Light Chain Bioscience Announces Proffered Paper Oral Presentation at ESMO 2025 for Safety and Efficacy of NI-1801 in Platinum Resistant Ovarian Cancer patients
Geneva, 13 October 2025 - Light Chain Bioscience, a clinical-stage biotechnology company advancing the next generation of bispecific antibodies to treat cancer, reports positive results from a Phase 1/1b study of NI-1801 in patients with heavily pretreated Platinum Resistant Ovarian Cancer (PROC) at the 2025 European Society of Medical Oncology (ESMO) Congress. Early data (cutoff: May 2025) are summarized in the abstract published today. More mature data (cutoff: August 2025), including overall survival, will be presented at ESMO 2025 as a Proffered Paper oral presentation on 20 October.
NI-1801 is a first-in-class bispecific antibody selectively targeting the innate immune checkpoint CD47 on mesothelin-expressing cancer cells. Mesothelin is over-expressed in ovarian cancer cells and represents an important target for potential therapies.
The published abstract summarizes data from a Phase 1 monotherapy study and Phase 1b study in combination with pembrolizumab in heavily pretreated ovarian cancer patients (≥ 4 prior chemotherapy lines). NI-1801 as monotherapy demonstrated encouraging signs of activity in fragile, heavily pretreated patients with mesothelin-expressing PROC. NI-1801 in combination with pembrolizumab showed enhanced efficacy. Notably, this clinical benefit was achieved with a chemotherapy-free regimen, which was well tolerated and had a favorable safety profile.
Dr. Jose Saro, Chief Medical Officer, Light Chain Bioscience, said: "We are delighted to report substantial clinical benefit of NI-1801 in this difficult-to-treat ovarian cancer patient population. These findings indicate the potential of NI-1801 to positively impact the management of this devastating disease with a chemotherapy-free regimen. We are excited to be reporting more mature data at ESMO later this week in a Proffered Paper oral presentation later this week.”
Nicolas Fischer, CEO of Light Chain Bioscience, said: “These promising results confirm our long-held conviction that bispecific antibodies targeting CD47 have a fundamentally different therapeutic window than anti-CD47 monoclonal antibodies, which have faced major setbacks.”
As a bispecific antibody that targets both CD47 and mesothelin, NI-1801enables a tumor-specific blockade of CD47, which helps the immune system to selectively attack cancer cells, but not healthy CD47-positive cells. CD47 is expressed on virtually all cells of the human body, including red blood cells.
Details of the Proffered Paper oral presentation are as follows:
Title (Abstract #1512O): NI-1801, a mesothelin x CD47 bispecific antibody: Safety and activity as single agent and in combination with pembrolizumab, in heavily pretreated (≥ 4 prior lines) mesothelin expressing platinum resistant epithelial ovarian cancer patients
Presenter: Dr. Thibault De La Motte Rouge, MD, Research Director, Centre Eugène Marquis, Rennes, France.
Lecture Date and Time: Monday 20 October - 10:55 - 11:05
About NI-1801
Light Chain Bioscience’s most advanced asset, NI-1801, is a first-in-class bispecific antibody selectively targeting the innate immune checkpoint CD47 on mesothelin-expressing cancer cells, as a potential treatment for ovarian and mesothelin-positive cancers. NI-1801 is being evaluated in a Phase 1 trial in patients with heavily pretreated platinum resistant ovarian cancer (PROC). NI-1801 is also being evaluated in a Phase 2 randomized trial in PROC patients having received 1-3 prior chemotherapy lines.
About Light Chain Bioscience
Light Chain Bioscience, based in Geneva, Switzerland, is a clinical-stage biotechnology company developing next-generation bispecific antibodies for oncology and immune-related diseases. Leveraging its proprietary κλ body platform, Light Chain Bioscience designs fully human IgG bispecifics with potent and selective biological activity. Its lead programs include selective CD47 blockers for solid tumors and CD28-targeted antibodies such as NI-3201, a PD-L1×CD28 bispecific antibody designed to restore anti-tumor immunity. Light Chain Bioscience has more than two decades of expertise in antibody development and has brought seven monoclonal antibodies through to clinical development stage. The company is advancing innovative immunotherapies that engage both innate and adaptive immunity to achieve durable clinical benefit. For more information, visit https://www.lightchainbio.com/
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Charis Gresser and Ayesha Bharmal, Brunswick Group
