Just As Rahway Adds ADC Prospects, With Japan's Daiichi -- It Prunes Two, With China's Kelun...

It all makes good sense, to be certain. Merck will, at about 2035, need successor candidates to the juggernaut of pembrolizumab. And so it has time, and cash, on its side. Focusing on the most probable winners makes very solid bioscience- and thus business- sense.[My prior December 2022 backgrounder on the relationship, here.]

While I think the pressers have tended to overstate the actual probable size of the Daiichi-Sankyo ADC deal expansion, it is certainly true that that approach is cheaper, all in, than buying Seagen outright (at ~$44 billion -- the tab Pfizer will now pay, just to get in the game here).

Even so, as ever, being disciplined requires a hard look at each interim point along the way to a first clinical trial. And two of Kelun's ADCs seem to be well-behind those of Daiichi's. Here's that story, from Fierce BioScience now:

. . .Merck is pruning its pipeline of antibody-drug conjugates. Days after the Big Pharma paid $4 billion for three Daiichi Sankyo assets, Kelun-Biotech has revealed the Big Pharma has decided (PDF) to pass over two of its preclinical ADCs.

China’s Kelun has played a starring role in Merck’s drive into ADCs over the past 18 months. The companies penned three pacts in short order, giving Merck rights to a trio of clinical candidates against targets such as TROP2 and CLDN18.2, as well as up to six preclinical prospects. Now, having quickly built a pipeline of nine partnered programs, Merck has told Kelun it is backing out of two of the preclinical projects.

Merck is terminating its license to one preclinical ADC and turning down an option to pick up a second preclinical program. The Big Pharma told Kelun it remains committed to the broader ADC collaboration and plans to “rapidly advance the clinical development program” for the TROP2-directed MK-2870. . . .

Now you know -- and onward (back to lobbyists, this afternoon!). . . smiling. Ever, smiling.

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