Atebrioz / Zilurgisertib for Fibrodysplasia Ossificans Progressiva

As of October 2026, MARA’s assessment finds Atebrioz / Zilurgisertib’s reimbursement risk concentrated in clinical effectiveness and comparator selection, with care pathway integration a strength; the current MARA Rating and full rationale are available in the report.

The assessment also weighs patient population and subgroups: how closely the trial population matches the patients who would receive the drug in practice; payers often restrict funding to the groups where the evidence is strongest. The strength recorded in care pathway integration carries weight because that domain asks how the drug fits into the way care is organised today; a treatment that demands new infrastructure or displaces an established pathway faces extra scrutiny.

Rare Diseases

What payers will ask

Is the clinical benefit the kind payers reward? — Clinical effectiveness

The primary endpoint of the phase 2 study did not reach statistical significance, and while secondary endpoints showed numerical improvements, they were nominal. The study was small (N=63) and short-term (24 weeks), with no direct comparative data against active therapies like garetosmab or palovarotene.

Does the economic case hold at the expected price? — Cost effectiveness

No economic model, ICER, or cost-effectiveness analysis was presented for zilurgisertib.

Is there quality-of-life evidence payers weigh? — Quality of life

No HRQoL data or validated patient-reported outcomes were reported for zilurgisertib.

Does the safety profile hold up for payers? — Safety and Adverse Effects

Short-term safety data showed manageable tolerability with no deaths and low serious adverse event rates. However, the small sample size and short duration limit the assessment of rare or long-term adverse effects.

Was the drug compared against what payers expect? — Comparator Selection

The study used placebo as a comparator, which was relevant at the study’s initiation but is now insufficient given the availability of active treatments like garetosmab and palovarotene.

Is the population defined the way payers need it? — Patient Population and Subgroups

The trial population was limited to patients aged ≥12 years with recent disease activity and CAJIS <24, which limits representativeness for the broader FOP population.

Does the drug fit how care is delivered and paid for? — Care Pathway Integration

Oral administration fits well into existing care pathways, but specialized FOP-experienced clinicians are still necessary for comprehensive management.

Are the wider system costs understood? — Resource Use and Cost Implications

No budget-impact or resource-use information was presented for zilurgisertib.

Would the evidence survive payer scrutiny? — Evidence Quality and Robustness

The study was randomized and blinded, but the primary endpoint failed, and there was a lack of detailed statistical analysis plans and sensitivity analyses. [Expert decision MG: grade set to B++ — RCT completed ]

How exposed is the case to uncertainty? — Uncertainty, Sensitivity, and Broader Impacts

High uncertainty due to the failed primary endpoint, reliance on secondary measures, and lack of active comparator data. Structural uncertainties remain unresolved.

Request the current rating

Be alerted when this rating changes:

Related Reimbursement Risk Assessments

Full Legal Disclaimer and Usage Terms

The MARA Rating® is an independent opinion of a drug’s market access pharma risk profile and is provided for informational purposes only—not as investment, medical, legal or any other type of advice. See our full disclaimer here.