Amgen, Merck KGaA add to budding constellation of ADC deals amid the modality's meteoric rise

The pool of Big Pharmas competing to develop game-changing antibody-drug conjugates continues to grow, with the water now at a boil after two more sizable licensing pacts.

Amgen and Merck KGaA each entered the holiday weekend with separate collaborations aimed at developing the burgeoning cancer-targeting modality, with the deals' combined value eclipsing $2 billion. 

German Merck got the party started with an $830 million pact tapping Mersana Therapeutics, including $30 million in upfront cash in exchange for up to two targets. The deal, unveiled Thursday, lines up with Merck’s recent R&D ambitions, which include half of future product launches coming from external drug developers. 

Amgen followed up the news by disclosing a deal of its own on Friday, inking a potential $1.25 billion pact with LegoChem Biosciences for up to five ADC options. That deal provides further outside validation of LegoChem’s ConjuAll ADC platform, which the company touts as delivering enhanced specificity for cancer targets coupled with drug payload technology. The deal with Amgen pushes the cumulative value of LegoChem’s 12 licensing deals past $5 billion. 

The two deals added to the licensing money that flowed into the stockings of ADC-developing biotechs, after the U.S.-based Merck & Co. inked a partnership last week with Kelun that could total $9 billion or more. All told, these three ADC deals eclipse $11 billion in potential biobucks, should any identified candidates clear regulatory and clinical milestones. 

The announcements from Amgen and Merck KGaA also further validate antibody-drug conjugates as a whole, which are arguably the hottest new therapeutic ticket in pharma.

Their rise comes as the industry has looked to establish valiant competitors to the immuno-oncology behemoths and checkpoint inhibitors that have defined cancer therapies for the better part of the 2010s. ADC therapies merge a monoclonal antibody with a drug payload to reinvigorate the immune system's ability to fight cancer while treatment-bombing the disease directly. 

The potential of ADCs is not a new revelation, but the therapies caught fire this summer after AstraZeneca and Daiichi Sankyo detailed stunning data of their approved HER-2-directed breast cancer treatment, Enhertu, at the American Society of Clinical Oncology annual meeting.

The drug-conjugate field is now continuing to bud, and beyond combinations with antibodies. Following up on the Kelun deal, Merck & Co. tacked on a peptide-conjugate deal, revealing a multi-target licensing extension with PeptiDream Monday worth up to $2.1 billion. The number of targets on the table was not disclosed, but Merck will have the opportunity to exclusively pick up whatever candidates it elects to develop. The deal builds on an existing pact between Merck and PeptiDream that was first inked in April 2015.