Mirum Pharmaceuticals (MIRM) Q4 FY25 earnings call: guidance and Q&A

How is Mirum thinking about pricing Volixibat, especially for PSC where there are no approved therapies, compared to PBC pricing benchmarks?

Mirum considers PPARs in PBC as a good planning benchmark but will make a final pricing decision closer to launch, especially given Volixibat's unique positioning in PSC with no approved therapies.

“The PPARs in PBC really are good planning benchmark to think about, but that's not -- certainly not our final guidance or decision on it. We'll take that as we have data in hand and are closer to launch to make the final decision.”

asked by James Condulis · answered by Christopher Peetz

Does the episodic nature of itch in PSC patients pose a risk to the Volixibat study, and how is the study designed to limit variability?

Management believes pruritus in PSC is often persistent, contrary to some KOL views, based on patient and advanced practitioner feedback. The VISTAS study enrolls patients with persistent pruritus and tracks response, ensuring the design addresses this significant symptom.

“What we find in market research that's more directed at patients and some of the advanced practitioners that maybe spend more time with patients is a different perspective on pruritus than what you get from some of the top KOLs who may actually just be seeing the patient episodically when there are other more complicated factors.”

asked by Joseph Thome · answered by Christopher Peetz

What are the key similarities and differences between the VISTAS and VANTAGE study designs, and should baseline pruritus scores for PSC be similar to PBC interim data?

Both studies focus on cholestatic pruritus, which Mirum is experienced in measuring. While PSC and PBC have different etiologies, the commonality is intrahepatic cholestasis and pruritus. Baseline pruritus scores are expected to be similar to the moderate-to-severe range seen in PBC interim data, as both studies select patients with this profile.

“I think probably the best guide in terms of what the baseline pruritus is, is if you look at the PBC interim and that shows significant pruritus, I mean, with -- clearly, within the range of moderate-to-severe pruritus for baseline. So I think that's kind of our expectation.”

asked by Johoon Kim · answered by Joanne M. Quan

What are the FDA's safety database requirements for Volixibat, and what does this mean for the timing of a potential NDA submission?

Mirum has confirmed safety database requirements with the FDA, acknowledging PSC is a smaller population. They expect the current VISTAS PSC study to provide a sufficient safety database for submission. An interaction with the FDA on the submission plan is expected after topline data, aiming for an NDA submission in H2 2026.

“We do expect that the current VISTAS PSC study has the sufficient safety database for the setting. So the idea is after our top line data, we'll have an interaction with FDA on the submission plan and think that we'll track to get it submitted in the second half of the year.”

asked by Jon Wolleben · answered by Christopher Peetz

How will a positive EXPAND readout translate to label expansion given it's a basket trial, and how well diagnosed are the additional settings for LIVMARLI?

The label expansion for EXPAND, being a basket trial, will likely be defined by exclusion, covering conditions not addressed by stand-alone studies. The pediatric settings targeted are highly symptomatic and well-diagnosed, with demand already existing due to compassionate use, suggesting a well-tracked patient population.

“The thinking around label -- indication statement in the label, as you point out, it has some nuance because it's a basket. It's really defined by exclusion, right?”

asked by Ryan Mcelroy · answered by Christopher Peetz

How is the HDV market expected to develop, and what is the anticipated R&D increase for HDV studies this year?

The HDV market is evolving, with no specifically labeled medicine in the U.S. currently, though Hepcludex is performing well in Europe and is under review in the U.S. Brelovitug is expected to be best-in-class due to its single-agent profile, impressive response rates (100% viral response at week 48), and attractive safety. R&D spend will increase by approximately $150 million in 2026 for Brelovitug, with half for CMC.

“In total related to Brelovitug, we anticipate roughly $150 million increase in R&D spend tied to this program with about half being CMC.”

asked by Rohit Bhasin · answered by Eric Bjerkholt