aTyr Pharma, Inc. (NASDAQ:LIFE) Q3 2022 Earnings Call Transcript

Yale Jen: Okay, great. Thanks. Appreciate that and congrats on some good decision made so far.

Sanjay Shukla: Thank you.

Operator: One moment. Our next question will be from Sean Kim of Jones Trading. Your line is open.

Sean Kim: Yeah. Hi. Thank you for taking my questions. And I apologize if I’m repeating questions that have been asked previously, but for the Phase 3 efzofitimod trial, can you kind of remind me what the statistical plan has been including the statistical powering? Also, how much of a separation from placebo has been baked into that kind of calculation?

Sanjay Shukla: Sure. Happy to do that. So our trial is powered. We have 264 patients, 3 dose arms, there’s a 5 milligram, a 3 milligram and a placebo arm, and each arm is 88 patients. We powered this trial over 90% — 92% to be exact for either the 3 milligram or the 5 milligram dose of showing statistical superiority to placebo. So we have essentially two shots on goal with either of these two at a much higher clip typically you want to power these studies at least 80%. We’ve actually done them both — with both of these doses at over 90%. In layman’s terms, what are we trying to show in steroid reduction, an absolute reduction of somewhere between 2.5 milligrams to 3 milligrams difference is, in our eyes meaningful. In the eyes of experts, for example, if you have a patient coming in at 10 milligrams and getting on EFZO, gets them down to 7.5 that’s meaningful benefit.

It may not seem like a lot for us, but every day, we’re moving 2 milligrams to 3 milligrams of prednisone, this adds up. Removing that decreases the overall cumulative burden and over the course of six, nine, 12 months, this is going to help you with cardiovascular, metabolic, neuro effects of what steroids do. So hope that provides a little bit of color there. Very, very well powered. I’m a little bit very particular about statistics having a background in that. So I think that’s something that we wanted to overpower if you will and we have two shots on goal to essentially show about that 2.5 milligram and 3 milligram difference.

Sean Kim: Okay. That’s very helpful. Thank you. And I guess just one follow-up question on that is, you have three arms with 3 mg and 5 mg and placebo. Just curious what’s the rationale behind going after two different doses versus just going after higher dose that might provide improved efficacy and maybe increased ?

Sanjay Shukla: Yeah. So this was actually an initial approach in dialogue we had at the end of Phase 2 meeting because our last data set showed that 5 was rather outstanding, but even the agency pointed out that 3 milligram are actually quite good. We showed improvement in symptoms. We showed lung function improvement and we showed a reduction of about 49% in the 3 milligram arm. The view was it would be good to also interrogate that dose because it provides a backup to, if 5 milligram, for example, we see any emerging toxicity. Now we haven’t seen any toxicity with any of our high doses — any of our doses from the last trial. But let’s also understand that, that data set had less than 10 patients in arm. Now we’re getting up to close to 90 patients in arm.