Lonza and Antharis Forge Alliance to Unleash Dual-Payload ADCs on GI Cancers

BASEL, Switzerland and SAN DIEGO, CA – June 15, 2026 – In a significant move aimed at reshaping the therapeutic landscape for gastrointestinal (GI) cancers, Swiss manufacturing giant Lonza has granted an exclusive, target-specific license to Antharis Therapeutics, a biopharmaceutical innovator. The agreement provides Antharis with access to Lonza's clinically validated dual-payload antibody-drug conjugate (ADC) technology, setting the stage for a new generation of cancer therapies designed to overcome the most persistent challenges in oncology.

This collaboration will initially bolster Antharis's lead ADC program, which is poised to enter clinical trials for GI cancers. It represents a calculated synergy, merging Lonza's formidable manufacturing and platform technology with Antharis's specialized expertise in antibody engineering and target biology. The goal is to develop highly differentiated ADCs capable of tackling multi-drug resistance and improving survival rates in a patient population with profound unmet needs.

The Next Generation of "Smart Bombs"

Antibody-drug conjugates are often described as biological “smart bombs,” engineered to deliver potent cytotoxic agents directly to cancer cells while sparing healthy tissue. A conventional ADC links a single type of chemotherapy payload to a monoclonal antibody that seeks out a specific antigen on the tumor's surface. While this approach has produced several blockbuster drugs, its efficacy can be limited by tumor heterogeneity—the diverse mix of cells within a single tumor—and the cancer's ability to develop resistance to the single payload.

This is where dual-payload ADC technology represents a strategic leap forward. By attaching two distinct cytotoxic payloads to a single antibody, these next-generation ADCs can attack cancer cells through multiple mechanisms simultaneously. This multi-pronged assault is designed to be more effective against heterogeneous tumors and significantly reduces the likelihood of cancer cells developing resistance. If a cell learns to evade one payload, the second, with a different mechanism of action, can still deliver a fatal blow.

Lonza's platform, which includes its proprietary GlycoConnect® site-specific conjugation and HydraSpace® polar spacer technologies, provides the sophisticated architecture needed to build these complex molecules. It allows for precise control over the drug-to-antibody ratio and the relative amounts of each payload, which is critical for optimizing both efficacy and safety. According to industry experts, this level of precision engineering is essential to creating ADCs with a wider therapeutic window and a more predictable clinical profile.

A Strategic Alliance to Tackle a Formidable Foe

The strategic rationale behind the Lonza-Antharis partnership is underscored by the grim statistics of gastrointestinal cancers. Encompassing malignancies of the stomach, colon, pancreas, and liver, GI cancers account for roughly one in four cancer cases and one in three cancer-related deaths globally. Progress in treating many of these diseases, particularly advanced pancreatic and stomach cancers, has been slow, with high rates of recurrence and poor long-term survival.

Under the terms of the agreement, Antharis will drive the research, clinical development, and commercialization of the new ADCs. Lonza will act as a crucial supply chain partner, manufacturing the proprietary payload and linker components, and will receive upfront payments, potential milestone payments, and royalties on net sales. This financial structure is a classic risk-sharing model in the biopharmaceutical industry. It allows the smaller, innovation-focused Antharis to leverage a world-class technology platform without prohibitive upfront costs, while Lonza secures a long-term stake in the potential success of a promising clinical pipeline.

Raphael Ribeiro Pinaud, CEO of Antharis Therapeutics, framed the deal as a pivotal moment for his company. "This collaboration represents a major strategic milestone for Antharis," he stated. "By combining Lonza's clinically validated ADC technology platform with Antharis' antibody engineering, target biology and translational expertise, we are well positioned to advance next-generation dual-payload ADCs. We believe this collaboration creates a powerful and highly differentiated approach to oncology drug development."

Charting a New Course in Oncology Development

This partnership highlights a key trend in modern drug development: the strategic convergence of specialized innovators and established platform providers. Antharis Therapeutics has cultivated a reputation for its deep expertise in identifying novel cancer targets and engineering antibodies against them. With a lead program ready for the clinic, this agreement provides the technological backbone needed to accelerate its development.

For Lonza, the deal reinforces its position not just as a contract development and manufacturing organization (CDMO), but as an integral technology partner in the ADC space. Following its strategic acquisition of Synaffix, Lonza has curated a comprehensive, end-to-end offering that enables partners to move seamlessly from concept to clinical manufacturing. This "one-stop-shop" model is increasingly attractive to biotech companies looking to de-risk and streamline the complex ADC development process.

Jan Vertommen, Vice President of Commercial Development at Lonza, commented on the synergy. "This licensing agreement highlights an exciting new innovation based on Lonza's proprietary dual payload technology. We are excited to combine our platform with Antharis' deep expertise in antibody engineering and target biology to evaluate its potential to advance next generation ADCs."

The collaboration is a testament to the growing industry consensus that multi-warhead strategies are the future of ADC therapy. By combining distinct mechanisms of action, these advanced conjugates promise a step-change in efficacy, particularly against the drug-resistant and heterogeneous tumors that characterize many GI cancers.

A New Horizon for Patient Care

Beyond the corporate strategy and scientific innovation, the ultimate promise of this collaboration lies in its potential to change patient outcomes. For individuals battling gastrointestinal cancers, the development of dual-payload ADCs offers a tangible source of hope. These therapies hold the potential to produce deeper, more durable responses than current standards of care, potentially extending survival and improving quality of life.

By designing therapies that can overcome the biological defenses of the most resilient cancer cells, Lonza and Antharis are aiming to turn the tide against some of the most challenging malignancies. As Antharis prepares to advance its lead candidate into the clinic, the oncology community will be watching closely, hopeful that this strategic alliance will deliver a powerful new weapon in the fight against cancer.