Merck KGaA has signed an exclusive worldwide license agreement with Denmark's Symphogen to get access to a cancer drug that is being seen as a successor to the German group's big-selling Erbitux.

The drug in question is Sym004, an investigational antibody mixture targeting the epidermal growth factor receptor (EGFR). Specifically, it is comprised of two antibodies that are not only designed to block ligand binding, receptor activation and downstream signalling "but are also thought to elicit removal of the EGFR receptors from the cancer cell surface by inducing EGFR internalisation and degradation".

Sym004 is currently being evaluated in a Phase I/II trial for patients with advanced KRAS wild-type metastatic colorectal cancer (mCRC) who have previously progressed on treatment with standard chemotherapy and a marketed anti-EGFR monoclonal antibody. Also a Phase II trial in patients with squamous cell carcinoma of the head and neck who have failed anti-EGFR-based therapy is ongoing.

Cashwise, Symphogen will receive an upfront fee of 20 million euros. The Copenhagen-headquartered group is also eligible to receive up to 225 million euros for clinical development and regulatory payments and 250 million euros in potential combined sales performance milestones and royalties.

Erbitux (cetuximab) is currently indicated in Europe, where Merck holds the rights, for EGFR-expressing mCRC, including treatment of the KRAS wild-type mutation in those patients. Also approved for head and neck cancer, the drug (partnered with Eli Lilly and Bristol-Myers Squibb) brought in 226 million euros to Merck's coffers in the second quarter, up 7.1%.

Susan Jane Herbert, head of global business development and strategy for the firm's Merck Serono division, said that Sym004 "further strengthens our early development pipeline by adding a product that is thought to act via a proposed synergistic mechanism of action not previously studied". More specifically, she added that "it has the potential to become a key asset complementing our already-highly successful Erbitux franchise".

Kirsten Drejer, Symphogen's chief executive, added that Merck is uniquely well positioned to develop Sym004 based on its deep knowledge of the EGFR area". She added that “this transaction further validates the antibody mixture approach as a highly attractive option".

Symphogen’s most advanced product is rozrolimupab (Sym001), which has just completed Phase II trials as a treatment for immune thrombocytopenia. The privately-owned firm raised 100 million euros in equity capital in January 2011.