Petosemtamab

- Petosemtamab in combination with pembrolizumab in 1L PD-L1+ r/m HNSCC phase 2 trial demonstrates 63% response rate observed among 43 evaluable patients and 79% overall survival rate at 12-months - Based on the Company’s current operating plan, existing cash, cash equivalents, including successful public offering raising $345M gross proceeds, and marketable securities expected to fund Merus’ operations at least into 2028 UTRECHT, The Netherlands and CAMBRIDGE, Mass. , Aug. 05, 2025 (GLOBE NEWSWIRE) -- Merus N.V. (Nasdaq: MRUS) (Merus, the Company, we, or our), an oncology company developing innovative, full-length multispecific antibodies and antibody drug conjugates (Biclonics®, Triclonics® and ADClonics®), today announced financial results for the second quarter and provided a business update. “We were excited to share the unprecedented efficacy of petosemtamab with pembrolizumab in first-line head and neck cancer at 2025 ASCO®, and were thrilled by the response from clinicians and KOLs, which we believe continues to drive strong phase 3 site activation and support our expectation that both phase 3 trials will be substantially enrolled by year end 2025,” said Bill Lundberg, M.D., President, Chief Executive Officer of Merus. “Additionally, I believe these data substantially enhance the likelihood of clinical success of petosemtamab. We are looking forward to providing initial clinical data on mCRC in the second half of 2025.” Petosemtamab (MCLA-158: EGFR x LGR5 Biclonics®): Solid TumorsLiGeR-HN1 phase 3 trial in 1L recurrent/metastatic (r/m) head and neck squamous cell carcinoma (HNSCC) and LiGeR-HN2 phase 3 trial in 2/3L r/m HNSCC enrolling – with both trials expected to be substantially enrolled by YE25 and potential top line interim readout for one or both trials in 2026; phase 2 trial in 1L, 2L and 3L+ metastatic colorectal cancer (mCRC) enrolling; mCRC initial clinical data planned for 2H25 Merus provided updated interim clinical data from the phase 2 trial of petosemtamab with pembrolizumab as 1L treatment for PD-L1+ (CPS≥1) r/m HNSCC at the 2025 American Society of Clinical Oncology® (ASCO®) Annual Meeting, demonstrating a 63% response rate among 43 evaluable patients and a 79% overall survival rate at 12 months. The presentation was detailed in our press release, Merus’ Petosemtamab with Pembrolizumab Interim Data Demonstrates Robust Efficacy and Durability in 1L PD-L1+ r/m HNSCC ( May 22 , 2025). LiGeR-HN1, a phase 3 trial evaluating the efficacy and safety of petosemtamab in combination with pembrolizumab in 1L PD-L1+ r/m HNSCC compared to pembrolizumab, and LiGeR-HN2, a phase 3 trial evaluating the efficacy and safety of petosemtamab in 2/3L HNSCC compared to standard of care, are enrolling and we expect both trials to be substantially enrolled by YE25. Merus believes a randomized registration trial in HNSCC with an overall response rate endpoint could potentially support accelerated approval and the overall survival results from the same study could potentially verify its clinical benefit to support regular approval for the Company’s phase 3 trial in 1L, and in phase 3 trial in 2/3L HNSCC. We expect to provide topline interim readout of one or both phase 3 registration trials in 2026. In February 2025 , the U.S. Food and Drug Administration (FDA) granted Breakthrough Therapy designation (BTD) to petosemtamab in combination with pembrolizumab for the first-line treatment of adult patients with recurrent or metastatic programmed death-ligand 1 (PD-L1) positive HNSCC with combined positive score (CPS) ≥ 1. This designation was detailed in our press release, Petosemtamab Granted Breakthrough Therapy Designation by the U.S. FDA for 1L PD-L1 Positive Head and Neck Squamous Cell Carcinoma ( February 18, 2025 ). BTD was also granted for petosemtamab monotherapy for the treatment of patients with recurrent or metastatic HNSCC whose disease has progressed following treatment with platinum based chemotherapy and an anti-programmed cell death receptor-1 (PD-1) or anti-programmed death ligand 1 (PD-L1) antibody, detailed in our press release, Petosemtamab granted Breakthrough Therapy Designation by the U.S. FDA ( May 13 , 2024). Merus provided updated interim clinical data on petosemtamab monotherapy in 2L+ r/m HNSCC at the European Society for Medical Oncology Asia Congress , demonstrating a 36% response rate among 75 evaluable patients. The oral presentation was detailed in our press release, Merus’ Petosemtamab Monotherapy Interim Data Continues to Demonstrate Clinically Meaningful Activity in 2L+ r/m HNSCC ( Dec. 7 , 2024). A phase 2 trial evaluating petosemtamab in combination with standard chemotherapy in 1L and 2L mCRC, and as monotherapy in heavily pretreated (3L+) mCRC, is enrolling. We expect to provide initial clinical data for petosemtamab in mCRC in 2H25. BIZENGRI® (zenocutuzumab-zbco: HER2 x HER3 Biclonics®)Approved by FDA for adults with pancreatic adenocarcinoma or non–small cell lung cancer (NSCLC) that are advanced unresectable or metastatic and harbor a neuregulin 1 (NRG1) gene fusion who have disease progression on or after prior systemic therapy Merus has exclusively licensed to Partner Therapeutics, Inc. (PTx) the right to commercialize BIZENGRI® for the treatment of NRG1+ cancer in the U.S. This was detailed in our press release, Merus and Partner Therapeutics Announce License Agreement for the U.S. Commercialization of Zenocutuzumab in NRG1 Fusion-Positive Cancer ( December 2 , 2024). MCLA-129 (EGFR x c-MET Biclonics®): Solid TumorsInvestigation of MCLA-129 is ongoing in METex14 NSCLC; phase 2 trial in combination with chemotherapy in 2L+ EGFR mutant (EGFRm) NSCLC enrolling MCLA-129 is subject to a collaboration and license agreement with Betta Pharmaceuticals Co. Ltd. (Betta), which permits Betta to develop MCLA-129, and potentially commercialize exclusively in China, while Merus retains global rights outside of China. Collaborations Incyte CorporationSince 2017, Merus has been working with Incyte Corporation (Incyte) under a global collaboration and license agreement focused on the research, discovery and development of bispecific antibodies utilizing Merus’ proprietary Biclonics® technology platform. For each program under the collaboration, Merus receives reimbursement for research activities and is eligible to receive potential development, regulatory and commercial milestones and sales royalties for any products, if approved. During the second quarter of 2025, Merus received the milestone payment of $1 million for the candidate nomination of a discovery program under the collaboration. Eli Lilly and CompanyIn January 2021, Merus and Eli Lilly and Company (Lilly) announced a research collaboration and exclusive license agreement to develop up to three CD3-engaging T-cell re-directing bispecific antibody therapies utilizing Merus’ Biclonics® platform and proprietary CD3 panel along with the scientific and rational drug design expertise of Lilly. The collaboration is progressing well with two programs advancing through preclinical development. Gilead SciencesIn March 2024, Merus and Gilead Sciences announced a collaboration to discover novel antibody based trispecific T-cell engagers using Merus’ patented Triclonics® platform. Under the terms of the agreement, Merus will lead early-stage research activities for two programs, with an option to pursue a third. Gilead will have the right to exclusively license programs developed under the collaboration after the completion of select research activities. If Gilead exercises its option to license any such program from the collaboration, Gilead will be responsible for additional research, development and commercialization activities for such program. The collaboration is progressing well with two programs advancing through preclinical development. Ono PharmaceuticalIn 2018, the Company granted Ono Pharmaceutical Co., Ltd. (Ono) an exclusive, worldwide, royalty-bearing license, with the right to sublicense, research, test, make, use and market a limited number of bispecific antibody candidates based on Merus’ Biclonics® technology platform directed to an undisclosed target combination. BiohavenIn January 2025 , Merus and Biohaven announced a research collaboration and license agreement to co-develop three novel bispecific antibody drug conjugates (ADCs), leveraging Merus’ leading Biclonics® technology platform, and Biohaven’s next-generation ADC conjugation and payload platform technologies. Under the terms of the agreement, Biohaven is responsible for the preclinical ADC generation of three Merus bispecific antibodies under mutually agreed research plans. The agreement includes two Merus bispecific programs generated using the Biclonics® platform, and one program under preclinical research by Merus. Each program is subject to mutual agreement for advancement to further development, with the parties then sharing subsequent external development costs and commercialization, if advanced. Corporate ActivitiesCompleted public offering raising $345M gross proceedsThis equity raise is detailed in a press release: Merus N.V. Announces Pricing of Public Offering of Common Shares ( June 4 , 2025). Cash Runway, existing cash, cash equivalents and marketable securities expected to fund Merus’ operations at least into 2028 As of June 30, 2025, Merus had $892 million cash, cash equivalents and marketable securities. Based on the Company’s current operating plan, the existing cash, cash equivalents and marketable securities are expected to fund Merus’ operations at least into 2028. Second Quarter 2025 Financial Results Total revenue for the three months ended June 30, 2025 increased by $1.5 million as compared to the three months ended June 30, 2024 , primarily as a result of increases in Incyte revenue of $1.5 million , PTx revenue of $0.5 million , and Gilead revenue of $0.1 million , partially offset by a decrease in Lilly revenue of $0.6 million . Research and development (R&D) expense for the three months ended June 30, 2025 increased by $44.8 million as compared to the three months ended June 30, 2024 . The increase in R&D expense is primarily driven by an increase of $37.9 million in clinical trial support provided by contract manufacturing and development organizations and contract research organizations, most of which is related to the petosemtamab clinical trials. The increase is also due to increases in personnel related expenses including share-based compensation of $7.2 million . General and administrative expense for the three months ended June 30, 2025 increased by $2.7 million as compared to the three months ended June 30, 2024 , primarily as a result of increases in personnel related expenses including share-based compensation of $5.0 million , increases in facilities and depreciation expense of $0.7 million , increases in legal expenses of $0.6 million , and increases in travel expenses of $0.2 million , partially offset by decreases in consulting expenses of $3.6 million and decreases in intellectual property and license expenses of $0.3 million . Total revenue for the six months ended June 30, 2025 increased by $20.1 million as compared to the six months ended June 30, 2024 , primarily as a result of commercial material revenue sold to PTx of $13.3 million and increases in collaboration revenue of $6.8 million . The collaboration revenue increase is primarily due to increases in Biohaven upfront payment amortization of $5.1 million . Research and development expense for the six months ended June 30, 2025 increased by $86.3 million as compared to the six months ended June 30, 2024 . The increase in R&D expense is primarily driven by an increase of $73.7 million in clinical trial support provided by contract manufacturing and development organizations and contract research organizations, most of which is related to the petosemtamab clinical trials. General and administrative expense for the six months ended June 30, 2025 increased by $8.7 million as compared to the six months ended June 30, 2024 , primarily as a result as a result of increases in personnel related expenses including share-based compensation of $10.3 million , increases in facilities and depreciation expense of $1.0 million , increases in legal expenses of $0.8 million , increases in finance and human resources expenses of $0.1 million and increases in travel expenses of $0.1 million , partially offset by decreases in consulting expenses of $3.4 million . Other income (loss), net consists of interest earned and fees paid on our cash and cash equivalents held on account, accretion of investment earnings and net foreign exchange (losses) gains on our foreign denominated cash, cash equivalents and marketable securities. Other gains or losses relate to the issuance and settlement of financial instruments. About Merus N.V. Merus is an oncology company developing innovative full-length human bispecific and trispecific antibody therapeutics, referred to as Multiclonics®. Multiclonics® are manufactured using industry standard processes and have been observed in preclinical and clinical studies to have several of the same features of conventional human monoclonal antibodies, such as long half-life and low immunogenicity. For additional information, please visit Merus’ website, LinkedIn and Bluesky. Forward-Looking Statements This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this press release that do not relate to matters of historical fact should be considered forward-looking statements, including without limitation, statements regarding the content and timing of clinical trials, data readouts and clinical, regulatory, strategy and development updates for our product candidates; our ongoing LiGeR-HN1, LiGeR-HN2 and phase 2 mCRC trials for petosemtamab; our planned initial clinical data update on the phase 2 investigation of petosemtamab in mCRC in the 2H of 2025; the potential impact, if any, on the receipt of BTD by the FDA for petosemtamab in combination with pembrolizumab in 1L PD-L1+ r/m HNSCC and petosemtamab monotherapy for the treatment of patients with recurrent or metastatic HNSCC whose disease has progressed following treatment with platinum based chemotherapy and a PD-1 or PD-L1 antibody; our expectation that the LiGeR-HN1 and LiGeR-HN2 trials will be substantially enrolled by year-end; our expectation of reporting a topline interim readout of one or both phase 3 registration trials in 2026; our belief that a randomized registration trial in HNSCC with an overall response rate endpoint could potentially support accelerated approval and the overall survival results from the same study could potentially verify its clinical benefit to support regular approval in our phase 3 trial in 1L, and in phase 3 trial in 2/3L HNSCC; our statements regarding the sufficiency of our cash, cash equivalents and marketable securities, and expectation that it will fund the Company at least into 2028; the continued investigation of MCLA-129 and enrolling of patients in the investigation of MCLA-129 in combination with chemotherapy in 2L+ EGFRm NSCLC; the benefits of the license from Merus to PTx for the commercialization of Bizengri® in the US for NRG1+ cancer, collaborations between Incyte and Merus, Lilly and Merus, Gilead and Merus, Biohaven and Merus, and license agreement between Ono and Merus; and the potential of those licenses and collaborations for future value generation, including whether and when Merus will receive any future payments, including milestones or royalties, and the amounts of such payments; whether any programs under the collaboration will be successful; and our collaboration and license agreement with Betta, which permits Betta to develop MCLA-129 and potentially commercialize exclusively in China , while Merus retains full ex- China rights, including any future clinical development by Betta of MCLA-129. These forward-looking statements are based on management’s current expectations. These statements are neither promises nor guarantees, but involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements, including, but not limited to, the following: our need for additional funding, which may not be available and which may require us to restrict our operations or require us to relinquish rights to our technologies or antibody candidates; potential delays in regulatory approval, which would impact our ability to commercialize our product candidates and affect our ability to generate revenue; the lengthy and expensive process of clinical drug development, which has an uncertain outcome; the unpredictable nature of our early stage development efforts for marketable drugs; potential delays in enrollment of patients, which could affect the receipt of necessary regulatory approvals; our reliance on third parties to conduct our clinical trials and the potential for those third parties to not perform satisfactorily; impacts of the volatility in the global economy, including global instability, including the ongoing conflicts in Europe and the Middle East ; we may not identify suitable Biclonics® or bispecific antibody candidates under our collaborations or our collaborators may fail to perform adequately under our collaborations; our reliance on third parties to manufacture our product candidates, which may delay, prevent or impair our development and commercialization efforts; protection of our proprietary technology; our patents may be found invalid, unenforceable, circumvented by competitors and our patent applications may be found not to comply with the rules and regulations of patentability; we may fail to prevail in potential lawsuits for infringement of third-party intellectual property; and our registered or unregistered trademarks or trade names may be challenged, infringed, circumvented or declared generic or determined to be infringing on other marks. These and other important factors discussed under the caption “Risk Factors” in our Quarterly Report on Form 10-Q for the period ended June 30, 2025 , filed with the Securities and Exchange Commission , or SEC , on August 5, 2025 , and our other reports filed with the SEC , could cause actual results to differ materially from those indicated by the forward-looking statements made in this press release. Any such forward-looking statements represent management’s estimates as of the date of this press release. While we may elect to update such forward-looking statements at some point in the future, we disclaim any obligation to do so, even if subsequent events cause our views to change, except as required under applicable law. These forward-looking statements should not be relied upon as representing our views as of any date subsequent to the date of this press release. Multiclonics®, Biclonics®, Triclonics®, ADClonics® and BIZENGRI® are registered trademarks of Merus N.V. Please see full Prescribing Information, including Boxed WARNING, at BIZENGRI.com/pi. Reference: 1. BIZENGRI. Prescribing information. Merus N.V.; 2024. Source: Merus N.V.