IMPORTANT SAFETY INFORMATION AND INDICATIONS

Risk of Progression of Myelodysplastic Syndromes to Acute Myelogenous Leukemia

In Nplate^® (romiplostim) clinical trials of patients with myelodysplastic syndromes (MDS) and severe thrombocytopenia, progression from MDS to acute myelogenous leukemia (AML) has been observed.

Nplate^® is not indicated for the treatment of thrombocytopenia due to MDS or any cause of thrombocytopenia other than ITP.

Thrombotic/Thromboembolic Complications

Thrombotic/thromboembolic complications have resulted from increases in platelet counts with Nplate^® use in the ITP population, including deep vein thrombosis (1.4%), pulmonary embolism (1.2%) and myocardial infarction (0.8%). Other thrombotic events including transient ischemic attack have been reported. These events have occurred regardless of platelet counts. Portal vein thrombosis has been reported in patients both with and without chronic liver disease receiving Nplate^®.

To minimize the risk for thrombotic/thromboembolic complications, do not use Nplate^® in an attempt to normalize platelet counts. Follow the dose adjustment guidelines to achieve and maintain a platelet count of ≥ 50 x 10⁹/L.

Loss of Response to Nplate^®

Hyporesponsiveness or failure to maintain a platelet response with Nplate^® should prompt a search for causative factors, including neutralizing antibodies to Nplate^®.

Discontinue Nplate^® if the platelet count does not increase to a level sufficient to avoid clinically important bleeding after 4 weeks at the highest weekly dose of 10 mcg/kg.

Adverse Reactions

In the placebo-controlled trials, headache was the most commonly reported adverse drug reaction, occurring in 35% of patients receiving Nplate^® and 32% of patients receiving placebo. Adverse drug reactions with a ≥ 5% higher patient incidence in Nplate^® versus placebo were Arthralgia (26%, 20%), Dizziness (17%, 0%), Insomnia (16%, 7%), Myalgia (14%, 2%), Pain in Extremity (13%, 5%), Abdominal Pain (11%, 0%), Shoulder Pain (8%, 0%), Dyspepsia (7%, 0%), and Paresthesia (6%, 0%).

The safety profile of Nplate^® was similar across patients, regardless of ITP duration. The following adverse reactions (at least 5% incidence and at least 5% more frequent with Nplate^® compared with placebo or standard of care) occurred in Nplate^® patients with ITP duration up to 12 months: bronchitis, sinusitis, vomiting, arthralgia, myalgia, headache, dizziness, diarrhea, upper respiratory tract infection, cough, nausea and oropharyngeal pain. The adverse reaction of thrombocytosis occurred with an incidence of 2% in adults with ITP duration up to 12 months.

Nplate^® administration may increase the risk for development or progression of reticulin fiber formation within the bone marrow. This formation may improve upon discontinuation of Nplate^®. In a clinical trial, one patient with ITP and hemolytic anemia developed marrow fibrosis with collagen during Nplate^® therapy.

INDICATION

Nplate^® is a thrombopoietin receptor agonist indicated for the treatment of thrombocytopenia in adult patients with immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy.

Nplate^® is not indicated for the treatment of thrombocytopenia due to myelodysplastic syndrome (MDS) or any cause of thrombocytopenia other than ITP. Nplate^® should be used only in patients with ITP whose degree of thrombocytopenia and clinical condition increase the risk for bleeding. Nplate^® should not be used in an attempt to normalize platelet counts.

Please see full Prescribing Information and Medication Guide.

STUDY DESIGN

Nplate^® was studied in a 52-week, open-label,
single-arm, phase 2 trial of 75 adults with ITP for
≤ 6 months who had an insufficient response to first-line ITP treatment.²

The primary endpoint of the study was the cumulative number of months in which patients achieved a platelet response: 61% of patients sustained platelet counts
≥ 50 x 10⁹/L for ≥ 11 months (n = 46/75). Platelet response was defined as a platelet count ≥ 50 x 10⁹/L:5.56%, 47.22%, and 61.11% of patients responded by weeks 1, 2, and 3, respectively.⁷

Treatment-free remission was a secondary endpoint defined as maintaining every platelet count at
≥ 50 x 10⁹/L for at least 6 months in the absence of any ITP treatment, and occurred in 32% (n = 24/75) of patients.²

SAFETY DATA

Based on an open-label, single-arm, extension study of 291 adults with chronic ITP who had at least one dose of Nplate^®. Subjects could enter any time during the
277-week period. Mean treatment duration was 110 weeks.⁴

Study results: AEs did not increase in frequency or type with longer Nplate^® drug exposure.⁴

Primary assessment/incidence: Serious treatment-related AEs 8% (24/291), thrombotic events 6.5% (19/291), bone marrow reticulin increase 1.4% (4/291), neutralizing antibody formation <1% (2/291), and deaths 5% (16/291) were the most common AEs in the study.⁴

AE, adverse effect; ITP, immune thrombocytopenia; OOP, out-of-pocket; TFR, treatment-free remission.

References: 1. Nplate^® (romiplostim) prescribing information, Amgen. 2. Newland A, Godeau B, Priego V, et al. Remission and platelet responses with romiplostim in primary immune thrombocytopenia: final results from a phase 2 study. Br J Haematol. 2016;172(2):262-273.
3. Data on file, Amgen; [1]; 2024. 4. Kuter DJ, Bussel JB, Newland A, et al. Long-term treatment with romiplostim in patients with chronic immune thrombocytopenia: safety and efficacy. Br J Haematol. 2013;161:411– 423. 5. Data on file. Amgen; Nplate^® - coverage from MMIT: August 2025. 6. Data on file. Amgen: Nplate^® IQVIA LAAD 2023 and 2024 OOP cost analysis Medicare Commercial combined ALL: 2025. 7. Data on file, Amgen; [4]; 2019.

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