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Latent Space · 3 min · Oct 14, 2026

Leash reached mouse PK/PD in six months

IQ

Ian Quigley

Co-founder & CEO, Leash Bio

  • BA

    Brandon AndersonHost · Atomic AI

    Co-hosts Latent Space's AI for Science; builds AI for RNA drug discovery.

  • RH

    RJ HonickyHost

About this segment

Ian says selected library hits reached mouse PK/PD in six months with few medicinal-chemistry cycles. The team tracked cytokine levels for an inflammation compound.

From “From Wet Lab to RL Env: 10,000 Drug-Discovery Campaigns in a Weekend — Ian Quigley, Leash Bio”, Oct 14, 2026. Watch the full episode

“for what it's worth, we've gone directly from chemical library hits to good PKPD in a mouse in six months with a very small number of MedChem cycles.”
IQIan Quigleyat 1:28:41 · Latent Space1:28:41

Takeaways

  1. Selected hits reached mouse PK/PD in six months.
  2. Library design included drug-likeness and ADMET predictions.
  3. The mouse study tracked cytokines for an inflammation compound.
Watch 2:41 from 1:28:26

In this episode

Full episode
  1. 46:24Public chemistry data can encode the chemist, not the chemistry5:49
  2. 28:15A four-billion-measurement contest found a generalization gap7:24
  3. 1:17:04Measured chemical landscapes let agents run thousands of campaigns7:07
  4. 1:03:18Protein mutations create experimental negatives for binders6:12
  5. 1:42:49Lumacaftor-like hits can flag misfolded proteins3:51
  6. 9:14Multiple barcodes expose DNA-binding false positives5:20

  7. 1:28:26Leash reached mouse PK/PD in six months2:41

  8. 15:24Screening many proteins reveals quirks in each library3:52Up next

Transcript

Transcribed by machine (Whisper) from the episode’s audio, so a word may be off here and there.

  1. 1:28:32

    I'm more worried about building block diversity. And there's sources for that. What about admit properties in general? You've been focusing very much on binding. We have, yeah. So of projects that we've done, trying to look at reasonable admit and PKPD properties, for what it's worth, we've gone directly from chemical library hits to good PKPD in a mouse in six months with a very small number of MedChem cycles.

  2. 1:28:55

    So at least the chemical material that we currently have, or at least those few series that we did that for, they turned out pretty good in our hands. I guess we will continue to see how that modeling looks. And also, of course, we want to do more of these ad-net target models and then think about how to incorporate other types of more emergent models along with our designs. Was that speed driven by your ability to create custom local combinatorial libraries?

  3. 1:29:18

    Or was that speed driven? What allowed you to get there in six months? It's like... So when we designed this chemical libraries at the beginning, we very much optimized that space for drug likeness. And so we think that's part of it is that was like a really good starting point. You know, when we do our chemical library designs, we have this kind of like Thompson sampling level approach where we come up with an optimization function.

  4. 1:29:40

    You say, okay, well, I want the libraries to have these properties. And so some of those properties are going to be I want to bind these things. I want to avoid these things. And then some of these properties are going to be, oh, there's other ADMET model approaches that you can use to make predictions about how your chemical material might turn out. And so you put that as part of the optimization function.

  5. 1:29:56

    And then what you do is you say, okay, of all the chemicals that I could make given my geometry, I don't want to make that many. I want to make a smaller number. And so you basically set up and generate a bunch of synthetic libraries and then you score them on this optimization function. And so we did that with this library and the starting material looked pretty good. So I'm sure that we'll continue to do that.

  6. 1:30:15

    Along those same lines, has anything that you've done like made it to so it made it to animals yeah so PKPD in the mouse is that's yeah so what that means is can you dose the mouse with the thing and then see how it gets into the mouse's body and tissues so PKPD is pharmacokinetics pharmacodynamics meaning how does the body move the drug through the or how does the metabolism move the drug through the body yeah and then are there biomarkers of the drug's intended activity.

  7. 1:30:47

    And so what that means here is this is like a drug, this is a compound we're working on for only the inflammation. And so we were following cytokine levels in mouse blood and they did what we wanted them to do and expected them to do based on the targets of the drug. So Sean likes to ask, when money? I want to ask, when people?