Mirum's Q2 2026 Call: PSC Trial Uncertainty and Shifting NDA Timelines Clash

Date of Call: Aug 5, 2026

Financials Results

• Revenue: $176M in net product sales, compared to $128M in Q2 prior year
• Gross Margin: Cash contribution margin in the high 50s percent, a ~5 percentage point improvement over the prior year

Guidance:

• Full-year 2026 net product sales guidance increased to $680 to $700 million.
• NDA submission for velixibat for PSC targeting first half of 2027.
• Potential BLA submission for belovatug in PBC in first half of 2027.
• EXPAND study top-line data for Livmarli expected in Q4 2026.
• Potential U.S. launch of zolurcertib for FOP in Q4 2026.

Business Commentary:

Commercial Performance and Revenue Growth:

• Merum Pharmaceuticals reported net product sales of $176 million for Q2 2026, up from $128 million in Q2 2025.
• The increase was driven by strong demand across the portfolio, particularly from Livmarly and bile acid medicines, leading to an increased full-year 2026 net product sales guidance of $680 to $700 million.

Pipeline Progress and Regulatory Developments:

• The VISTA study for velixibat in pruritus due to PSC met its primary endpoint, leading to a Breakthrough Therapy Designation from the FDA.
• Despite the positive results, the FDA recommended a phase three study, which is seen as an opportunity for further engagement to supplement the NDA submission, with a new target submission timing for the first half of 2027.

Financial Strength and Strategic Positioning:

• The company improved its capital structure with the issuance of $690 million in convertible notes, adding $197 million in cash and reducing interest expense.
• This financial strengthening provides greater capacity for investment in potential launches, clinical development, and business development, supporting the advancement of multiple clinical programs.

Rare Genetic Disease Expansion:

• The addition of zolurcertib for FOP to the rare genetic business is expected to launch in Q4 2026, with an NDA progressing towards a September PDUFA date.
• The convenience of oral dosing and strong efficacy data from the pivotal Phase II study support its potential as an attractive treatment option for FOP patients.

Sentiment Analysis:

Overall Tone: Positive

• CEO stated 'This quarter demonstrates continued progress with strong commercial execution' and 'I'm proud of the team's progress and the promise of our current medicines and pipeline, and I'm excited about what lies ahead.' Commercial performance was strong, driving increased sales guidance and funding pipeline milestones.

Q&A:

• Question from Ryan Deschner (Raymond James): Curious what your overall take is on the potential read-through from the BOLD study evaluating otavixibat in patients with biliary atresia.
  Response: The BOLD study is different from EXPAND; BOLD looks at acute bilirubin reduction, while EXPAND evaluates pruritus in older patients, with no direct read-through.

• Question from Ryan Deschner (Raymond James): What key topics do you anticipate addressing with FDA in future discussions on PSC?
  Response: Need to get the new FDA team up to speed on VISTA study design, history, and data package through iterative discussions.

• Question from Gavin Clark Gardner (Evercore ISI): What was the FDA's rationale for recommending an additional phase three for velixibat in PSC?
  Response: FDA comments were general on efficacy and safety (IBD, GI, liver safety), but VISTA data already addresses these; likely due to team unfamiliarity with the study.

• Question from Gavin Clark Gardner (Evercore ISI): Is this a new FDA team? What precedents support approval based on a Phase 2b study?
  Response: Team involvement unclear; precedent exists with other IBAT approvals (e.g., Ocaliva, Lennox) based on shorter placebo-controlled studies similar to VISTA.

• Question from Rohit (Morgan Stanley): Based on FDA conversation, any read-through to the PBC Vantage study? Commercial prep status for FOP?
  Response: Vantage has clear FDA feedback to be a pivotal study; PBC commercial prep is on track with launch readiness progressing well.

• Question from Brian Scorney (Baird): Can you refresh on FDA's specific issues with VISTA and team members involved?
  Response: FDA team may have changed; discussion focused on efficacy (addressed by VISTA) and safety; breakthrough designation post-meeting is a positive sign.

• Question from Brian Scorney (Baird): Any commentary on the late cycle review meeting for zolurcertib and confidence in labeling?
  Response: Meeting went very well, application progressing towards PDUFA date; full systems go for potential Q4 launch.

• Question from Kalpit Patel (Wolf Research): Has there been dialogue on a post-approval confirmatory study instead of a phase three?
  Response: No specific post-approval study discussion; expect a post-marketing registry/monitoring as typical for full approval, not accelerated pathway.

• Question from James Condoles (Stifle): Is a phase three on the table for PSC, or can it be resolved through data iteration?
  Response: No clear gain from another study given VISTA's robust results; confidence in working through with FDA to move forward.

• Question from Lisa Walter (RBC): Could the NDA delay lead to more business development? Is pruritus still an approvable endpoint?
  Response: Pruritus is definitely approvable; BD remains opportunistic and active, not directly related to the delay.

• Question from Joe Schwartz (Leerink Partners): Hypothetically, could a PBC NDA strengthen the PSC regulatory package if FDA doesn't budge?
  Response: In a hypothetical, a large PBC study could add weight, but the base plan is to submit PSC NDA first.

• Question from Joe Schwartz (Leerink Partners): Did any baseline characteristics correlate with better response to Brilovitug?
  Response: No obvious correlations; response is broad-based across all patient groups.

• Question from Jessica Fai (J.P. Morgan): What can supplement the VISTA trial, and what gives confidence in a first half 2027 filing timeline?
  Response: Can add more safety data; timing confidence based on experience with prior applications and room for FDA iteration.

• Question from Joseph Tomey (TD Cowen): When will you provide next steps on filing progress? Did the new FDA group provide PBC feedback?
  Response: Updates only on material progress; PBC feedback via written correspondence, not known if same team.

• Question from John Volubin (Citizen): What does the iterative dialogue with FDA look like?
  Response: Breakthrough designation allows more frequent informal and formal meetings; sequence depends on dialogue progress.

• Question from Ramakant Swayampukula (H.C. Wainwright): Planning any changes for PBC indication? Risk of refuse to file if submitted in H1 2027? Expected adcom?
  Response: PBC approach is on good course with recent adjustments; interactive dialogue aims to mitigate RTF risks; adcom could be helpful given therapy's impact.

Contradiction Point 1

FDA Regulatory Pathway for PSC (Volixibat)

Contradiction on whether a Phase 3 trial is required or can be resolved through data iteration, impacting regulatory strategy and timeline.

Kalpit Patel (Wolf Research) - Kalpit Patel (Wolf Research)

2026Q2: The company does not see what would be gained from a Phase 3 given VISTA's large size, clear results, and comprehensive safety data. - [Chris Peets](CEO)

Has the FDA discussed a post-approval confirmatory study instead of a Phase 3 trial, or should we assume a Phase 3 is required? - Gavin Clark Gardner (Evercore ISI)

2026Q2: The FDA's rationale was not clear. General comments were made on efficacy... and safety. - [Chris Peets](CEO)

Contradiction Point 2

Nature of FDA Review Team Involvement

Contradiction on whether the new FDA team was involved in prior interactions (e.g., PBC), affecting transparency and trust in the review process.

What are your key takeaways from the earnings report, Joseph Tomey (TD Cowen)? - Joseph Tomey (TD Cowen)

2026Q2: It is difficult to know who is behind written correspondence. The pre-NDA meeting was held in person. - [Chris Peetz](CEO)

Was the new FDA team involved in PBC feedback? - Gavin Clark-Gartner (Evercore ISI)

2026Q2: The PBC feedback came via written correspondence; it's unclear if it's the same team, but recent. - [Chris Peetz](CEO)

Contradiction Point 3

Commercial Preparation and Sales Guidance for FOP (Zoluricerib)

Contradiction on whether FOP revenue is included in the 2026 sales guidance, affecting financial forecasting and investor expectations.

Joseph Tomey (TD Cowen), what are your key concerns? - Joseph Tomey (TD Cowen)

2026Q2: The $680-$700M 2026 guidance does not include FOP. - [Peter Radovich](COO)

Is FOP included in the updated 2026 sales guidance? - Rohit (Morgan Stanley)

2026Q2: Commercial preparation for the FOP launch is going well... The NDA review is progressing, with the potential for a Q4 launch. - [Peter Radovich](COO)

Contradiction Point 4

FDA Team Familiarity and Involvement

Contradiction on whether the FDA review team was involved or familiar with prior discussions, impacting the perceived continuity and stability of regulatory engagement.

Brian Scorney (Baird) - Brian Scorney (Baird)

2026Q2: Office leadership may have changed, and leadership was not in the meeting. The Breakthrough Therapy Designation post-meeting is a positive nod. - [Chris Peets](CEO)

What were the FDA's issues with VISTA, and was the review team familiar with the study? - John Wolinben (Citizens)

2026Q1: Mirum had full access to clinical data, regulatory correspondence, and the NDA during its review... - [Chris Peetz](CEO)

Contradiction Point 5

NDA Submission Timeline for PSC

Guidance on when the PSC NDA might be submitted has shifted significantly, affecting strategic planning and market expectations.

James Condoles (Stifle) - James Condoles (Stifle)

2026Q2: The first-half 2027 timeline is based on experience with similar applications and allows room for a couple of iterative FDA meetings. - [Chris Peets](CEO)

What are the plans for advancing PSC (Phase 3 or data iteration) and what informs confidence in the first-half 2027 NDA submission? - Jonathan Wolleben (Citizens)

20260226-2025 Q4: The goal to submit an NDA in the second half of 2026. - [Christopher Peetz](CEO)