3D Rendering of Antibody Drug Conjugate Molecules
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China-headquartered MediLink Therapeutics has entered into a deal with BioNTech for development of a next-generation antibody-drug conjugate candidate (ADC) against Human Epidermal Growth Factor Receptor 3 (HER3). With an upfront payment of $70M and plenty of additional development, regulatory, and commercial milestone payments, the deal could be worth over $1 billion.

ADCs have been a piping hot commodity this year, netting several deals worth potentially $1B or more. In early April, BioNTech started its foray into ADCs through a deal with Duality Biologics worth up to $1.5B. Soon after,  Bristol Myers Squibb signed a deal worth up to $1B for Tubulis to use the biotech’s “PS conjugation platform” to develop ADCs against solid tumors. In May, Eisai inked a clinical trial collaboration worth up to $2B with Bliss Biopharmaceutical. This is a Phase I/II for BB-1701, which has an eribulin-payload that targets Human Epidermal Growth Factor Receptor 2 (HER2).

But the biggest deal of all was Pfizer’s $43B acquisition of ADC specialist Seagen early on, in March. The acquisition of Seagen (formerly Seattle Genetics) doubled Pfizer’s early-stage oncology clinical pipeline. Seagen is an outstanding pioneer in ADCs—four of the more than twelve FDA-approved and marketed ADCs have been developed using its technology.

The leader in this field is currently Daiichi Sankyo, which has several ADCs in development. But the company also has the blockbuster Enhertu, which it developed with AstraZeneca. That drug, which targets a new class of HER-2 low tumors, rebooted the ADC field and led to a surge in Daiichi Sankyo oncology sales.

The global market for ADCs is already worth several billion dollars, and is expected to grow considerably over the next decade. There are over 100 of these drugs in clinical trials.

Under this newly announced agreement, MediLink will grant BioNTech exclusive global rights for the development, manufacturing, and commercialization of one of MediLink’s ADC assets. The deal excludes Mainland China, Hong Kong Special Administrative Region, and Macau Special Administrative Region.

MediLink’s drug comes with a twist, as it targets a less well-known receptor—HER3. But this receptor is overexpressed in various cancer types, such as non-small cell lung cancer and breast cancer, and is closely associated with tumor metastasis and disease progression. HER3 expression is also upregulated after frontline drug therapy, making it an attractive target for cancer treatment.

The company says its ADC candidate has demonstrated efficacy and safety in various preclinical tumor models and preliminary clinical data further supports its promise.

The biotech has built a differentiated proprietary Tumor Microenviroment Activable LINker-payload (TMALIN) ADC technology platform, that it says can generate homogeneous ADCs and further improve the therapeutic window in treatment of solid tumors. TMALIN uses a dual cleavage mechanism both intracellularly and extracellularly, taking advantage of the tumor microenvironment and traditional lysosomes.

In its recent press release, MediLink said: “TMALIN offers high hydrophilicity, high homogeneity DAR value, high in vitro & in vivo stability, and tumor accumulation characteristics. In multiple CDX and PDX models, as well as tox studies, it has demonstrated a wider therapeutic window compared to existing ADC technologies.”

The company added that several ADC products based on this platform have entered clinical trials.

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