Today, May 6, 2026, Mirum Pharmaceuticals announced to its investors that it has licensed the drug zilurgisertib, an ALK2 kinase inhibitor, currently being developed by Incyte for FOP (PROGRESS Phase 2 trial, NCT 05090891).
And in even more exciting news, we now know that data from Part 1 of the PROGRESS trial (patients aged 12 and up) has been filed with the US Food and Drug Administration (FDA) through a New Drug Application (NDA). The NDA has been accepted and has Priority Review, with an expected Prescription Drug User Fee Act (PDUFA) (i.e., decision) date of September 26, 2026.
As of this announcement, the PROGRESS trial data have not yet been published or presented at a major medical conference, so there is no publicly available data on safety or effectiveness in individuals with FOP aged 12 and up. We hope that this data will become available this summer and will also be presented at the FOP Drug Development Forum in late August 2026.
Press Release from Mirum Pharmaceuticals
Frequently Asked Questions (FAQs) - NEW
About Zilurgisertib
FOP patients harbor mutations in the ALK2 protein (also known as ACVR1) that drive excessive bone morphogenetic protein (BMP) signaling, which regulates cartilage and bone development.
Zilurgisertib (INCB000928) is an oral investigational drug designed to target and block this disease-causing mutant FOP protein hyperactivity. In preclinical studies, zilurgisertib demonstrated potency for the target kinase, selectivity, safety and strong suppression of heterotopic ossification (HO) in animal models.
Important Reminders
This announcement does not mean that the drug being tested in this trial, zilurgisertib, has been approved and is available for doctors to prescribe.
However, individuals with FOP, ages 12 and over, living in the United States, may be able to use zilurgisertib through a new Compassionate Use Program opened by Mirum and Incyte.
A licensed doctor may request access to zilurgisertib for a patient through the Compassionate Use Program at https://mirumpharma.com/our-science/pipeline in the "Expanded Access/Compassionate Use" section at the bottom of the page. Mirum reserves the right to revise this policy at any time.
The PROGRESS clinical trial is still active globally with two cohorts but is not currently recruiting, so no new participants can join the trial at this time.
Cohort 1: Ages 12+
Cohort 2: Ages 6 to <12
More Information
Below you'll find highlights from Mirum's press release and a letter to the FOP community from Chris Peetz, Mirum's Chief Executive Officer (CEO).
Press Release Highlights
Mirum Pharmaceuticals Reports First Quarter 2026 Financial Results and Provides Business Update
May 6, 2026
- Q1 2026 net product sales of $159.9 million
- 2026 net product sales guidance increased to $660 to $680 million
- Volixibat VISTAS Phase 2b study met primary endpoint
- Brelovitug Phase 2b portion of AZURE-1 study met primary endpoint
- In-licensed exclusive worldwide rights to zilurgisertib (ALK2 inhibitor) for FOP; FDA Priority Review granted with September 26, 2026 PDUFA date
- Conference call to provide business updates today, May 6 at 1:30 p.m. PT / 4:30 p.m. ET
FOSTER CITY, Calif.--(BUSINESS WIRE)-- Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM), a leading rare disease company, today reported financial results for the first quarter 2026 and provided a business update.
“2026 is off to an excellent start, driven by strong commercial momentum, the recent VISTAS and AZURE-1 topline results, disciplined clinical execution, and continued expansion of our pipeline,” said Chris Peetz, Chief Executive Officer of Mirum. “We also announced today the in-license of zilurgisertib, a once-daily oral ALK2 inhibitor for fibrodysplasia ossificans progressiva from Incyte. Zilurgisertib has completed a pivotal study for FOP and its NDA has been accepted, creating the potential for an additional product launch for our rare genetic disease team later this year. We’re grateful to Incyte for all the work they have conducted on this program and look forward to potentially bringing another high impact medicine to patients.”
Business Development: Obtained Exclusive Worldwide Rights to Zilurgisertib
- Entered into an exclusive license agreement with Incyte for worldwide rights to zilurgisertib, an ALK2 inhibitor in development for fibrodysplasia ossificans progressiva (FOP).
- U.S. FDA accepted the New Drug Application (NDA) for zilurgisertib in FOP patients 12 years and older and granted Priority Review with a Prescription Drug User Fee Act (PDUFA) date of September 26, 2026.
- Results from the pivotal Phase 2 PROGRESS study in FOP formed the basis of the NDA filing for zilurgisertib; Incyte plans to present the results at an upcoming medical conference.
- In return for the exclusive license of worldwide rights to zilurgisertib, Incyte received an upfront payment of $16 million and is eligible to receive additional development and regulatory milestone payments, as well as sales-based milestones and tiered royalties on worldwide net sales in the mid-to-high single digit percent range.
About Zilurgisertib
Zilurgisertib is an investigational, oral, small molecule, activin receptor-like kinase 2 (ALK2) inhibitor in development for the treatment of Fibrodysplasia Ossificans Progressiva (FOP). Zilurgisertib is designed to inhibit the ALK2 receptor which is abnormally active in most patients with FOP and leads to bone formation in soft tissues, a process known as heterotopic ossification (HO). FOP is an ultra-rare genetic disease that affects approximately 300 patients in the U.S. and 900 worldwide, with diagnosis typically occurring in early childhood. Zilurgisertib was evaluated in the PROGRESS pivotal Phase 2 study, which formed the basis of a new drug application (NDA). The FDA has accepted the NDA for zilurgisertib in FOP under Priority Review with a Prescription Drug User Fee Act (PDUFA) date of September 26, 2026.
Mirum licensed zilurgisertib from Incyte for development and commercialization globally.
About Mirum Pharmaceuticals
Mirum Pharmaceuticals (NASDAQ: MIRM) is a leading rare disease company with a global footprint of approved products and a broad pipeline of investigational medicines. Purpose-built to bring forward breakthrough medicines for people with overlooked conditions, Mirum focuses on rare liver and rare genetic diseases, where it has built deep expertise and strong connections to patient communities. The company’s commercial portfolio includes LIVMARLI® (maralixibat) for Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis (PFIC), CHOLBAM® (cholic acid) for bile-acid synthesis disorders, and CTEXLI® (chenodiol) for cerebrotendinous xanthomatosis (CTX).
Mirum’s clinical-stage pipeline includes volixibat, an IBAT inhibitor in late-stage development for primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC), brelovitug, a fully human monoclonal antibody in late-stage development for chronic hepatitis delta virus (HDV), zilurgisertib, an ALK2 inhibitor under regulatory review with the FDA for fibrodysplasia ossificans progressiva (FOP), and MRM-3379, a PDE4D inhibitor being evaluated for Fragile X syndrome (FXS).
Mirum’s success is driven by a team dedicated to advancing high impact medicines through strategic development, disciplined execution and purposeful collaboration across the rare disease ecosystem. Learn more at www.mirumpharma.com and follow Mirum on Facebook, LinkedIn, Instagram and X.
Letter from Mirum's CEO, Chris Peetz
Dear FOP Community,
Chief Executive Officer, Mirum Pharmaceuticals
I am truly excited to introduce Mirum Pharmaceuticals, Inc. (Mirum) as an additional partner to Incyte in the continued development of the investigational therapy, zilurgisertib. Along with the FOP community, we share a goal of bringing new treatment options to people living with FOP as quickly as possible.
For those of you who are unfamiliar with Mirum, we are a multi-product, commercial-stage rare disease company with years of experience supporting people living with rare and ultra-rare diseases. We are relentlessly focused on conditions where the burden is profound and the unmet need remains high. Mirum recently entered into an agreement with Incyte for the worldwide commercialization rights to zilurgisertib. Incyte will continue to lead development of zilurgisertib, including the ongoing PROGRESS study, and there are no planned changes to the conduct of the study.
We would like to recognize the incredible dedication and work to date of individuals living with FOP, their families, researchers, clinicians, advocates, and industry. Together, these efforts have helped advance progress toward improving the lives of those affected by this devastating condition.
As part of our shared commitment to advancing treatment options and supporting patients, a New Drug Application for zilurgisertib has been accepted by the FDA and granted Priority Review with an action date of September 26, 2026, and Incyte and Mirum are also pleased to offer access for new patients 12 years of age or older in the United States through a Compassionate Use program. For more information, please contact your physician.
We are honored to be part of the global FOP community and look forward to working together with urgency and purpose to make a meaningful difference for people living with FOP and their families.
Sincerely,
Chris Peetz
Chief Executive Officer
Mirum Pharmaceuticals, Inc.
Frequently Asked Questions (FAQs) - NEW
Read the Frequently Asked Questions here.
If you have a question about these announcements or any of the other FOP clinical trials, email [email protected].
Welcome and Thank You
We are pleased to welcome Mirum to the FOP community and thank the team at Incyte for their incredible commitment that brought zilurgisertib through a Phase 2 trial and a New Drug Application that has been accepted for Priority Review by the FDA.
Thank you to the FOP community members from around the world who have actively participated in the PROGRESS trial.
