MIRM · Mirum Pharmaceuticals, Inc.

The thesis

Mirum Pharmaceuticals beat third-quarter (Q3) sales estimates and raised its 2026 sales guide to $715–720M on 3 November 2026, so existing medicines now carry more of the case while spending climbs. The AZURE-4 hepatitis delta result, guided for Q4 2026, settles whether brelovitug reaches a filing in the first half of 2027.

Q3 net product sales were $185.7M, up from $133.0M a year earlier, against a $178.1M estimate reported by Benzinga. The new guide replaces $680–700M and sits above the $698.1M estimate Benzinga cited. The shares closed at $93.54 on 5 November 2026, up from $85.81 on 28 October 2026 and 27.2% below the 52-week high close of $128.57.

The narrative is maturing: the September and October approval and trial wins are well known, and MarketBeat counted 14 positive analyst ratings against one negative on 5 November 2026. The AZURE-4 result and the first Atebrioz sales figure are the remaining unknowns.

Bullish and bearish views on Mirum Pharmaceuticals, Inc.

The bull case on Mirum Pharmaceuticals, Inc. (MIRM), in brief: Sales and guidance both moved up. The bear case: Costs are growing faster than sales.

Bull case

• Sales and guidance both moved up. LIVMARLI sales were $133.4M in Q3, up 45% year over year, and bile acid medicines were $52.3M, up 28% (Mirum 8-K, 3 November 2026). Nine-month net product sales reached $521.8M, against $372.4M a year earlier.
• Late-stage programs keep resolving well. The FDA approved Atebrioz (zilurgisertib) for fibrodysplasia ossificans progressiva (FOP) on 25 September 2026. AZURE-1 met its primary endpoint on 28 September 2026, with 56% and 45% responses on the two doses against none on delayed treatment, and EXPAND met its primary endpoint on 12 October 2026.
• Filings are stacking up for 2027. Mirum's 3 November 2026 release plans a brelovitug biologics license application (BLA), subject to AZURE-4, plus a LIVMARLI EXPAND supplemental application and a primary sclerosing cholangitis filing for volixibat, all in the first half of 2027. CEO Chris Peetz described "five potential upcoming approvals and label expansions."
• Most targets rose after the report. Citizens raised its target to $167 from $144, Cantor Fitzgerald to $160 from $155 and HC Wainwright to $202 from $200, all on 4 November 2026. RBC reiterated $155 the same day, and MarketBeat listed an average target of $154.94 on 5 November 2026.

Bear case

• Costs are growing faster than sales. Q3 research and development (R&D) was $107.9M, up from $43.0M a year earlier, and selling, general and administrative expense (SG&A) was $88.9M, up from $61.9M. The operating result swung to a $59.7M loss from $2.6M income (Mirum 8-K, 3 November 2026).
• Loss per share missed estimates. Diluted loss was $(0.87) against a $(0.51) estimate reported by Benzinga, and basic loss was $(0.62). The 10-Q shows the diluted figure removes a $16.5M gain on an indemnification holdback, which also flattered the $40.8M net loss.
• Cash is falling. Cash and investments were $500.5M on 30 September 2026, down from $561.3M on 30 June 2026, and a $25.0M Atebrioz approval milestone was paid in October (10-Q). Operations used $277.3M in the first nine months, against $49.8M generated a year earlier.
• The 10-Q lists 6,826,045 shares issuable on conversion, against 65,282,044 outstanding on 30 October 2026.
• Atebrioz has no reported sales yet. The Q3 release gave no Atebrioz figure, so the first read should come with Q4 results. It is the third FOP therapy after Sohonos (16 August 2023) and Pasatru (19 August 2026), per the FDA, and Mirum owes Incyte mid-to-high single-digit royalties (10-Q).
• Insiders sold and one target fell. MarketBeat reported that CEO Peetz sold 20,000 shares at $90.00 on 4 November 2026 under a pre-arranged 10b5-1 plan, and that insiders sold 116,659 shares in the prior 90 days. Leerink cut its target to $140 from $154 on 5 November 2026 while keeping an Outperform rating.

Price setup

The shares closed at $93.54 on 5 November 2026, down 5.2% over three months. MarketBeat reported an $87.03 open on 4 November 2026 and a $3.43 fall on 5 November 2026, so the report produced a rise that partly reversed within two sessions.

MarketBeat listed the 50-day moving average at $89.51 and the 200-day at $98.44 on 5 November 2026, which places the close between them. The 14-day relative strength index was 70.7, a reading usually taken as stretched in the short term. Earlier closes of $82.93 on 2 October 2026 and $82.39 on 15 October 2026 mark the October low area, and the $75 level in the invalidation condition sits below both.

Observable crowding is modest: the signs are the relative strength reading and insider sales into the post-report rise. No earnings date falls in the next 30 days, while AZURE-4 could arrive at any point before year-end.

Catalysts, next 30 days

• 8 November 2026: Full AZURE-1 results and Phase 2b 48-week brelovitug results at The Liver Meeting, the American Association for the Study of Liver Diseases conference (Mirum 8-K, 3 November 2026). Durability and safety detail come into view ahead of AZURE-4.
• ~31 December 2026, est.: AZURE-4 Phase 3 topline, guided for Q4 2026, with no exact date given. Mirum's planned BLA is subject to this result.
• ~25 February 2027, est.: Q4 2026 results, estimated from the 25 February 2026 report a year earlier. They should test the $715–720M guide and show the first Atebrioz sales.
• ~31 March 2027, est.: Volixibat VANTAGE Phase 2b topline in primary biliary cholangitis, guided for Q1 2027.

What would change the view

An AZURE-4 result that misses its primary endpoint breaks the case, because the brelovitug filing depends on it. A cut to the $715–720M guide would break the commercial side, since the raise on 3 November 2026 is the newest support for the shares.

Quarterly spending that keeps rising without matching sales growth, or a share or convertible offering, would weaken the case without ending it. On price, a daily close below $75 would end it, since that sits well under the $82.39 close of 15 October 2026 that followed the approval and two positive Phase 3 results.

What it trades with

MarketBeat listed a beta of 0.75 on 5 November 2026, a measure showing the shares have moved less than the broad market. Company events are likely to outweigh index direction through the AZURE-4 result. That view is wrong if the shares show no distinct reaction to the readout.

Incyte (INCY) is linked through the Atebrioz license, but its payments from Mirum are limited to royalties and milestones: up to $48.0M regulatory, including the $25.0M already paid, and up to $15.0M commercial (10-Q).