Nplate 250 micrograms powder and solvent for solution for injection (Reconstitution Pack)

Summary of Product Characteristics Updated 27-Feb-2018 | Amgen Ltd

1. Name of the medicinal product

Nplate 250 micrograms powder and solvent for solution for injection

Nplate 500 micrograms powder and solvent for solution for injection

2. Qualitative and quantitative composition

Nplate 250 micrograms powder and solvent for solution for injection

Each vial contains 250 mcg of romiplostim. After reconstitution, a deliverable volume of 0.5 mL solution contains 250 mcg of romiplostim (500 mcg/mL). An additional overfill is included in each vial to ensure that 250 mcg of romiplostim can be delivered.

Nplate 500 micrograms powder and solvent for solution for injection

Each vial contains 500 mcg of romiplostim. After reconstitution, a deliverable volume of 1 mL solution contains 500 mcg of romiplostim (500 mcg/mL). An additional overfill is included in each vial to ensure that 500 mcg of romiplostim can be delivered.

Romiplostim is produced by recombinant DNA technology in Escherichia coli (E. coli).

For the full list of excipients, see section 6.1.

3. Pharmaceutical form

Powder and solvent for solution for injection (powder for injection).

The powder is white.

The solvent is a clear colourless liquid.

4. Clinical particulars
4.1 Therapeutic indications

Nplate is indicated for adult chronic immune (idiopathic) thrombocytopenic purpura (ITP) patients who are refractory to other treatments (e.g. corticosteroids, immunoglobulins) (see sections 4.2 and 5.1).

4.2 Posology and method of administration

Treatment should remain under the supervision of a physician who is experienced in the treatment of haematological diseases.

Posology

Nplate should be administered once weekly as a subcutaneous injection.

Initial dose

The initial dose of romiplostim is 1 mcg/kg based on actual body weight.

Dose calculation

Initial or subsequent once weekly dose:

Weight* in kg x Dose in mcg/kg = Individual patient dose in mcg

Volume to administer:

Example:

75 kg patient is initiated at 1 mcg/kg of romiplostim.

The individual patient dose =

75 kg x 1 mcg/kg = 75 mcg

The corresponding amount of Nplate solution to inject =

*Actual body weight at initiation of treatment should always be used when calculating dose of romiplostim. Future dose adjustments are based on changes in platelet counts only and made in 1 mcg/kg increments (see table below).

Dose adjustments

A subject's actual body weight at initiation of therapy should be used to calculate dose. The once weekly dose of romiplostim should be increased by increments of 1 mcg/kg until the patient achieves a platelet count ≥ 50 x 109/L. Platelet counts should be assessed weekly until a stable platelet count (≥ 50 x 109/L for at least 4 weeks without dose adjustment) has been achieved. Platelet counts should be assessed monthly thereafter. A maximum once weekly dose of 10 mcg/kg should not be exceeded.

Adjust the dose as follows:

Platelet count

(x 109/L)

Action

< 50

Increase once weekly dose by 1 mcg/kg

> 150 for two consecutive weeks

Decrease once weekly dose by 1 mcg/kg

> 250

Do not administer, continue to assess the platelet count weekly

After the platelet count has fallen to < 150 x 109/L, resume dosing with once weekly dose reduced by 1 mcg/kg

Due to the interindividual variable platelet response, in some patients platelet count may abruptly fall below 50 x 109/L after dose reduction or treatment discontinuation. In these cases, if clinically appropriate, higher cut-off levels of platelet count for dose reduction (200 x 109/L) and treatment interruption (400 x 109/L) may be considered according to medical judgement.

A loss of response or failure to maintain a platelet response with romiplostim within the recommended dosing range should prompt a search for causative factors (see section 4.4, loss of response to romiplostim).

Treatment discontinuation

Treatment with romiplostim should be discontinued if the platelet count does not increase to a level sufficient to avoid clinically important bleeding after four weeks of romiplostim therapy at the highest weekly dose of 10 mcg/kg.

Patients should be clinically evaluated periodically and continuation of treatment should be decided on an individual basis by the treating physician, and in non-splenectomised patients this should include evaluation relative to splenectomy. The reoccurrence of thrombocytopenia is likely upon discontinuation of treatment (see section 4.4).

Elderly patients (≥ 65 years)

No overall differences in safety or efficacy have been observed in patients < 65 and ≥ 65 years of age (see section 5.1). Although based on these data no adjustment of the dosing regimen is required for older patients, care is advised considering the small number of elderly patients included in the clinical trials so far.

Paediatric population

The safety and efficacy of romiplostim 250/500 mcg powder and solvent for solution for injection, also used for self-administration in eligible adult patients, have not been established in patients aged under 18 years. Self-administration of romiplostim is not allowed for paediatric patients. No data are available. Other pharmaceutical forms/strengths may be more appropriate for administration to this population.

Patients with hepatic Impairment

Romiplostim should not be used in patients with moderate to severe hepatic impairment (Child-Pugh score ≥ 7) unless the expected benefit outweighs the identified risk of portal venous thrombosis in patients with thrombocytopenia associated to hepatic insufficiency treated with thrombopoietin (TPO) agonists (see section 4.4).

If the use of romiplostim is deemed necessary, platelet count should be closely monitored to minimise the risk of thromboembolic complications.

Patients with renal impairment

No formal clinical trials have been conducted in these patient populations. Nplate should be used with caution in these populations.

Method of administration

For subcutaneous use.

After reconstitution of the powder, Nplate solution for injection is administered subcutaneously. The injection volume may be very small. Caution should be used during preparation of Nplate in calculating the dose and reconstitution with the correct volume of sterile water for injection. Special care should be taken to ensure that the appropriate volume of Nplate is withdrawn from the vial for subcutaneous administration – a syringe with graduations of 0.01 mL should be used.

Patients who have a stable platelet count ≥ 50 x 109/L for at least 4 weeks without dose adjustment may, at the discretion of the supervising physician, self-administer Nplate solution for injection. Patients eligible for self-administration of Nplate should be trained in these procedures.

After the first 4 weeks of self-administration, the patient should again be supervised while reconstituting and administering Nplate. Only patients who demonstrate the ability to reconstitute and self-administer Nplate are allowed to continue doing so.

For instructions on reconstitution and administration of the medicinal product, see section 6.6.

4.3 Contraindications

Hypersensitivity to the active substance or to any of the excipients listed in section 6.1 or to E. coli derived proteins.

4.4 Special warnings and precautions for use

Reoccurrence of thrombocytopenia and bleeding after cessation of treatment

Thrombocytopenia is likely to reoccur upon discontinuation of treatment with romiplostim. There is an increased risk of bleeding if romiplostim treatment is discontinued in the presence of anticoagulants or anti-platelet agents. Patients should be closely monitored for a decrease in platelet count and medically managed to avoid bleeding upon discontinuation of treatment with romiplostim. It is recommended that, if treatment with romiplostim is discontinued, ITP treatment be restarted according to current treatment guidelines. Additional medical management may include cessation of anticoagulant and/or antiplatelet therapy, reversal of anticoagulation, or platelet support.

Increased bone marrow reticulin

Increased bone marrow reticulin is believed to be a result of TPO receptor stimulation, leading to an increased number of megakaryocytes in the bone marrow, which may subsequently release cytokines. Increased reticulin may be suggested by morphological changes in the peripheral blood cells and can be detected through bone marrow biopsy. Therefore, examinations for cellular morphological abnormalities using peripheral blood smear and complete blood count (CBC) prior to and during treatment with romiplostim are recommended. See section 4.8 for information on the increases of reticulin observed in romiplostim clinical trials.

If a loss of efficacy and abnormal peripheral blood smear is observed in patients, administration of romiplostim should be discontinued, a physical examination should be performed, and a bone marrow biopsy with appropriate staining for reticulin should be considered. If available, comparison to a prior bone marrow biopsy should be made. If efficacy is maintained and abnormal peripheral blood smear is observed in patients, the physician should follow appropriate clinical judgment, including consideration of a bone marrow biopsy, and the risk-benefit of romiplostim and alternative ITP treatment options should be re-assessed.

Thrombotic/thromboembolic complications

Platelet counts above the normal range present a risk for thrombotic/thromboembolic complications. The incidence of thrombotic/thromboembolic events observed in clinical trials was 6.0% with romiplostim and 3.6% with placebo. Caution should be used when administering romiplostim to patients with known risk factors for thromboembolism including but not limited to inherited (e.g. Factor V Leiden) or acquired risk factors (e.g. ATIII deficiency, antiphospholipid syndrome), advanced age, patients with prolonged periods of immobilisation, malignancies, contraceptives and hormone replacement therapy, surgery/trauma, obesity and smoking.

Cases of thromboembolic events (TEEs), including portal vein thrombosis, have been reported in patients with chronic liver disease receiving romiplostim. Romiplostim should be used with caution in these populations. Dose adjustment guidelines should be followed (see section 4.2).

Medication Errors

Medication errors including overdose and underdose have been reported in patients receiving Nplate, dose calculation and dose adjustment guidelines should be followed (see section 4.2).

Overdose may result in an excessive increase in platelet counts associated with thrombotic/thromboembolic complications. If the platelet counts are excessively increased, discontinue Nplate and monitor platelet counts. Reinitiate treatment with Nplate in accordance with dosing and administration recommendations. Underdose may result in lower than expected platelet counts and potential for bleeding. Platelet counts should be monitored in patients receiving Nplate (see sections 4.2, 4.4 and 4.9).

Progression of existing Myelodysplastic Syndromes (MDS)

A positive benefit/risk for romiplostim is only established for the treatment of thrombocytopenia associated with chronic ITP and romiplostim must not be used in other clinical conditions associated with thrombocytopenia.

The diagnosis of ITP in adults and elderly patients should have been confirmed by the exclusion of other clinical entities presenting with thrombocytopenia, in particular the diagnosis of MDS must be excluded. A bone marrow aspirate and biopsy should normally have been done over the course of the disease and treatment, particularly in patients over 60 years of age, for those with systemic symptoms or abnormal signs such as increased peripheral blast cells.

In clinical studies of treatment with romiplostim in patients with MDS, cases of transient increases in blast cell counts were observed and cases of MDS disease progression to AML were reported. In a randomised placebo-controlled trial in MDS subjects, treatment with romiplostim was prematurely stopped due to a numerical excess of disease progression to AML and an increase in circulating blasts greater than 10% in patients receiving romiplostim. Of the cases of MDS disease progression to AML that were observed, patients with RAEB-1 classification of MDS at baseline were more likely to have disease progression to AML compared to lower risk MDS.

Romiplostim must not be used for the treatment of thrombocytopenia due to MDS or any other cause of thrombocytopenia other than ITP outside of clinical trials.

Loss of response to romiplostim

A loss of response or failure to maintain a platelet response with romiplostim treatment within the recommended dosing range should prompt a search for causative factors, including immunogenicity (see section 4.8) and increased bone marrow reticulin (see above).

Effects of romiplostim on red and white blood cells

Alterations in red (decrease) and white (increase) blood cell parameters have been observed in non-clinical toxicology studies (rat and monkey) as well as in ITP patients. Concurrent anaemia and leucocytosis (within a 4-week window) may occur in patients regardless of splenectomy status, but have been seen more often in patients who have had a prior splenectomy. Monitoring of these parameters should be considered in patients treated with romiplostim.

4.5 Interaction with other medicinal products and other forms of interaction

No interaction studies have been performed. The potential interactions of romiplostim with co-administered medicinal products due to binding to plasma proteins remain unknown.

Medicinal products used in the treatment of ITP in combination with romiplostim in clinical trials included corticosteroids, danazol, and/or azathioprine, intravenous immunoglobulin (IVIG), and anti-D immunoglobulin. Platelet counts should be monitored when combining romiplostim with other medicinal products for the treatment of ITP in order to avoid platelet counts outside of the recommended range (see section 4.2).

Corticosteroids, danazol, and azathioprine use may be reduced or discontinued when given in combination with romiplostim (see section 5.1). Platelet counts should be monitored when reducing or discontinuing other ITP treatments in order to avoid platelet counts below the recommended range (see section 4.2).

4.6 Fertility, pregnancy and lactation

Pregnancy

There are no or limited amount of data from the use of romiplostim in pregnant women.

Studies in animals have shown that romiplostim crossed the placenta and increased foetal platelet counts. Post implantation loss and a slight increase in peri-natal pup mortality also occurred in animal studies (see section 5.3).

Romiplostim is not recommended during pregnancy and in women of childbearing potential not using contraception.

Breast-feeding

It is unknown whether romiplostim/metabolites are excreted in human milk. A risk to the newborns/infants cannot be excluded. A decision must be made whether to discontinue breast-feeding or to discontinue/abstain from romiplostim therapy taking into account the benefit of breast feeding for the child and the benefit of therapy for the woman.

Fertility

There is no data available on fertility.

4.7 Effects on ability to drive and use machines

Nplate has moderate influence on the ability to drive and use machines. In clinical trials, mild to moderate, transient bouts of dizziness were experienced by some patients.

4.8 Undesirable effects

Summary of the safety profile

Based on an analysis of all adult ITP patients receiving romiplostim in 4 controlled and 5 uncontrolled clinical trials, the overall subject incidence of all adverse reactions for romiplostim-treated subjects was 91.5% (248/271). The mean duration of exposure to romiplostim in this study population was 50 weeks.

The most serious adverse reactions that may occur during Nplate treatment include: reoccurrence of thrombocytopenia and bleeding after cessation of treatment, increased bone marrow reticulin, thrombotic/thromboembolic complications, medication errors and progression of existing MDS to AML. The most common adverse reactions observed include hypersensitivity reactions (including cases of rash, urticaria and angioedema) and headache.

Tabulated list of adverse reactions

Frequencies are defined as: very common (≥ 1/10), common (≥ 1/100 to < 1/10), uncommon (≥ 1/1,000 to < 1/100), rare (≥ 1/10,000 to < 1/1,000); very rare (< 1/10,000) and not known (cannot be estimated from the available data). Within each MedDRA system organ class and frequency grouping, undesirable effects are presented in order of decreasing incidence.

MedDRA system organ class

Very common

Common

Uncommon

Infections and infestations

Upper respiratory tract infection

Gastroenteritis

Influenza

Localised infection

Nasopharyngitis

Neoplasms benign, malignant and unspecified (including cysts and polyps)

Multiple myeloma

Myelofibrosis

Blood and lymphatic system disorders

Bone marrow disorder*

Thrombocytopenia*

Anaemia

Aplastic anaemia

Bone marrow failure

Leucocytosis

Splenomegaly

Thrombocythaemia

Platelet count increased

Platelet count abnormal

Immune system disorder

Hypersensitivity**

Angioedema

Metabolism and nutrition disorders

Alcohol intolerance

Anorexia

Decreased appetite

Dehydration

Gout

Psychiatric disorders

Insomnia

Depression

Abnormal dreams

Nervous system disorders

Headache

Dizziness

Migraine

Paraesthesia

Clonus

Dysgeusia

Hypoaesthesia

Hypogeusia

Neuropathy peripheral

Transverse sinus thrombosis

Eye disorders

Conjunctival haemorrhage

Accommodation disorder

Blindness

Eye disorder

Eye pruritus

Lacrimation increased

Papilloedema

Visual disturbances

Ear and labyrinth disorders

Vertigo

Cardiac disorders

Palpitations

Myocardial infarction

Heart rate increased

Vascular disorders

Flushing

Deep vein thrombosis

Hypotension

Peripheral embolism

Peripheral ischaemia

Phlebitis

Thrombophlebitis superficial

Thrombosis

Erythromelalgia

Respiratory, thoracic and mediastinal disorders

Pulmonary embolism*

Cough

Rhinorrhoea

Dry throat

Dyspnoea

Nasal congestion

Painful respiration

Gastrointestinal disorders

Nausea

Diarrhoea

Abdominal pain

Constipation

Dyspepsia

Vomiting

Rectal haemorrhage

Breath odour

Dysphagia

Gastro-oesophageal reflux disease

Haematochezia

Mouth haemorrhage

Stomach discomfort

Stomatitis

Tooth discolouration

Hepatobiliary disorders

Portal vein thrombosis

Increase in transaminase

Skin and subcutaneous tissue disorders

Pruritus

Ecchymosis

Rash

Alopecia

Photosensitivity reaction

Acne

Dermatitis contact

Dry skin

Eczema

Erythema

Exfoliative rash

Hair growth abnormal

Prurigo

Purpura

Rash papular

Rash pruritic

Skin nodule

Skin odour abnormal

Urticaria

Musculoskeletal and connective tissue disorders

Arthralgia

Myalgia

Muscle spasms

Pain in extremity

Back pain

Bone pain

Muscle tightness

Muscular weakness

Shoulder pain

Muscle twitching

Renal and urinary disorders

Protein urine present

Reproductive system and breast disorders

Vaginal haemorrhage

General disorders and administration site conditions

Fatigue

Oedema peripheral

Influenza like illness

Pain

Asthenia

Pyrexia

Chills

Injection site reaction

Injection site haemorrhage

Chest pain

Irritability

Malaise

Face oedema

Feeling hot

Feeling jittery

Investigations

Blood pressure increased

Blood lactate dehydrogenase increased

Body temperature increased

Weight decreased

Weight increased

Injury, poisoning and procedural complications

Contusion

* see section 4.4

** Hypersensitivity reactions including cases of rash, urticaria, and angioedema

Description of selected adverse reactions

In addition the reactions listed below have been deemed to be related to romiplostim treatment.

Thrombocytosis

Based on an analysis of all adult ITP patients receiving romiplostim in 4 controlled and 5 uncontrolled clinical trials, 3 events of thrombocytosis were reported, n = 271. No clinical sequelae were reported in association with the elevated platelet counts in any of the 3 subjects.

Thrombocytopenia after cessation of treatment

Based on an analysis of all adult ITP patients receiving romiplostim in 4 controlled and 5 uncontrolled clinical trials, 4 events of thrombocytopenia after cessation of treatment were reported, n = 271 (see section 4.4).

Progression of existing Myelodysplastic Syndromes (MDS)

In a randomised placebo-controlled trial in MDS subjects treatment with romiplostim was prematurely stopped due to a numerical increase in cases of MDS disease progression to AML and transient increases in blast cell counts in patients treated with romiplostim compared to placebo. Of the cases of MDS disease progression to AML that were observed, patients with RAEB-1 classification of MDS at baseline were more likely to have disease progression to AML (see section 4.4). Overall survival was similar to placebo.

Increased bone marrow reticulin

In clinical trials, romiplostim treatment was discontinued in 4 of the 271 patients because of bone marrow reticulin deposition. In 6 additional patients reticulin was observed upon bone marrow biopsy (see section 4.4).

Immunogenicity

Clinical trials in adult ITP patients examined antibodies to romiplostim.

While 5.8% and 3.9% of the subjects were positive for developing binding antibodies to romiplostim and TPO respectively, only 2 subjects (0.4%) were positive for neutralising antibodies to romiplostim but these antibodies did not cross react with endogenous TPO. Both subjects tested negative for neutralising antibodies to romiplostim at 4 months after the end of dosing. The incidence of pre-existing antibodies to romiplostim and TPO was 8.0% and 5.4%, respectively.

As with all therapeutic proteins, there is a potential for immunogenicity. If formation of neutralising antibodies is suspected, contact the local representative of the Marketing Authorisation Holder (see section 6 of the Package Leaflet) for antibody testing.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via:

United Kingdom

Yellow Card Scheme

Website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store

Ireland

HPRA Pharmacovigilance

Earlsfort Terrace

IRL - Dublin 2

Tel: +353 1 6764971

Fax: +353 1 6762517

Website: www.hpra.ie

e-mail: [email protected]

4.9 Overdose

No adverse effects were seen in rats given a single dose of 1,000 mcg/kg or in monkeys after repeated administration of romiplostim at 500 mcg/kg (100 or 50 times the maximum clinical dose of 10 mcg/kg, respectively).

In the event of overdose, platelet counts may increase excessively and result in thrombotic/thromboembolic complications. If the platelet counts are excessively increased, discontinue Nplate and monitor platelet counts. Reinitiate treatment with Nplate in accordance with dosing and administration recommendations (see sections 4.2 and 4.4).

5. Pharmacological properties
5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Antihaemorrhagics, other systemic haemostatics, ATC code: B02BX04

Mechanism of action

Romiplostim is an Fc-peptide fusion protein (peptibody) that signals and activates intracellular transcriptional pathways via the TPO receptor (also known as cMpl) to increase platelet production. The peptibody molecule is comprised of a human immunoglobulin IgG1 Fc domain, with each single-chain subunit covalently linked at the C-terminus to a peptide chain containing 2 TPO receptor-binding domains.

Romiplostim has no amino acid sequence homology to endogenous TPO. In pre-clinical and clinical trials no anti-romiplostim antibodies cross reacted with endogenous TPO.

Clinical efficacy and safety

The safety and efficacy of romiplostim have been evaluated for up to 3 years of continuous treatment. In clinical trials, treatment with romiplostim resulted in dose-dependent increases in platelet count. Time to reach the maximum effect on platelet count is approximately 10-14 days, and is independent of the dose. After a single subcutaneous dose of 1 to 10 mcg/kg romiplostim in ITP patients, the peak platelet count was 1.3 to 14.9 times greater than the baseline platelet count over a 2 to 3 week period and the response was variable among patients. The platelet counts of ITP patients who received 6 weekly doses of 1 or 3 mcg/kg of romiplostim were within the range of 50 to 450 x 109/L for most patients. Of the 271 patients who received romiplostim in ITP clinical trials, 55 (20%) were age 65 and over, and 27 (10%) were 75 and over. No overall differences in safety or efficacy have been observed between older and younger patients in the placebo-controlled studies.

Results from pivotal placebo-controlled studies

The safety and efficacy of romiplostim was evaluated in two placebo-controlled, double-blind studies in adults with ITP who had completed at least one treatment prior to study entry and are representative of the entire spectrum of such ITP patients.

Study S1 (212) evaluated patients who were non-splenectomised and had an inadequate response or were intolerant to prior therapies. Patients had been diagnosed with ITP for approximately 2 years at the time of study entry. Patients had a median of 3 (range, 1 to 7) treatments for ITP prior to study entry. Prior treatments included corticosteroids (90% of all patients), immunoglobulins (76%), rituximab (29%), cytotoxic therapies (21%), danazol (11%), and azathioprine (5%). Patients had a median platelet count of 19 x 109/L at study entry.

Study S2 (105) evaluated patients who were splenectomised and continued to have thrombocytopenia. Patients had been diagnosed with ITP for approximately 8 years at the time of study entry. In addition to a splenectomy, patients had a median of 6 (range, 3 to 10) treatments for ITP prior to study entry. Prior treatments included corticosteroids (98% of all patients), immunoglobulins (97%), rituximab (71%), danazol (37%), cytotoxic therapies (68%), and azathioprine (24%). Patients had a median platelet count of 14 x 109/L at study entry.

Both studies were similarly designed. Patients (≥ 18 years) were randomised in a 2:1 ratio to receive a starting dose of romiplostim 1 mcg/kg or placebo. Patients received single subcutaneous weekly injections for 24 weeks. Doses were adjusted to maintain (50 to 200 x 109/L) platelet counts. In both studies, efficacy was determined by an increase in the proportion of patients who achieved a durable platelet response. The median average weekly dose for splenectomised patients was 3 mcg/kg and for non-splenectomised patients was 2 mcg/kg.

A significantly higher proportion of patients receiving romiplostim achieved a durable platelet response compared to patients receiving placebo in both studies. Following the first 4-weeks of study romiplostim maintained platelet counts ≥ 50 x 109/L in between 50% to 70% of patients during the 6 month treatment period in the placebo-controlled studies. In the placebo group, 0% to 7% of patients were able achieve a platelet count response during the 6 months of treatment. A summary of the key efficacy endpoints is presented below.

Summary of key efficacy results from placebo-controlled studies

Study 1

non-splenectomised patients

Study 2

splenectomised patients

Combined studies 1 & 2

romiplostim

(n = 41)

Placebo

(n = 21)

romiplostim

(n = 42)

Placebo

(n = 21)

romiplostim

(n = 83)

Placebo

(n = 42)

No. (%) patients with durable platelet responsea

25 (61%)

1 (5%)

16 (38%)

0 (0%)

41 (50%)

1 (2%)

(95% CI)

(45%, 76%)

(0%, 24%)

(24%, 54%)

(0%, 16%)

(38%, 61%)

(0%, 13%)

p-value

< 0.0001

0.0013

< 0.0001

No. (%) patients with overall platelet responseb

36 (88%)

3 (14%)

33 (79%)

0 (0%)

69 (83%)

3 (7%)

(95% CI)

(74%, 96%)

(3%, 36%)

(63%, 90%)

(0%, 16%)

(73%, 91%)

(2%, 20%)

p-value

< 0.0001

< 0.0001

< 0.0001

Mean no. weeks with platelet responsec

15

1

12

0

14

1

(SD)

3.5

7.5

7.9

0.5

7.8

2.5

p-value

< 0.0001

< 0.0001

< 0.0001

No. (%) patients requiring rescue therapiesd

8(20%)

13 (62%)

11 (26%)

12 (57%)

19 (23%)

25 (60%)

(95% CI)

(9%, 35%)

(38%, 82%)

(14%, 42%)

(34%, 78%)

(14%, 33%)

(43%, 74%)

p-value

0.001

0.0175

< 0.0001

No. (%) patients with durable platelet response with stable dosee

21 (51%)

0 (0%)

13 (31%)

0 (0%)

34 (41%)

0 (0%)

(95% CI)

(35%, 67%)

(0%, 16%)

(18%, 47%)

(0%, 16%)

(30%, 52%)

(0%, 8%)

p-value

0.0001

0.0046

< 0.0001

a Durable platelet response was defined as weekly platelet count ≥ 50 x 109/L for 6 or more times for study weeks 18-25 in the absence of rescue therapies any time during the treatment period.

b Overall platelet response is defined as achieving durable or transient platelet responses. Transient platelet response was defined as weekly platelet count ≥ 50 x 109/L for 4 or more times during study weeks 2-25 but without durable platelet response. Patient may not have a weekly response within 8 weeks after receiving any rescue medicinal products.

c Number of weeks with platelet response is defined as number of weeks with platelet counts ≥ 50 x 109/L during study weeks 2-25. Patient may not have a weekly response within 8 weeks after receiving any rescue medicinal products.

d Rescue therapies defined as any therapy administered to raise platelet counts. Patients requiring rescue medicinal products were not considered for durable platelet response. Rescue therapies allowed in the study were IVIG, platelet transfusions, anti-D immunoglobulin, and corticosteroids.

e Stable dose defined as dose maintained within ± 1 mcg/kg during the last 8 weeks of treatment.

Results of studies compared to standard of care (SOC) in non-splenectomised patients

Study S3 (131) was an open-label randomised 52 week trial in subjects who received romiplostim or medical standard of care (SOC) treatment. This study evaluated non-splenectomised patients with ITP and platelet counts < 50 x 109/L. Romiplostim was administered to 157 subjects by subcutaneous (SC) injection once weekly starting at a dose of 3 mcg/kg, and adjusted throughout the study within a range of 1-10 mcg/kg in order to maintain platelet counts between 50 and 200 x 109/L, 77 subjects received SOC treatment according to standard institutional practice or therapeutic guidelines.

The overall subject incidence rate of splenectomy was 8.9% (14 of 157 subjects) in the romiplostim group compared with 36.4% (28 of 77 subjects) in the SOC group, with an odds ratio (romiplostim vs SOC) of 0.17 (95% CI: 0.08, 0.35).

The overall subject incidence of treatment failure was 11.5% (18 of 157 subjects) in the romiplostim group compared with 29.9% (23 of 77 subjects) in the SOC group, with an odds ratio (romiplostim vs SOC) of 0.31 (95% CI: 0.15, 0.61).

Of the 157 subjects randomised to the romiplostim group, three subjects did not receive romiplostim. Among the 154 subjects who received romiplostim, the total median exposure to romiplostim was 52.0 weeks and ranged from 2 to 53 weeks. The most frequently used weekly dose was between 3-5 mcg/kg (25th-75th percentile respectively; median 3 mcg/kg).

Of the 77 subjects randomised to the SOC group, two subjects did not receive any SOC. Among the 75 subjects who received at least one dose of SOC, the total median exposure to SOC was 51 weeks and ranged from 0.4 to 52 weeks.

Reduction in permitted concurrent ITP medical therapies

In both placebo-controlled, double-blind studies, patients already receiving ITP medical therapies at a constant dosing schedule were allowed to continue receiving these medical treatments throughout the study (corticosteroids, danazol and/or azathioprine). Twenty-one non-splenectomised and 18 splenectomised patients received on-study ITP medical treatments (primarily corticosteroids) at the start of study. All (100%) splenectomised patients who were receiving romiplostim were able to reduce the dose by more than 25% or discontinue the concurrent ITP medical therapies by the end of the treatment period compared to 17% of placebo treated patients. Seventy-three percent of non-splenectomised patients receiving romiplostim were able to reduce the dose by more than 25% or discontinue concurrent ITP medical therapies by the end of the study compared to 50% of placebo treated patients (see section 4.5).

Bleeding events

Across the entire ITP clinical programme an inverse relationship between bleeding events and platelet counts was observed. All clinically significant (≥ grade 3) bleeding events occurred at platelet counts < 30 x 109/L. All bleeding events ≥ grade 2 occurred at platelet counts < 50 x 109/L. No statistically significant differences in the overall incidence of bleeding events were observed between Nplate and placebo treated patients.

In the two placebo-controlled studies, 9 patients reported a bleeding event that was considered serious (5 [6.0%] romiplostim, 4 [9.8%] placebo; Odds Ratio [romiplostim/placebo] = 0.59; 95% CI = (0.15, 2.31)). Bleeding events that were grade 2 or higher were reported by 15% of patients treated with romiplostim and 34% of patients treated with placebo (Odds Ratio; [romiplostim/placebo] = 0.35; 95% CI = (0.14, 0.85)).

Paediatric population

The European Medicines Agency has deferred the obligation to submit the results of studies with Nplate in one or more subsets of the paediatric population in the treatment of immune thrombocytopenia (idiopathic thrombocytopenic purpura) (see section 4.2 for information on paediatric use).

5.2 Pharmacokinetic properties

The pharmacokinetics of romiplostim involved target-mediated disposition, which is presumably mediated by TPO receptors on platelets and other cells of the thrombopoietic lineage such as megakaryocytes.

Absorption

After subcutaneous administration of 3 to 15 mcg/kg romiplostim, maximum romiplostim serum levels in ITP patients were obtained after 7-50 hours (median 14 hours). The serum concentrations varied among patients and did not correlate with the dose administered. Romiplostim serum levels appear inversely related to platelet counts.

Distribution

The volume of distribution of romiplostim following intravenous administration of romiplostim decreased nonlinearly from 122, 78.8, to 48.2 mL/kg for intravenous doses of 0.3, 1.0 and 10 mcg/kg, respectively in healthy subjects. This non-linear decrease in volume of distribution is in line with the (megakaryocyte and platelet) target-mediated binding of romiplostim, which may be saturated at the higher doses applied.

Elimination

Elimination half-life of romiplostim in ITP patients ranged from 1 to 34 days (median, 3.5 days).

The elimination of serum romiplostim is in part dependent on the TPO receptor on platelets. As a result for a given dose, patients with high platelet counts are associated with low serum concentrations and vice versa. In another ITP clinical trial, no accumulation in serum concentrations was observed after 6 weekly doses of romiplostim (3 mcg/kg).

Special populations

Pharmacokinetics of romiplostim in patients with renal and hepatic impairment has not been investigated. Romiplostim pharmacokinetics appear not affected by age, weight and gender to a clinically significant extent.

5.3 Preclinical safety data

Multiple dose romiplostim toxicology studies were conducted in rats for 4 weeks and in monkeys for up to 6 months. In general, effects observed during these studies were related to the thrombopoietic activity of romiplostim and were similar regardless of study duration. Injection site reactions were also related to romiplostim administration. Myelofibrosis has been observed in the bone marrow of rats at all tested dose levels. In these studies, myelofibrosis was not observed in animals after a 4-week post-treatment recovery period, indicating reversibility.

In 1-month rat and monkey toxicology studies, a mild decrease in red blood cell count, haematocrit and haemoglobin was observed. There was also a stimulatory effect on leukocyte production, as peripheral blood counts for neutrophils, lymphocytes, monocytes, and eosinophils were mildly increased. In the longer duration chronic monkey study, there was no effect on the erythroid and leukocytic lineages when romiplostim was administered for 6 months where the administration of romiplostim was decreased from thrice weekly to once weekly. Additionally, in the phase 3 pivotal studies, romiplostim did not affect the red blood cell and white blood cells lineages relative to placebo treated subjects.

Due to the formation of neutralising antibodies pharmacodynamic effects of romiplostim in rats were often decreasing at prolonged duration of administration. Toxicokinetic studies showed no interaction of the antibodies with the measured concentrations. Although high doses were tested in the animal studies, due to differences between the laboratory species and humans with regard to the sensitivity for the pharmacodynamic effect of romiplostim and the effect of neutralising antibodies, safety margins cannot be reliably estimated.

Carcinogenesis

The carcinogenic potential of romiplostim has not been evaluated. Therefore, the risk of potential carcinogenicity of romiplostim in humans remains unknown.

Reproductive toxicology

In all developmental studies neutralising antibodies were formed, which may have inhibited romiplostim effects. In embryo-foetal development studies in mice and rats, reductions in maternal body weight were found only in mice. In mice there was evidence of increased post-implantation loss. In a prenatal and postnatal development study in rats an increase of the duration of gestation and a slight increase in the incidence of peri-natal pup mortality was found. Romiplostim is known to cross the placental barrier in rats and may be transmitted from the mother to the developing foetus and stimulate foetal platelet production. Romiplostim had no observed effect on the fertility of rats.

6. Pharmaceutical particulars
6.1 List of excipients

Mannitol (E421)

Sucrose

L-histidine

Hydrochloric acid (for pH adjustment)

Polysorbate 20

Solvent:

Water for injections

6.2 Incompatibilities

This medicinal product must not be mixed with other medicinal products, except those mentioned in section 6.6.

6.3 Shelf life

3 years.

After reconstitution: Chemical and physical in-use stability has been demonstrated for 24 hours at 25°C and for 24 hours at 2°C – 8°C, when protected from light and kept in the original vial.

From a microbiological point of view, the medicinal product should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 25°C or 24 hours in a refrigerator (2°C – 8°C), protected from light.

6.4 Special precautions for storage

Store in a refrigerator (2°C – 8°C).

Do not freeze.

Store in the original carton in order to protect from light.

May be removed from the refrigerator for a period of 30 days at room temperature (up to 25°C) when stored in the original carton.

For storage conditions after reconstitution of the medicinal product, see section 6.3.

6.5 Nature and contents of container

Powder:

5 mL single-dose vial (type 1 clear glass) with a stopper (chlorobutyl rubber), seal (aluminium) and a flip-off cap (polypropylene).

Solvent:

Nplate 250 micrograms powder and solvent for solution for injection: Pre-filled syringe (type 1 clear glass with bromobutyl rubber plunger) containing 0.72 mL of water for injections for reconstitution.

Nplate 500 micrograms powder and solvent for solution for injection: Pre-filled syringe (type 1 clear glass with bromobutyl rubber plunger) containing 1.2 mL of water for injections for reconstitution.

Pack size:

Nplate 250 micrograms powder and solvent for solution for injection:

Nplate is supplied as a 1 pack or multipack comprising 4 packs. Each pack contains:

1 vial of 250 micrograms romiplostim.

1 pre-filled syringe containing 0.72 mL of water for injections for reconstitution.

1 plunger rod for the pre-filled syringe.

1 sterile vial adapter.

1 sterile 1 mL Luer lock syringe.

1 sterile safety needle.

4 alcohol swabs.

Nplate 500 micrograms powder and solvent for solution for injection:

Nplate is supplied as a 1 pack or multipack comprising 4 packs. Each pack contains:

1 vial of 500 micrograms romiplostim.

1 pre-filled syringe containing 1.2 mL of water for injections for reconstitution.

1 plunger rod for the pre-filled syringe.

1 sterile vial adapter.

1 sterile 1 mL Luer lock syringe.

1 sterile safety needle.

4 alcohol swabs.

Not all pack sizes may be marketed.

6.6 Special precautions for disposal and other handling

Nplate is a sterile but unpreserved medicinal product and is intended for single use only. Nplate should be reconstituted in accordance with good aseptic practice.

Nplate 250 micrograms powder and solvent for solution for injection

Nplate 250 micrograms powder for solution for injection should be reconstituted with 0.72 mL sterile water for injections, yielding a deliverable volume of 0.5 mL. An additional overfill is included in each vial to ensure that 250 mcg of romiplostim can be delivered (see vial content table below).

Nplate 500 micrograms powder and solvent for solution for injection

Nplate 500 micrograms powder for solution for injection should be reconstituted with 1.2 mL sterile water for injections, yielding a deliverable volume of 1 mL. An additional overfill is included in each vial to ensure that 500 mcg of romiplostim can be delivered (see vial content table below).

Vial Content:

Nplate single- use vial

Total vial content of romiplostim

Volume of sterile water for injection

Deliverable product and volume

Final concentration

250 mcg

375 mcg

+

0.72 mL

=

250 mcg in 0.50 mL

500 mcg/mL

500 mcg

625 mcg

+

1.20 mL

=

500 mcg in 1.00 mL

500 mcg/mL

From a microbiological point of view, the product should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user and would normally not be longer than 24 hours at 25°C or 24 hours in a refrigerator (2°C – 8°C), protected from light.

1. Remove the plastic cap from Nplate powder vial and clean rubber stopper using the provided alcohol swab.

2. Attach vial adapter to Nplate vial by peeling off paper backing from vial adapter, keeping the vial adapter in its packaging. Keeping the vial on the bench, push the vial adapter down onto the centre of the vial until it is firmly in place.

Note: To prevent contamination of the product, do not touch the vial adapter spike or Luer lock.

3. Remove and discard vial adapter packaging.

4. Attach plunger rod to the pre-filled syringe of water for injections by twisting the plunger rod clockwise onto the syringe plunger, until you feel a slight resistance.

5. Holding the pre-filled syringe of water for injections with one hand, bend the tip of the white plastic cover downward with your other hand. This will break the seal of the white plastic cover. Once the seal is broken, pull cover off to separate the grey rubber cap from the clear plastic tip on the syringe.

6. Keeping the vial on the bench, attach the pre-filled syringe of water for injections to vial adapter: hold the outer edge of the vial adapter with one hand and twist the syringe tip clockwise onto the adapter with the other hand until you feel a slight resistance.

7. Very slowly and gently expel all water into powder vial. Water should flow slowly onto powder. GENTLY swirl the vial until all of the powder has dissolved and the liquid in the vial is clear and colourless.

Do not shake the vial

Note: From a microbiological point of view, the product must be used immediately after reconstitution. If reconstituted product is not used immediately, the syringe should not be removed from the vial adapter to maintain microbiological integrity.

Note: This may take up to 2 minutes for the powder to completely dissolve.

Before continuing:

Do visually inspect the reconstituted solution for particulate matter and/or discolouration. The reconstituted solution should be clear and colourless and should not be administered if particulate matter and/or discolouration are observed.

Do make sure solution is fully dissolved before removing syringe.

8. Remove the empty pre-filled syringe from the vial adapter.

9. Remove 1 mL administration syringe from package. Attach the 1 mL syringe to vial adapter of reconstituted solution by twisting the syringe tip onto the vial adapter until you feel a slight resistance.

10. Turn assembled syringe-vial unit upside down, so the vial of reconstituted product is above the syringe. Withdraw all of the medicinal product solution into the administration syringe.

Do ensure that the plunger remains in the syringe.

11. Ensure the correct amount of solution for the patient dose is in the administration syringe by injecting any excess solution back into the vial.

Note: Remove all air bubbles from syringe to ensure precise solution amount is in syringe.

12. Twist off administration syringe from vial adapter.

Attach safety needle to the filled administration syringe by twisting needle clockwise into syringe Luer lock tip.

13. Prepare injection site with a new alcohol swab. Pull back on the pink safety cover toward the syringe and away from the needle.

Remove clear needle shield from prepared needle by holding syringe in one hand and carefully pulling shield straight off with the other hand.

14. Administer subcutaneous injection following local protocols and good aseptic technique.

15. After injecting, activate the pink safety cover by pushing the cover forward using the same hand until you hear and/or feel it click/lock.

16. Immediately discard syringe and needle into an approved Sharps Container.

For the storage condition after reconstitution of the product see section 6.3.

Any unused medicinal product or waste material should be disposed of in accordance with local requirements.

7. Marketing authorisation holder

Amgen Europe B.V.

Minervum 7061

4817 ZK Breda

The Netherlands

8. Marketing authorisation number(s)

EU/1/08/497/005

EU/1/08/497/006

EU/1/08/497/007

EU/1/08/497/008

9. Date of first authorisation/renewal of the authorisation

Date of first authorisation: 4 February 2009

Date of latest renewal: 20 December 2013

10. Date of revision of the text

January 2018

Detailed information on this medicinal product is available on the website of the European Medicines Agency http://www.ema.europa.eu

Company Contact Details
Amgen Ltd
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