: 5.1-5.9) and median overall survival (OS) was 11.9 months (95% CI: 11.2-13.1) as of snapshot data cutoff of May 18, 2023.

Efficacy outcomes were consistent across subgroups including a subset of 209 patients previously treated with a third-generation EGFR TKI and platinum-based chemotherapy. Anti-tumor activity with patritumab deruxtecan was observed across diverse mechanisms of EGFR TKI resistance and across a broad range of pretreatment tumor HER3 membrane expression. In a subset of 30 patients with brain metastases at baseline and no prior radiotherapy treatment, an intracranial ORR of 33.3% (95% CI: 17.3-52.8%) was observed as assessed by central nervous system (CNS) BICR. In these patients, nine intracranial CRs, one intracranial PR and 13 cases of SD were seen. A CNS DOR of 8.4 months (95% CI: 5.8-9.2) was observed.

'The results from HERTHENA-Lung01 provide compelling evidence of efficacy of patritumab deruxtecan in heavily pretreated patients with advanced EGFR-mutated non-small cell lung cancer,' said Helena Yu, MD, Associate Attending Physician, Memorial Sloan Kettering Cancer Center. 'The clinically meaningful efficacy observed across a broad range of HER3 expression and diverse mechanisms of EGFR TKI resistance as well as the anti-tumor activity seen in patients with brain metastases, underscore the potential of patritumab deruxtecan to become an important treatment option for a population of patients with lung cancer who have limited treatment options.' 'Disease progression is inevitable in patients with previously treated and relapsed metastatic EGFRmutated non-small cell lung cancer, reinforcing the need for new and innovative treatments across diverse mechanisms of resistance,' said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. 'The results from HERTHENA-Lung01, coupled with early trial results, show that patritumab deruxtecan demonstrates clinically meaningful and durable responses, illustrating the potential of this HER3 directed antibody drug conjugate to become a new standard of care for this patient population with high unmet medical need. These data will support our ongoing discussions with health authorities including our planned submission in the U.S.'

The safety profile of patritumab deruxtecan observed in HERTHENA-Lung01 was consistent with previous clinical trials with a low rate (7.1%) of treatment discontinuation due to treatment-emergent adverse events (TEAEs) at the time of primary data cutoff of November 21, 2022. Grade 3 or higher TEAEs occurred in 64.9% of patients. The most common (>5%) grade 3 or higher TEAEs were thrombocytopenia (21%), neutropenia (19%), anemia (14%), leukopenia (10%), fatigue (6%), hypokalemia (5%) and asthenia (5%). Twelve patients (5.3%) had confirmed treatment-related interstitial lung disease (ILD) as determined by an independent adjudication committee. The majority of ILD events were low grade with one grade 1 event and eight grade 2 events. Two grade 3, zero grade 4 and one grade 5 ILD event were observed.

In HERTHENA-Lung01, 51% of patients (n=115) had a history of CNS metastases; 32% (n=72) and 33% of patients (n=75) had brain or liver metastases at baseline by BICR, respectively. In the trial, 63% (n=142) and 36% (n=82) of patients had either an EGFR exon 19 deletion or exon 21 L858R mutation detected at baseline, respectively, and one patient had both. Patients were heavily pretreated receiving a median of three prior lines of systemic therapy in the locally advanced/metastatic setting (range, 1-11), including platinum-based chemotherapy (100%), third generation EFGR TKI (93%) and immunotherapy (40%). As of the snapshot data cutoff of May 18, 2023, the median trial duration was 18.9 (14.9-27.5) months, and 13 patients were continuing to receive patritumab deruxtecan.

About Daiichi Sankyo

Daiichi Sankyo is an innovative global healthcare company contributing to the sustainable development of society that discovers, develops and delivers new standards of care to enrich the quality of life around the world. With more than 120 years of experience, Daiichi Sankyo leverages its world-class science and technology to create new modalities and innovative medicines for people with cancer, cardiovascular and other diseases with high unmet medical needs.

Contact:

Koji Ogiwara

Email: ogiwara.koji.ay@daiichisankyo.co.jp

Tel: +81 3 6225 1126

(C) 2023 Electronic News Publishing, source ENP Newswire