X4 Pharmaceuticals, Inc. (NASDAQ:XFOR) Q3 2023 Earnings Call Transcript

Paula Ragan: No, I think what we’re doing for the Phase 2, of course, is all comers, because there’s two questions we’re trying to answer, obviously making sure that our Phase 3 study design is robustly incorporating any responses that we’re seeing. And then secondly, there’s the longer term question around GCSF. So both of those questions need to be answered. That’s why we are including a diverse population with no prespecified numbers in any of those categories.

Andy Fleszar: That makes sense. And then one final question from us. From your market research, can you speak about what level of GCF reduction is clinically meaningful to patients and prescribers? Obviously, more reduction is better, but any color that you can provide on what success might look like would be helpful.

Paula Ragan: That’s an excellent question. And our answer is, come to the ASH poster, because we’ll be actually providing some very meaningful market research around that exact question.

Andy Fleszar: Sounds great. We look forward to seeing you there. Thank you.

Paula Ragan: Thank you.

Operator: Thank you. Next question comes from the line of Kristen Kluska with Cantor Fitzgerald. Please go ahead.

Kristen Kluska: Hi. Good morning, everyone. Thanks for taking the question. When I look at your finalized Phase 3 CN study design, in a lot of ways, as you mentioned, it really does mirror what the trial looked like for WHIM, which, of course, was successful. So can you talk about how you think that gives you the confidence in this particular study and any differences we should really be thinking about related to the mechanism in these subset of patients versus WHIM?

Christophe Arbet-Engels: No. So we have worked with one of our consultants, Professor Tom Fleming from the FDA, in designing that study very closely with him. We are confident that we have the power for our primary endpoint to be achieved, and we have the right sample size. We have two populations that we’re going to be included in that study, which is the monotherapy and the patients on GCSF. And because it’s a randomized, double-blind controlled trial versus placebo, we will be able to establish the effectiveness, the efficacy of mavorixafor. We also incorporated in that study the requirements from and the feedback from the FDA that we received. And so we believe we have all the elements to recruit and see positive data in this Phase 3 study.

Paula Ragan: And maybe just to remind folks, in the WHIM Phase 3, we saw about a 60% reduction across those patient populations. We actually took a fairly conservative approach, even reducing that, to plan for the stats on the Phase 3, which is why we feel very confident.

Kristen Kluska: Okay, thanks for that. And it’s nice to see the uptick in enrollment in this update. Can you maybe talk about what you think? Some of the factors are that it was originally slower than expected. Now that you’ve seen this uptick, so were it things like seasonality? And again, how this also helps for planning for Phase 3. Thanks again.

Paula Ragan: Yes, sure. I think trial enrollment is a challenge for every biotech out there, especially in a new field such as chronic neutropenia. But I think what we just learned is the summer is tough for some of the younger patients. We actually have fairly sick patients in this trial, but they certainly wanted to have some downtime as is expected. The trial enrollments picked up nicely. I mean, more importantly, Phase 3s are very different from Phase 2s. They’re a very heavy operational lift. You want to create a large pool of patients waiting that are co-localized with your sites. We actually have a very nice start to that with quite a robust patient pool already identified to the sites that are coming on board. So we look forward to certainly hitting that 12 month enrollment with high confidence.

Operator: Are you done with the question, Ms. Kluska?

Kristen Kluska: Yes. Thank you.

Operator: Thank you. Next question comes from the line of Swayampakula Ramakanth with H.C. Wainwright. Please go ahead.