Besremi (ropeginterferon alfa-2b-njft)
An approved treatment for Polycythemia Vera and Essential Thrombocythemia.
The same compound appears under different names depending on the context. Here is how to identify Ropeginterferon alfa-2b-njft wherever you encounter it, plus the key facts at a glance.
- Generic name
- Ropeginterferon alfa-2b-njft
- Brand name
- Besremi
- Development code
- P1101
- Drug class
- Interferon alfa-2b (pegylated)
- Manufacturer
- PharmaEssentia (PharmaEssentia Corporation, Taipei, Taiwan, through PharmaEssentia USA)
- How it's taken
- Besremi is injected under the skin of the lower belly, at least 2 inches from the belly button, or the top of the thigh.
An injection under the skin, usually given every 2 weeks, approved by the FDA on November 12, 2021 for adults with polycythemia vera and on August 28, 2026 for adults with essential thrombocythemia. In the SURPASS ET trial against anagrelide, 37.4% of patients on Besremi had a durable response at both month 9 and month 12, against 3.6% on anagrelide. It carries a boxed warning for serious neuropsychiatric, autoimmune, ischemic and infectious disorders.
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Where Ropeginterferon alfa-2b-njft fits
An interferon, a different kind of drug from the JAK inhibitor ruxolitinib (Jakafi), which is approved for adults with polycythemia vera whose disease did not respond well enough to hydroxyurea or who cannot tolerate it, and from the hepcidin mimetic rusfertide (Mimrylo). Its polycythemia vera approval is for adults without a prior-treatment requirement, and its main PV trial included newly diagnosed patients and people switching from hydroxyurea. In essential thrombocythemia it was compared head to head with anagrelide in SURPASS ET.
How Ropeginterferon alfa-2b-njft works
Interferon alfa is a protein the immune system makes naturally. Besremi is a lab-made version, interferon alfa-2b, with a chain of polyethylene glycol (PEG) attached to it[1]. It binds a receptor on bone marrow cells called the interferon alfa receptor (IFNAR), which switches on signaling enzymes called JAK1 and TYK2 and proteins called STATs that change which genes the cell turns on. The label says the exact way this calms the overactive marrow in polycythemia vera and essential thrombocythemia is not fully understood[1]. The goal of treatment is steady blood counts: hematocrit (the share of the blood made up of red cells) below 45%, platelets below 400 x 10^9/L and white blood cells below 10 x 10^9/L. In people with polycythemia vera, its half-life is about 7 days, and it is given every 2 weeks[1].
Mechanism: Pegylated interferon alfa-2b that binds the interferon alfa receptor (IFNAR) on bone marrow cells and switches on JAK1, TYK2 and STAT signaling; the label says the exact way it controls polycythemia vera and essential thrombocythemia is not fully understood
Side effects and safety
- Depression and suicide. Psychiatric reactions in 10% of patients with ET and serious ones in 3% with PV. Not for people with a history of severe depression, suicidal thoughts or a suicide attempt.
- Thyroid and other hormone problems. Overactive or underactive thyroid and thyroid inflammation occurred, and interferon alfa-2b products have caused high blood sugar, including new type 1 diabetes. Thyroid function is checked if symptoms appear.
- Heart problems and blood clots. Interferon alfa can cause heart muscle disease, heart attack and abnormal heart rhythm, and 3 clotting events occurred on Besremi in SURPASS ET. Avoid with severe or unstable heart disease or a recent stroke or heart attack.
- Low blood counts. Low platelets, red cells and white cells can raise the risk of bleeding and infection. Infection occurred in 45% of ET patients (4% serious) and 48% of PV patients (8% serious).
- Liver injury. ALT rose to at least 3 times normal in 20% of ET patients. Not for people with moderate or severe liver impairment (Child-Pugh B or C).
- Eye problems. Eye disorders in 23% of patients in both diseases, including blurred vision, cataract and dry eye. Eye exams before and during treatment, especially with diabetes or high blood pressure.
- High triglycerides and pancreatitis. High triglycerides in 9% of ET patients and pancreatitis in 2.2% of PV patients. Triglycerides are checked before and during treatment.
- Lung, colon, kidney, skin and dental problems. Stop for lung infiltrates, signs of colitis or severe kidney impairment. Good oral hygiene and regular dental checkups are advised.
- Harm to an unborn baby. Pregnancy test before starting, and effective birth control during treatment and for at least 8 weeks after the last dose. No breastfeeding during treatment and for 8 weeks after.
- Complete blood count every 2 weeks while the dose is being raised, then every 3 to 6 months
- Liver enzymes and liver function before starting and during treatment
- Triglycerides before starting and from time to time during treatment
- Kidney function (serum creatinine) before starting and during treatment
- Eye exams before and during treatment
- Pregnancy test before starting in women who could become pregnant
- Watch for depression or other mood changes
Besremi has a boxed warning. Interferon alfa products can cause or worsen fatal or life-threatening neuropsychiatric, autoimmune, ischemic (reduced blood flow) and infectious disorders, and treatment is stopped if these stay severe or keep getting worse. In many but not all cases they go away after stopping[1]. In the SURPASS ET trial in essential thrombocythemia, the most common side effects on Besremi vs anagrelide were raised liver enzymes (54% vs 14%), anemia (28% vs 30%), fever (26% vs 9%), a rise in a urine protein called beta-2 microglobulin (25% vs 4%), bacterial infection (24% vs 23%), itching (22% vs 19%) and weight loss (21% vs 6%). Bleeding was reported in 17% on Besremi and 38% on anagrelide, and headache in 15% vs 31%[1]. In the PEGINVERA trial in polycythemia vera, which had no comparison group and followed patients for up to 7.5 years, the most common were flu-like illness (59%), joint pain (47%), fatigue (47%), itching (45%), sore throat or common cold symptoms (43%), muscle and bone pain (41%) and headache (39%). Depression was reported in 20% and was the most common reason for stopping, in 8%[1]. Other warnings cover thyroid problems and high blood sugar, heart problems, low blood counts, allergic reactions, pancreatitis, colitis, lung problems, eye problems, high triglycerides, liver injury, kidney problems, tooth and gum problems, skin reactions, dizziness or sleepiness that can affect driving, and harm to an unborn baby[1].
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Ropeginterferon alfa-2b-njft
Besremi is injected under the skin of the lower belly, at least 2 inches from the belly button, or the top of the thigh. A healthcare professional, the patient or a caregiver can give it after training. It comes as a 500 mcg prefilled syringe or a 500 mcg prefilled pen, and both are set in 50 mcg steps[1]. For essential thrombocythemia, the first dose is 250 mcg, then 350 mcg at week 2, then 500 mcg every 2 weeks from week 4 on. If side effects occur, the dose is lowered in steps down to 100 mcg[1]. For polycythemia vera, the starting dose is 100 mcg every 2 weeks, raised by 50 mcg every 2 weeks up to 500 mcg until blood counts are steady. People switching from hydroxyurea start at 50 mcg alongside hydroxyurea, taper hydroxyurea during weeks 3 to 12 and stop it by week 13. After at least 1 year of steady counts on a stable dose, the PV schedule can stretch to every 4 weeks[1]. Phlebotomy may still be needed while the PV dose is being raised. Besremi is stored in the refrigerator at 36 to 46 degrees F, never frozen, and left in its carton at room temperature for 15 to 30 minutes before injecting[1].
Availability and cost
Only available as the brand-name product.
Help paying for Besremi
Pick your insurance to see which help fits. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE; charity funds are the usual route there.
- Copay help
Copay and Coinsurance Assistance Program: eligible patients with commercial insurance that covers Besremi may pay as little as $0 per month toward copay, coinsurance or deductible costs. Must live in the US or a US territory with a valid prescription from a US physician. Not for Medicare, Medicaid, TRICARE, Veterans Health Administration or other federal or state plans, for cash-paying patients, or where the plan reimburses the full cost of Besremi.
For: private insurance · source - Free medicine program
Patient Assistance Program: PharmaEssentia may provide Besremi at no cost to eligible people who are uninsured or whose prescription coverage does not include Besremi. Must live in the US or a US territory, have a valid US prescription and meet financial criteria, which the program page does not list.
For: no insurance, underinsured · source - Bridge or quick-start supply
Temporary Supply Program: patients facing insurance delays or gaps in coverage may be eligible for a temporary supply of Besremi.
The official page does not say who qualifies. Ask the program. · source - Other support
A PharmaEssentia SOURCE nurse can help with dosing and the injection process, and the program helps patients find outside organizations that may help with other treatment-related needs.
The official page does not say who qualifies. Ask the program. · source
Good to know: The program covers Besremi for both polycythemia vera and essential thrombocythemia. Case managers are available Monday to Friday, 8 AM to 8 PM ET; the prescriber faxes the enrollment form to 800-700-5065. No annual copay maximum or fill limit is stated on the page, which sends patients to BESREMiCopay.com to enroll. The temporary supply program appears on the provider page, and its length is not stated.
- From a charity · Blood Cancer United (formerly The Leukemia & Lymphoma Society)Clinical Trials Co-Pay Fund (all blood cancers) fundOpen
Pays for: Insurance premiums and treatment-related copays, deductibles and coinsurance, up to $3,500 per year. Requires health insurance (any kind).
- From a charity · Blood Cancer United (formerly The Leukemia & Lymphoma Society)Patient Aid Program fundOpen
Pays for: One-time $100 stipend for non-medical expenses (transportation, food, housing, utilities); no income or insurance requirement, up to $100 per year.
The foundation says: “CURRENT FUND STATUS: Open. Fund is currently Open.” - From a charity · CancerCare Co-Payment Assistance FoundationMyeloproliferative Neoplasms fundOpen
Pays for: Copays, coinsurance and deductibles for treatment, up to $7,000 per year. Requires Medicare, Medicaid or TRICARE.
The foundation says: “Status: Open. Grant Amount: $7,000 (Initial Grant Amount $7,000; Program CAP Amount $10,000)” - From a charity · TotalAssist (formerly PAN Foundation)Myeloproliferative Neoplasms fundOpen
Pays for: Out-of-pocket costs for approved medications, up to $9,500 per year. Requires health insurance (any kind).
- From a charity · The Assistance FundMyeloproliferative Neoplasms (MPN) fundWaitlist
Pays for: Copays, coinsurance, deductibles and other health-related expenses.
The foundation says: “WAITLIST — Accepting Waitlist Patients. TAF is currently accepting requests to join the enrollment waitlist for this program. Waitlists a…”
Clinical trial results
SURPASS ET (NCT04285086) randomized 174 adults with essential thrombocythemia whose disease had not responded well enough to hydroxyurea, or who could not tolerate it, to Besremi (91) or anagrelide pills (83) for 12 months; 96% of patients were Asian, 82% had a JAK2 V617F mutation and 12% a CALR mutation. A durable response at both month 9 and month 12, meaning platelets at or below 400 x 10^9/L, white cells below 9.5 x 10^9/L, no spleen growth and no bleeding or clotting events, occurred in 37.4% on Besremi vs 3.6% on anagrelide. Among patients who completed the study, 1 of 82 on Besremi and 10 of 51 on anagrelide had a blood clot event over 12 months[1][9]. Its safety data were pooled with a single-arm study, EXCEED ET (NCT05482971)[1][10]. For polycythemia vera, the label's efficacy results come from PEGINVERA (NCT01193699), a single-arm trial sponsored by AOP Orphan Pharmaceuticals, in 51 adults, all with a JAK2 V617F mutation, of whom 16% were newly diagnosed and 33% were taking hydroxyurea at entry. Over a median of 61 months of treatment, 61% (31 of 51) reached a complete hematologic response, which required steady blood counts without phlebotomy, a normal-sized spleen and no blood clots; the median time to that response was 7.8 months. Steady blood counts alone were reached by 80% (41 of 51)[1][11].
Development history
Ropeginterferon alfa-2b carries the development code P1101, and PharmaEssentia sponsors its essential thrombocythemia trials[9][10]. The FDA received the first application on March 13, 2020 and issued a complete response letter on March 12, 2021. PharmaEssentia resubmitted on May 13, 2021, and the FDA approved Besremi for adults with polycythemia vera on November 12, 2021; the drug holds orphan drug designation for that use[3]. As a condition of approval, the FDA required an observational safety study looking at liver toxicity, heart problems and blood clots in people with polycythemia vera[3]. PharmaEssentia announced FDA approval of the BESREMi Pen for polycythemia vera on June 26, 2026[7]. In June 2026 PharmaEssentia announced that Taiwan had approved Besremi for essential thrombocythemia, which it called the first approval of Besremi for that use anywhere[8]. The FDA received the essential thrombocythemia application on October 30, 2025 and approved it on August 28, 2026; the drug holds orphan drug designation for that use too[4][5]. PharmaEssentia announced the approval on August 31, 2026 and called Besremi the first new FDA-approved treatment for essential thrombocythemia in nearly 3 decades[6].
Explore Polycythemia Vera and Essential Thrombocythemia trials
Other Polycythemia Vera & Essential Thrombocythemia treatments
For polycythemia vera, the FDA has approved ropeginterferon alfa-2b (Besremi, November 2021) for adults, ruxolitinib (Jakafi) for adults after hydroxyurea, and rusfertide (Mimrylo, August 2026) to treat erythrocytosis in adults with polycythemia vera. For essential thrombocythemia, Besremi was approved in August 2026, and anagrelide is approved for high platelet counts caused by myeloproliferative neoplasms; the 2 were compared in the SURPASS ET trial[1][12][13][14].
Common questions about Ropeginterferon alfa-2b-njft
▸What is Ropeginterferon alfa-2b-njft (Besremi)?
An injection under the skin, usually given every 2 weeks, approved by the FDA on November 12, 2021 for adults with polycythemia vera and on August 28, 2026 for adults with essential thrombocythemia. In the SURPASS ET trial against anagrelide, 37.4% of patients on Besremi had a durable response at both month 9 and month 12, against 3.6% on anagrelide. It carries a boxed warning for serious neuropsychiatric, autoimmune, ischemic and infectious disorders.
▸How does Ropeginterferon alfa-2b-njft work?
Interferon alfa is a protein the immune system makes naturally. Besremi is a lab-made version, interferon alfa-2b, with a chain of polyethylene glycol (PEG) attached to it[1]. It binds a receptor on bone marrow cells called the interferon alfa receptor (IFNAR), which switches on signaling enzymes called JAK1 and TYK2 and proteins called STATs that change which genes the cell turns on. The label says the exact way this calms the overactive marrow in polycythemia vera and essential thrombocythemia is not fully understood[1]. The goal of treatment is steady blood counts: hematocrit (the share of the blood made up of red cells) below 45%, platelets below 400 x 10^9/L and white blood cells below 10 x 10^9/L. In people with polycythemia vera, its half-life is about 7 days, and it is given every 2 weeks[1].
▸What are the side effects of Ropeginterferon alfa-2b-njft?
Besremi has a boxed warning. Interferon alfa products can cause or worsen fatal or life-threatening neuropsychiatric, autoimmune, ischemic (reduced blood flow) and infectious disorders, and treatment is stopped if these stay severe or keep getting worse. In many but not all cases they go away after stopping[1]. In the SURPASS ET trial in essential thrombocythemia, the most common side effects on Besremi vs anagrelide were raised liver enzymes (54% vs 14%), anemia (28% vs 30%), fever (26% vs 9%), a rise in a urine protein called beta-2 microglobulin (25% vs 4%), bacterial infection (24% vs 23%), itching (22% vs 19%) and weight loss (21% vs 6%). Bleeding was reported in 17% on Besremi and 38% on anagrelide, and headache in 15% vs 31%[1]. In the PEGINVERA trial in polycythemia vera, which had no comparison group and followed patients for up to 7.5 years, the most common were flu-like illness (59%), joint pain (47%), fatigue (47%), itching (45%), sore throat or common cold symptoms (43%), muscle and bone pain (41%) and headache (39%). Depression was reported in 20% and was the most common reason for stopping, in 8%[1]. Other warnings cover thyroid problems and high blood sugar, heart problems, low blood counts, allergic reactions, pancreatitis, colitis, lung problems, eye problems, high triglycerides, liver injury, kidney problems, tooth and gum problems, skin reactions, dizziness or sleepiness that can affect driving, and harm to an unborn baby[1].
▸How is Ropeginterferon alfa-2b-njft taken?
Besremi is injected under the skin of the lower belly, at least 2 inches from the belly button, or the top of the thigh. A healthcare professional, the patient or a caregiver can give it after training. It comes as a 500 mcg prefilled syringe or a 500 mcg prefilled pen, and both are set in 50 mcg steps[1]. For essential thrombocythemia, the first dose is 250 mcg, then 350 mcg at week 2, then 500 mcg every 2 weeks from week 4 on. If side effects occur, the dose is lowered in steps down to 100 mcg[1]. For polycythemia vera, the starting dose is 100 mcg every 2 weeks, raised by 50 mcg every 2 weeks up to 500 mcg until blood counts are steady. People switching from hydroxyurea start at 50 mcg alongside hydroxyurea, taper hydroxyurea during weeks 3 to 12 and stop it by week 13. After at least 1 year of steady counts on a stable dose, the PV schedule can stretch to every 4 weeks[1]. Phlebotomy may still be needed while the PV dose is being raised. Besremi is stored in the refrigerator at 36 to 46 degrees F, never frozen, and left in its carton at room temperature for 15 to 30 minutes before injecting[1].
▸Is Ropeginterferon alfa-2b-njft FDA approved?
Yes, Ropeginterferon alfa-2b-njft (Besremi) is FDA approved (2021) for the treatment of Polycythemia Vera and Essential Thrombocythemia.
▸What is Besremi used for?
Besremi (ropeginterferon alfa-2b-njft) treats adults with polycythemia vera and adults with essential thrombocythemia.
Polycythemia vera: The FDA approved it for adults with PV on November 12, 2021. PV is a blood cancer in which the bone marrow makes too many red blood cells.
Essential thrombocythemia: The FDA added adults with ET on August 28, 2026. ET is a related blood cancer in which the marrow makes too many platelets.
Genotype: PharmaEssentia says the ET approval covers adults regardless of genotype or disease status, including newly diagnosed patients.
Children: Safety and effectiveness in children have not been established.
Source: FDA label for Besremi, approved August 2026 and PharmaEssentia, August 31, 2026
▸How does Besremi work?
Besremi is a lab-made form of interferon alfa, a protein the immune system makes, with a PEG chain attached.
What it binds: It attaches to the interferon alfa receptor on bone marrow cells and switches on signals through enzymes called JAK1 and TYK2.
What is known: The label says the exact way it calms the overactive marrow in PV and ET is not fully understood.
What it aims for: Treatment aims for hematocrit below 45%, platelets below 400 x 10^9/L and white cells below 10 x 10^9/L.
How long it lasts: In PV its half-life is about 7 days, and it is given every 2 weeks.
▸What is the Besremi dose for essential thrombocythemia?
The ET dose builds up over 4 weeks to 500 mcg injected under the skin every 2 weeks.
Week 0: The first dose is 250 mcg.
Week 2: The dose goes up to 350 mcg.
Week 4 on: The maintenance dose is 500 mcg every 2 weeks.
Side effects: For moderate or severe side effects the dose can be paused or lowered in steps to 350, 250, 200, 150 and then 100 mcg.
Blood tests: Blood counts are checked every 2 weeks while the dose builds up and every 3 to 6 months after that.
▸What is the Besremi dose for polycythemia vera?
For PV, Besremi usually starts at 100 mcg every 2 weeks and goes up by 50 mcg every 2 weeks until blood counts are steady.
Maximum: The highest dose is 500 mcg.
Switching from hydroxyurea: Start at 50 mcg alongside hydroxyurea, lower the hydroxyurea during weeks 3 to 12 and stop it by week 13.
Every 4 weeks: After at least 1 year of steady counts on a stable dose, the schedule can stretch to every 4 weeks.
Phlebotomy: Blood draws to thin the blood may still be needed while the dose is being raised.
▸What are the side effects of Besremi?
Besremi carries a boxed warning that interferon alfa can cause or worsen serious neuropsychiatric, autoimmune, ischemic and infectious disorders.
In ET: In SURPASS ET the most common were raised liver enzymes (54% vs 14% on anagrelide), anemia (28% vs 30%), fever (26% vs 9%), bacterial infection (24% vs 23%), itching (22% vs 19%) and weight loss (21% vs 6%).
In PV: In PEGINVERA the most common were flu-like illness (59%), joint pain (47%), fatigue (47%), itching (45%) and headache (39%).
Mood: Depression was reported in 20% of PEGINVERA patients and led 8% to stop.
Other warnings: Thyroid, heart, liver, eye, lung, kidney, pancreas and colon problems, high triglycerides, low blood counts and harm to an unborn baby.
▸How does Besremi compare with anagrelide for essential thrombocythemia?
In the SURPASS ET trial, which compared the 2 directly, more patients on Besremi had a lasting response than on anagrelide.
Who was in it: The trial enrolled 174 adults with ET after hydroxyurea did not work well enough or could not be tolerated, 91 on Besremi and 83 on anagrelide, for 12 months.
Main result: A durable response at both month 9 and month 12 occurred in 37.4% on Besremi vs 3.6% on anagrelide.
Response meant: Platelets at or below 400 x 10^9/L, white cells below 9.5 x 10^9/L, no spleen growth and no bleeding or clotting events.
Blood clots: Among patients who completed the study, 1 of 82 on Besremi and 10 of 51 on anagrelide had a clotting event.
Side effects: Raised liver enzymes and fever were more common on Besremi, and bleeding, headache and diarrhea were more common on anagrelide.
▸Does Besremi work for CALR or MPL essential thrombocythemia?
The ET approval is not limited to a single mutation.
Company statement: PharmaEssentia says the approval covers adults with ET regardless of genotype.
Trial makeup: In SURPASS ET, 82% of patients had a JAK2 V617F mutation, 12% a CALR mutation and 1% an MPL mutation.
What is missing: The label does not report response rates by mutation.
What to do: Ask your hematologist how your own mutation results affect the choice.
Source: FDA label for Besremi, approved August 2026 and PharmaEssentia, August 31, 2026
▸Who should not take Besremi?
The label lists 5 groups who must not use Besremi.
Psychiatric history: People with a current or past severe psychiatric disorder, especially severe depression, suicidal thoughts or a suicide attempt.
Allergy: People allergic to interferons or to any ingredient in Besremi.
Liver: People with moderate or severe liver impairment (Child-Pugh B or C).
Autoimmune disease: People with active serious or untreated autoimmune disease.
Transplant: Transplant recipients taking drugs that suppress the immune system.
Also avoid: Kidney function (eGFR) below 30 mL/min and severe or unstable heart disease, such as uncontrolled high blood pressure or a recent heart attack or stroke.
▸Can you take Besremi while pregnant or breastfeeding?
Besremi can harm an unborn baby and may cause miscarriage, based on how it works and on animal studies.
Before starting: Women who could become pregnant need a pregnancy test.
Birth control: Use effective birth control during treatment and for at least 8 weeks after the last dose.
Breastfeeding: Do not breastfeed during treatment and for 8 weeks after the last dose.
Periods: Besremi can disrupt the menstrual cycle.
▸How much does Besremi cost, and is there copay help?
The FDA label does not list a price, and what you pay depends on your insurance.
Commercial insurance: Eligible patients whose commercial plan covers Besremi may pay as little as $0 per month through the PharmaEssentia SOURCE Copay and Coinsurance Assistance Program.
Government insurance: Medicare, Medicaid, TRICARE, VA and other federal or state plans are not eligible for the copay program.
No coverage: The Patient Assistance Program may provide Besremi at no cost to eligible people who are uninsured or whose plan does not cover it, based on financial criteria the program page does not list.
Phone: Call PharmaEssentia SOURCE at 1-800-700-5053, Monday to Friday, 8 AM to 8 PM ET.
Source: PharmaEssentia SOURCE financial assistance and PharmaEssentia SOURCE
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- U.S. National Library of Medicine, DailyMed. BESREMi (ropeginterferon alfa-2b-njft) injection, for subcutaneous use: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9583405d-53a0-49dc-88eb-5e6384ebabcb
- U.S. Food and Drug Administration · 2026-09-01. BESREMi prescribing information approved with supplement 13 (essential thrombocythemia). https://www.accessdata.fda.gov/drugsatfda_docs/label/2026/761166s013lbl.pdf
- U.S. Food and Drug Administration · 2021-11-12. BLA 761166 approval letter (polycythemia vera). https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2021/761166Orig1s000ltr.pdf
- U.S. Food and Drug Administration · 2026-08-28. BLA 761166/S-013 supplement approval letter (essential thrombocythemia). https://www.accessdata.fda.gov/drugsatfda_docs/appletter/2026/761166Orig1s03ltr.pdf
- U.S. Food and Drug Administration · 2026-08-31. FDA approves treatment for essential thrombocythemia. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-treatment-essential-thrombocythemia
- PharmaEssentia USA · 2026-08-31. FDA Approves PharmaEssentia's BESREMi (ropeginterferon alfa-2b-njft) for Adults with Essential Thrombocythemia, A Rare Blood Cancer. https://us.pharmaessentia.com/fda-approves-pharmaessentias-besremi-ropeginterferon-alfa-2b-njft-for-adults-with-essential-thrombocythemia-a-rare-blood-cancer/
- PharmaEssentia USA · 2026-06-26. PharmaEssentia Announces FDA Approval and U.S. Launch of BESREMi Pen (ropeginterferon alfa-2b-njft) for Polycythemia Vera. https://us.pharmaessentia.com/pharmaessentia-announces-fda-approval-and-u-s-launch-of-besremi-pen-ropeginterferon-alfa-2b-njft-for-polycythemia-vera/
- PharmaEssentia USA · 2026-06-10. PharmaEssentia Announces Taiwan Approval of BESREMi for Essential Thrombocythemia, Marking First Global Approval in ET. https://us.pharmaessentia.com/pharmaessentia-announces-taiwan-approval-of-besremi-for-essential-thrombocythemia-marking-first-global-approval-in-et/
- ClinicalTrials.gov. Ropeginterferon Alfa-2b (P1101) vs. Anagrelide in Essential Thrombocythemia Patients With Hydroxyurea Resistance or Intolerance (SURPASS ET). https://clinicaltrials.gov/study/NCT04285086
- ClinicalTrials.gov. A Single-arm, Multicenter Study to Assess the Efficacy, Safety, and Tolerability of P1101 in Adults With ET (EXCEED ET). https://clinicaltrials.gov/study/NCT05482971
- ClinicalTrials.gov. Safety Study of Pegylated Interferon Alpha 2b to Treat Polycythemia Vera (PEGINVERA). https://clinicaltrials.gov/study/NCT01193699
- U.S. National Library of Medicine, DailyMed. JAKAFI (ruxolitinib) tablets: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f1c82580-87ae-11e0-bc84-0002a5d5c51b
- U.S. National Library of Medicine, DailyMed. MIMRYLO (rusfertide) for injection, for subcutaneous use: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=101aff01-31ed-4841-a8b6-0a5a8503189b
- U.S. National Library of Medicine, DailyMed. Anagrelide capsules: prescribing information. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=56b3959d-4b6b-413f-b753-9d4c20c07466
- PharmaEssentia USA. PharmaEssentia SOURCE financial assistance. https://pharmaessentiasource.com/financial-assistance/