Merus Announces Publication Of Abstracts On MCLA-129 For Presentation At ESMO Asia Congress 2023

Author: Benzinga Newsdesk | November 27, 2023 12:44am

-  Oral presentation on MCLA-129 in combination with osimertinib as first line therapy, and in previously treated, NSCLC on Sunday, December 3 at 9:40 a.m. SGT 

 

-  Poster presentation on MCLA-129 in previously treated HNSCC on Saturday, December 2 at 17:50 p.m. SGT

 

-  Investor call on Monday, November 27, 2023 8:00 a.m. ET

 

UTRECHT, The Netherlands and CAMBRIDGE, Mass., Nov. 26, 2023 (GLOBE NEWSWIRE) -- Merus N.V. (NASDAQ:MRUS) (Merus, the Company, we, or our), a clinical-stage oncology company developing innovative, full-length multispecific antibodies (Biclonics® and Triclonics®), today announced the publication of two abstracts regarding MCLA-129 on the European Society for Medical Oncology (ESMO) Asia Congress website. The abstracts highlight updated interim clinical data from expansion cohorts in non-small cell lung cancer (NSCLC) and in previously treated head and neck squamous cell carcinoma (HNSCC) for presentation at the ESMO Asia Congress 2023 taking place in Singapore December 1-3, 2023.

"MCLA-129 is now the third asset, together with our other clinical assets petosemtamab and zenocutuzumab, developed from the Merus proprietary Biclonics® platform to demonstrate strong clinical activity," said Bill Lundberg, M.D., President, Chief Executive Officer of Merus. "As we continue the development of MCLA-129, we are planning to take a disciplined capital allocation approach, making focused investments in the program to identify areas of potential differentiation. We remain open to potential business development opportunities as a means to leverage added resources, infrastructure and expertise of a potential partner to more fully evaluate and develop MCLA-129."

MCLA-129 (EGFR x c-MET Biclonics®): Solid Tumors

Interim data included in the abstracts describe data from three expansion cohorts in the open label trial evaluating MCLA-129 in combination with osimertinib, a third generation EGFR TKI, in treatment-naïve EGFR mutant (m) NSCLC and in EGFRm NSCLC that has progressed on osimertinib, as well as MCLA-129 monotherapy in previously treated HNSCC.

Updated clinical data, with additional patients and a later data cutoff date, will be included in the mini-oral presentation on NSCLC and the poster on HNSCC at ESMO Asia next week.

Mini-oral presentation title: Efficacy and safety of MCLA-129, an EGFR x c-MET bispecific antibody, combined with osimertinib, as first-line therapy or after progression on osimertinib in non-small cell lung cancer (NSCLC) 

Observations in the abstract include:  

• As of a May 10, 2023 data cutoff date, 48 patients (pts) with advanced/metastatic EGFRm NSCLC were treated (14/1L, 34/2L+)
  • In the 1L setting, 14 pts were treated, with 10 pts evaluable for response   
    • 2 confirmed partial responses (PRs) and 6 unconfirmed PRs were observed (8/10, 80%; 95% CI 44-98) by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. per investigator assessment; all responses were ongoing as of the data cutoff date
    • 90% disease control rate (DCR) (95% CI 56-100) 
    • 10 weeks (range 2-26) median duration of exposure with 93% continuing treatment
  • In the 2L+ setting, 34 pts were treated, with 22 pts evaluable for response
    • All received prior osimertinib in 1L/2L setting, 71% as the most recent therapy; 24% received prior chemotherapy
    • 6 confirmed PRs and 5 unconfirmed PRs were observed (11/22, 50%; 95% CI 28-72) by RECIST v1.1. per investigator assessment; 9 responses were ongoing as of the data cutoff date, including 4 of the unconfirmed PRs
    • 82% DCR (95% CI 60-95)
    • 10 weeks (range 2-38) median duration of exposure with 68% continuing treatment 
• Early safety assessment in 48 NSCLC pts treated with MCLA-129 plus osimertinib included
  • Most common adverse events (AEs) regardless of causality were infusion related reactions (IRRs; composite term) in 85% (6% ≥ grade(G) 3)
  • Skin toxicity (composite term) in 75% (4% G3)
  • Treatment related interstitial lung disease (ILD)/pneumonitis in five patients (10%), two were G2, two were G3, and one was G5 and one progressed to G5 after the data cutoff date
  • Venous thromboembolic (VTE) events in 15%; 4% treatment related
    
     

Presentation Details:

Session: Thoracic Cancer

Date: Sunday, December 3, 2023

Time: 9:40 -9:45 a.m. SGT

Presentation #: 516MO

Poster presentation title: Efficacy and safety of MCLA-129, an anti-EGFR/c-MET bispecific antibody, in head and neck squamous cell cancer (HNSCC) 

Observations in the abstract include:  

• As of a May 10, 2023 data cutoff date, 18 pts with previously treated HNSCC were treated
  • Pts received median of two lines prior therapy, 89% prior chemotherapy, 78% prior anti-PD-(L)1, 28% prior cetuximab
  • 12 pts were evaluable for response   
    • 2 unconfirmed PRs were observed (2/12, 17%) by RECIST v1.1. per investigator assessment; one response was ongoing as of the data cutoff date  
    • 67% DCR (95% CI 35-90%)
    • 8 weeks (range 2-17) median duration of exposure with 50% continuing on treatment
• Early safety assessment in 18 HNSCC pts treated with MCLA-129 monotherapy included
  • Most common AEs regardless of causality were IRRs (composite term) in 72% (28% ≥ G3), all on cycle 1 day 1, that led to treatment discontinuation in two pts
  • Skin toxicity in 61% (11% G3)
  • No ILD or VTE events were reported

Presentation details:

Session Category: Poster session 

Date: Saturday, December 2, 2023  

Time: 17:50-18:45 p.m. SGT 

Presentation #: 362P 

MCLA-129 Development Strategy

In EGFRm NSCLC, with the strong clinical activity for MCLA-129 shown in the interim data presented today, we are encouraged by the potential for MCLA-129 in the treatment of lung cancer and beyond. We have identified focused investment opportunities. We continue to follow patients with EGFRm NSCLC treated with MCLA-129 in combination with osimertinib, to evaluate potential for biomarkers as a means to maximize efficacy, while proactively addressing safety signals seen to date. 

We plan to start a cohort of MCLA-129 in combination with chemotherapy in 2L+ EGFRm NSCLC in the first quarter of next year. 

Additionally, we remain interested and are continuing investigation of cohort B evaluating MCLA-129 in patients with MET exon14 skipping NSCLC. We also remain interested in exploring partnering MCLA-129 with other companies to sufficiently resource the development of MCLA-129 and potential benefit it may have for patients.

In HNSCC, based on the interim data, we observed clinical activity with MCLA-129. However, we view the clinical activity with MCLA-129 monotherapy as of the cutoff date as modest, with 2 unconfirmed partial responses or 17%. The safety profile was manageable, and there were no reported ILD or VTE events. Our assessment of this cohort is that the clinical activity of MCLA-129 in second line head and neck cancer appears substantially inferior to that of our lead asset petosemtamab, and only on par with other EGFR or cetuximab-based monoclonal or bispecific antibodies as monotherapy in a similar setting. We believe this efficacy is insufficient to warrant further development in head and neck cancer.

Zenocutuzumab (Zeno or MCLA-128: HER2 x HER3 Biclonics®): NRG1 fusion (NRG1+) cancer and other solid tumors

An abstract for an encore of a recent ESMO Congress 2023 presentation on zenocutuzumab interim clinical data from the eNRGy trial and Early Access Program in patients with NRG1 fusion (NRG1+) NSCLC has also been accepted for presentation at ESMO Asia.   

Presentation details:

Title: Durable efficacy of zenocutuzumab, a HER2 x HER3 bispecific antibody, in advanced NRG1 fusion-positive (NRG1+) non-small cell lung cancer (NSCLC) 

Session Category: Poster session 

Date: Saturday, December 2, 2023  

Time: 17:50-18:45 p.m. SGT 

Presentation #: 595P 

As full presentations become available at the ESMO Asia Congress 2023, they will contemporaneously be available on the Merus website. 

Company Conference Call and Webcast Information

Merus will hold a conference call and webcast for investors on November 27, 2023 at 8:00 a.m. ET. A replay will be available after the completion of the call in the Investors and Media section of our website for a limited time.

Date and Time: November 27, 2023 at 8:00 a.m. ET

Webcast link: Available on our website

Dial-in: Toll-Free: 1 (800) 715-9871 / International: 1 (646) 307-1963

Conference ID: 2833671

Posted In: MRUS