Your first 90 days
Your first 90 days on Pasatru for FOP
What happens before the first fill, the days that matter, the label's rules and who to call, from the label, the drugmaker's own program and one insurer's written rules.
Pasatru is not a pill, and it is not a shot you give yourself. A trained healthcare provider gives it into a vein once every 4 weeks, at an infusion center or at home. Before the first infusion, anyone who can become pregnant is asked to take a pregnancy test, because Pasatru can harm an unborn baby. This page lays out the first 3 months from the FDA label, Regeneron's support program and one insurer's published policy.
What has to happen before the first bottle ships
Pasatru has no REMS, so the first infusion waits on a pregnancy test where it applies, an insurance approval and an infusion site. These are the 8 things in the way, in order.
An FOP diagnosis, in an adult
The label covers adults with FOP and says safety and effectiveness in children have not been established.
- In the trial behind the approval, every patient had FOP confirmed by a change in the ACVR1 gene known to cause it.FDA label
A pregnancy test, for anyone who can become pregnant
The label says Pasatru must not be used during pregnancy, because it can harm an unborn baby.
- It asks the prescriber to verify that a patient who can become pregnant is not pregnant before starting.
- The Medication Guide says the healthcare provider will ask for a pregnancy test.FDA label
A birth control plan
The label calls for effective birth control during treatment and for 6 months after the last dose.
- The Medication Guide suggests talking with the healthcare provider about which birth control methods may be right.FDA label
A full list of medicines
The Medication Guide asks patients to tell the healthcare provider about all their medicines, including over-the-counter medicines, vitamins and herbal supplements.
- It also asks patients to mention breastfeeding and any concern about male fertility.FDA label
A current weight
The dose is worked out from body weight, starting at 10mg for each kilogram.
- Each vial holds 300mg, so a dose of 600mg for a 60kg (about 132 pounds) adult uses 2 vials.FDA label
A place for the infusion
Regeneron's patient brochure says Pasatru can be given at an infusion center, which may be a standalone clinic or at a hospital, or at home.
- A trained healthcare provider gives every infusion, and your healthcare provider helps decide which site is best.
- The brochure adds that insurance coverage varies and that not all hospitals or infusion centers offer Pasatru.Regeneron patient brochure
Enrolling in myRARE
myRARE is Regeneron's patient support program for people prescribed Pasatru.
- Its Pasatru page says it helps patients navigate insurance coverage, handle logistical challenges with treatment and connect to financial support options.
- Enrollment starts on that page, and the phone line is 1-877-372-7287, option 1.myRARE for Pasatru
The insurance approval
Blue Cross Blue Shield of Michigan, as one example, requires prior authorization for Pasatru.
- Its policy asks for chart notes and for genetic testing that shows a change in the ACVR1 gene.BCBS Michigan policy
The days that matter
Counted from the first infusion on day 1, with one infusion every 4 weeks after that and no blood test scheduled by the label. Type your first-dose date and the tiles become real dates you can add to your calendar.
The tiles below count days from a first dose. Enter the date of yours, or the date you expect, and each tile becomes a real date on your calendar.
The date stays on your device. It is not sent to Trial Friend or anyone else. The calendar file works with Apple, Google and Outlook calendars.myRARE enrollment and the insurance check
After enrolling in myRARE, you are partnered with a Patient Navigator, according to Regeneron's brochure.
- The navigator helps explain your health insurance benefits and gives updates throughout the insurance approval process.
Choosing where the infusions happen
Regeneron's brochure lists an infusion center, which may be a standalone clinic or at a hospital, or home.
- It says your healthcare provider will help determine which site of care is best for you.
Pregnancy test, where it applies
The label asks the prescriber to verify that a patient who can become pregnant is not pregnant before starting Pasatru.
- It also calls for effective birth control during treatment and for 6 months after the last dose.
First infusion, 60 minutes
The recommended starting dose is 10mg/kg, given into a vein over 60 minutes.
- The label says an infusion pump should be used to control how fast the medicine goes in.
Two weeks in, skin and nose
Abscesses, acne, increased hair growth and nosebleeds were among the most common side effects in the trial.
- The Medication Guide says to call the healthcare provider right away about signs of a skin infection or a nosebleed lasting more than 20 minutes.
An infusion every 4 weeks
The Medication Guide says Pasatru should be given 1 time every 4 weeks.
- If an appointment is missed, it says to call the healthcare provider as soon as possible to reschedule.
- The next infusions are then scheduled every 4 weeks from the date of that dose.
An infusion every 4 weeks, number 2
An infusion every 4 weeks, number 3
The label, revision by revision
The FDA lists which sections changed in each revision of a label. These are the revisions the current Pasatru label records, dated by the FDA, with a plain note on what each one meant for a patient. Older references and handouts can lag these by months.
How the label says to take it
The parts of the prescribing information and the patient leaflet that come up in the first 3 months, in plain words.
- Given by a healthcare provider, every 4 weeks
The Medication Guide says a healthcare provider gives Pasatru through a needle placed into a vein, over 60 minutes.
- It says Pasatru should be given 1 time every 4 weeks.FDA label
- The dose follows weight
The recommended starting dose is 10mg/kg, given over 60 minutes once every 4 weeks.
- The label lets the prescriber lower it to 3mg/kg once every 4 weeks if 10mg/kg is not tolerated.FDA label
- If an infusion is missed
The Medication Guide says to call the healthcare provider as soon as possible to reschedule a missed infusion appointment.
- After the missed dose is given, the next infusion is scheduled every 4 weeks from the date of that dose.FDA label
- Pregnancy and birth control
The label says Pasatru must not be used during pregnancy.
- It calls for effective birth control during treatment and for 6 months after the last dose, for anyone who can become pregnant.
- For a pregnancy or a possible pregnancy during treatment, the Medication Guide says to stop taking Pasatru immediately and call the healthcare provider right away.FDA label
- Pregnancy tests later on
Regeneron's myRARE page says the healthcare provider may ask for pregnancy tests periodically, as needed, throughout treatment and for at least 6 months after stopping.
- The FDA Medication Guide itself mentions only the pregnancy test before starting treatment.myRARE for Pasatru
- Breastfeeding
The label says breastfeeding is not recommended during treatment and for 6 months after the last dose.
- It is not known whether Pasatru passes into breast milk.
- The Medication Guide suggests asking the healthcare provider about the best way to feed the baby.FDA label
- Male fertility
Pasatru may affect the ability to father a child, according to the Medication Guide, and the label bases that on animal studies.
- The Medication Guide says to talk with the healthcare provider if this is a concern.FDA label
- Every medicine on the list
The label says no drug interaction studies have been done with Pasatru.
- The Medication Guide asks patients to tell the healthcare provider about all their medicines, including over-the-counter medicines, vitamins and herbal supplements.FDA label
- What happens at the infusion
Regeneron's brochure says a healthcare provider may check your vital signs and ask how you are feeling.
- A needle is placed in the arm and connected to an infusion pump, and the infusion takes 60 minutes.
- The brochure says to tell the healthcare provider right away about any side effects or reactions to the infusion.Regeneron patient brochure
- How the vials are stored
The label says unopened vials are stored in a refrigerator at 36 to 46 degrees Fahrenheit, in the original carton to protect them from light.
- It also says the vials must not be frozen or shaken.FDA label
What the label says to act on
The symptoms the label singles out, and what it tells patients and prescribers to do about each. If any of these happen, the label's instruction is the one to follow, with your care team.
Signs of a skin infection
The Medication Guide lists redness, skin that feels warm to the touch, swelling, pain or tenderness, fever and feeling generally unwell.
- It says skin infections such as abscesses and cellulitis can need treatment or a hospital stay.
- It says to call the healthcare provider right away if any of these signs appear.FDA label
A nosebleed that is heavy or will not stop
The Medication Guide says to tell the healthcare provider right away about a nosebleed that is severe or heavy, or lasts more than 20 minutes.
- The same applies to one that does not stop with basic first aid, such as pinching the nose with continuous firm pressure.
- In the FOP trials, 1 serious nosebleed needed a hospital stay, according to the label.FDA label
A possible pregnancy
The Medication Guide warns that Pasatru can harm an unborn baby, including serious birth defects, if taken during pregnancy.
- For a pregnancy or a possible pregnancy during treatment, it says to stop taking Pasatru immediately and call the healthcare provider right away.FDA label
Common side effects in the trial
On the 10mg/kg dose, abscesses affected 35% of patients against 10% on placebo, and acne 30% against 10%.
- Increased hair growth affected 26% against none on placebo, and mouth sores 26% against 5%.
- Loss of eyebrow or eyelash hair affected 26% against 19%, and nosebleeds 17% against 24%.
- On the 3mg/kg dose, nosebleeds affected 53% of patients and increased hair growth 42%.
- Rash affected 26% on that dose against none on placebo, and infected hair follicles 16% against 10%.
- Nail infections affected 11% against none on placebo.FDA label
Why the pharmacy or the insurer says no, and what fixes it
Most first-fill delays are one of these. Knowing which one tells you who to call.
- The patient is under 18The label covers adults with FOP and says safety and effectiveness in children have not been established. The FOP specialist can explain what that means for a younger patient.FDA label
- A pregnancy has not been ruled outThe label asks the prescriber to verify that a patient who can become pregnant is not pregnant before starting Pasatru. The Medication Guide says the healthcare provider will ask for a pregnancy test.FDA label
- No genetic test result with the requestBlue Cross Blue Shield of Michigan's policy asks for FOP confirmed by genetic testing that shows an ACVR1 mutation. The specialist's office sends that report, along with chart notes, when it asks the plan for approval.BCBS Michigan policy
- Another FOP medicine is on fileBlue Cross Blue Shield of Michigan's policy says Pasatru is not to be used with other targeted FOP therapies, such as Sohonos (palovarotene). The specialist's office can tell the plan which FOP medicines are being taken now.BCBS Michigan policy
- The plan wants its preferred drugs firstBlue Cross Blue Shield of Michigan's policy asks for trial and failure of, a contraindication to, or intolerance of its preferred drugs. The policy document does not name those drugs, so the specialist's office checks the plan's medical drug list.BCBS Michigan policy
- The plan has not set its rules yetBlue Shield of California's commercial policy, effective November 1, 2026, says its coverage criteria are pending committee approval. Until then it reviews every request for medical necessity and asks for chart notes, lab results or other clinical information.Blue Shield of California policy
- No infusion site is set up yetRegeneron's brochure says insurance coverage varies and that not all hospitals or infusion centers offer Pasatru. It suggests talking to your care team about which options are available to you.Regeneron patient brochure
- A cost you cannot payRegeneron's brochure says a Patient Navigator can tell you if you qualify for myRARE support programs or point to other financial assistance resources. The Pasatru pages we read did not publish copay amounts, income limits or rules for Medicare and Medicaid.Regeneron patient brochure
Blue Cross Blue Shield of Michigan prior authorization policy, October 8, 2026
- The FDA-approved indication and the FDA-approved age, which the label sets as adults with FOP
- FOP confirmed by genetic testing that shows an ACVR1 mutation
- Not used in combination with other targeted therapies for FOP, such as Sohonos (palovarotene)
- Trial and failure of, a contraindication to, or intolerance of the preferred drugs on the plan's utilization management medical drug list
- Chart notes and patient-specific documentation sent with the request
Approval length. One year at a time, with quantity limits that follow FDA-recommended dosing. Renewal needs clinical documentation that the criteria are still met and that the medicine is providing clinical benefit.
This is one plan's medical drug policy, and other plans differ. It was written after the August 2026 label, which it cites. The policy says coverage and approval length may differ for Medicare Part B members. It does not name the preferred drugs in its fourth criterion. BCBS Michigan policy
Who to call, and what they can do
The drugmaker's program handles most of the first-fill problems above. Charity funds and foundation help are on the help paying page.
- The Pasatru line is also written 1-877-3PASATRU, and option 1 reaches myRARE
- Help navigating your insurance coverage
- Help with logistical challenges related to your treatment
- Connection to financial support options
- Help understanding your infusion coverage
- A Patient Navigator who helps explain your health insurance benefits and gives updates throughout the insurance approval process Regeneron patient brochure
- Treatment confirmations and updates by text message, and check-ins from the Patient Navigator about your treatment Regeneron patient brochure
- The Patient Navigator can let you know if you qualify for myRARE support programs or identify other financial assistance resources Regeneron patient brochure
- Regeneron's approval announcement also gives a general myRARE line, 1-833-469-7273 (1-833-4my-RARE) Regeneron press release
Details as the drugmaker publishes them. myRARE for Pasatru
Five questions for the pharmacist or the support line
- Where can the infusions happen under my insurance, and is home infusion an option for me?
- Who schedules the infusion every 4 weeks, and who do we call if an appointment has to move?
- Which weight is the dose based on, and how many vials does that dose use?
- If a nosebleed or signs of a skin infection start at night or on a weekend, who do we call?
- Will pregnancy tests be repeated during treatment, and how often?
- Does myRARE have a support program that fits my type of insurance?
Questions people ask in the first weeks
Is Pasatru approved for children with FOP?
No, the FDA approved Pasatru only for adults with FOP. The label says safety and effectiveness in children have not been established. ClinicalTrials.gov lists a Regeneron trial in children and teenagers under 18, called OPTIMA-2, as not yet recruiting. The record sets the youngest age at 4 for participants in the United States and 2 elsewhere. That record, updated October 20, 2026, gives a planned start in February 2027.
How often is Pasatru given?
Pasatru is given once every 4 weeks, as an infusion into a vein over 60 minutes. The recommended starting dose is 10mg/kg, and the label allows 3mg/kg if that dose is not tolerated.
Why does Pasatru need a pregnancy test?
The label says Pasatru can harm an unborn baby and must not be used during pregnancy. It asks the prescriber to verify that anyone who can become pregnant is not pregnant before starting. The label also calls for effective birth control during treatment and for 6 months after the last dose.
What if a Pasatru infusion is missed?
The Medication Guide says to call the healthcare provider as soon as possible to reschedule. After the missed dose is given, the next infusion is scheduled every 4 weeks from the date of that dose.
Can Pasatru be given at home?
Regeneron's patient brochure says Pasatru can be given at an infusion center or at home, by a trained healthcare provider. It says your healthcare provider helps determine which site of care is best for you. The brochure adds that insurance coverage varies and that Regeneron does not recommend any particular site of care.
Does Pasatru remove bone that has already formed?
The label makes no claim about bone that has already formed. Pasatru is approved to reduce the formation of new bone lesions outside the skeleton and flare-ups assessed by a clinician.
How well did Pasatru work in its trial?
The trial behind the approval enrolled 63 adults with FOP and counted new bone lesions on whole-body CT scans at week 56. Patients on placebo had 19 new bone lesions in total, against 2 on the 10mg/kg dose and 1 on the 3mg/kg dose. Clinicians counted 9 flare-ups on 10mg/kg, 53 on 3mg/kg and 66 on placebo. Regeneron's brochure says the flare-up result on 3mg/kg was not clear enough to rule out chance. Flare-ups reported by patients did not differ significantly between the groups, according to the label.
Does Pasatru have a boxed warning or a REMS?
Pasatru has neither a boxed warning nor a REMS under its August 2026 label. The label's warnings cover harm to an unborn baby, skin and soft tissue infections, and nosebleeds. Pregnancy is the one condition in which the label says Pasatru must not be used.
Does Pasatru need blood tests?
The label does not schedule any blood test for Pasatru. Its one required check is verifying that anyone who can become pregnant is not pregnant before starting. The label names no other routine test or scan.
Free email alert
Hear when the Pasatru label changes
One email the day the FDA revises the Pasatru label, with what changed in plain words. No trial alerts, no newsletter.
Label changes for Pasatru only, usually a few a year and some years none. Stop anytime. We never share your email. Privacy policy
Want the whole condition instead? Follow Fibrodysplasia ossificans progressiva (FOP) for new trials, FDA decisions and label changes for every treatment.
Sources
- PASATRU (garetosmab-grts) injection, for intravenous use, prescribing information and Medication Guide, Revised 8/2026, Regeneron Pharmaceuticals, via DailyMed, August 14, 2026.
- BLA 761508 approval letter, Pasatru (garetosmab-grts), FDA, August 19, 2026.
- FDA Approves Second Treatment for Fibrodysplasia Ossificans Progressiva, FDA, August 19, 2026.
- Pasatru™ (garetosmab-grts) First and Only FDA-approved Treatment Demonstrating Reduction in New Heterotopic Ossification (HO) Lesions and Clinician-Assessed Flare-ups in a Placebo-controlled Trial in Adults with Fibrodysplasia Ossificans Progressiva (FOP), Regeneron Pharmaceuticals, August 19, 2026.
- Pasatru, myRARE patient support program page, Regeneron Pharmaceuticals, November 11, 2026.
- PASATRU consumer brochure, US.GAR.26.05.0001, September 2026 version, Regeneron Pharmaceuticals, November 11, 2026.
- Pasatru (garetosmab-grts) medical benefit drug policy, P&T date 10/08/2026, Blue Cross Blue Shield of Michigan and Blue Care Network, October 8, 2026.
- garetosmab-grts (Pasatru) Commercial Medical Benefit Drug Policy, effective 11/01/2026, Blue Shield of California, November 1, 2026.
- A Study to Assess Safety, Tolerability and Efficacy of Garetosmab Versus Placebo Administered Intravenously (IV) in Adult Participants With Fibrodysplasia Ossificans Progressiva (FOP), NCT05394116, ClinicalTrials.gov, record updated July 17, 2026, July 17, 2026.
- A Study to Investigate the Safety, Pharmacokinetics (PK), and Efficacy of Garetosmab in Children and Adolescents With Fibrodysplasia Ossificans Progressiva (FOP), NCT07559513, ClinicalTrials.gov, record updated October 20, 2026, October 20, 2026.
- Efficacy and safety of garetosmab, an activin A-blocking antibody, in fibrodysplasia ossificans progressiva (OPTIMA): a randomised, double-blind, placebo-controlled, phase 3 trial, The Lancet, via PubMed, September 28, 2026.
This page explains what the FDA label, the drugmaker's support program and an insurer policy say. It is not medical advice and does not tell anyone to start, stop or change a medicine. Dosing, test timing and restarts after a gap are decisions for the prescribing FOP specialist. Found an error? Use the report link in the footer and it will be checked against the source.