CD22

If it's not 40%, if it's much lower, there's likely to be a problem with the trial.

So epituzumab, which is anti-CD22 antibodies, classic example, phase two looked good.

There were several doses where it seemed to meet its primary endpoints.

But what the company forgot about was the fact that the placebo response rate was 20%.

And they found a big change in the expression of a receptor that binds to glycans.

And it's a receptor called CD22.

Uh, we also-- It has another name called Siglec-II, which is sialic acid-binding immunoglobulin-like lectin [chuckles] II, okay? Anyways, point is that my lab had been studying that family of receptors because of their role in cancer immune suppression.

Yeah.

That's right.

Right.

And CD22 is a brake type of receptor.

It's inhibitory when it gets engaged with its ligands.

One way to improve.

The second way is to say, "Okay, CD19 was the ideal target, but we have other target possible." The classical one is CD22 for B-ALL, which is expressed in nearly all B-ALL diagnosis.

So there have been trials for CD22, which have shown some inconvenience, particularly so-called macrophage activated syndrome or HLH.

Also, it seems that there is a downregulation of this target.

So people are thinking, let's imagine that instead of targeting only one antigen and with a clonal escape when the target disappear, let's imagine to target two at the same time.