Nplate is indicated for the treatment of thrombocytopenia in patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins or splenectomy.

Limitations of use

• Nplate is not indicated for the treatment of thrombocytopenia due to myelodysplastic syndrome (MDS) or any cause of thrombocytopenia other than chronic ITP [see WARNINGS AND PRECAUTIONS].
• Nplate should be used only in patients with ITP whose degree of thrombocytopenia and clinical condition increases the risk for bleeding [see WARNINGS AND PRECAUTIONS].
• Nplate should not be used in an attempt to normalize platelet counts [see WARNINGS AND PRECAUTIONS].

Recommended Dosage Regimen

Use the lowest dose of Nplate to achieve and maintain a platelet count ≥ 50 x 10⁹/L as necessary to reduce the risk for bleeding. Administer Nplate as a weekly subcutaneous injection with dose adjustments based upon the platelet count response.

The prescribed Nplate dose may consist of a very small volume (eg, 0.15 mL). Administer Nplate only with a syringe that contains 0.01 mL graduations.

Initial Dose

The initial dose for Nplate is 1 mcg/kg based on actual body weight.

Dose Adjustments

Use the actual body weight at initiation of therapy, then adjust the weekly dose of Nplate by increments of 1 mcg/kg until the patient achieves a platelet count ≥ 50 x 10⁹/L as necessary to reduce the risk for bleeding; do not exceed a maximum weekly dose of 10 mcg/kg. In clinical studies, most patients who responded to Nplate achieved and maintained platelet counts ≥ 50 x 10⁹/L with a median dose of 2 mcg/kg.

During Nplate therapy, assess CBCs, including platelet counts, weekly until a stable platelet count ( ≥ 50 x 10⁹/L for at least 4 weeks without dose adjustment) has been achieved. Obtain CBCs, including platelet counts, monthly thereafter.

Adjust the dose as follows

• If the platelet count is < 50 x 10⁹/L, increase the dose by 1 mcg/kg.
• If platelet count is > 200 x 10⁹/L for 2 consecutive weeks, reduce the dose by 1 mcg/kg.
• If platelet count is > 400 x 10⁹/L, do not dose. Continue to assess the platelet count weekly. After the platelet count has fallen to < 200 x 10⁹/L, resume Nplate at a dose reduced by 1 mcg/kg.

Discontinuation

Discontinue Nplate if the platelet count does not increase to a level sufficient to avoid clinically important bleeding after 4 weeks of Nplate therapy at the maximum weekly dose of 10 mcg/kg [see WARNINGS AND PRECAUTIONS]. Obtain CBCs, including platelet counts, weekly for at least 2 weeks following discontinuation of Nplate [see WARNINGS AND PRECAUTIONS].

Administration Precautions

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 [see WARNINGS AND PRECAUTIONS and OVERDOSAGE].

Preparation and Administration

Nplate is supplied in single-use vials as a sterile, preservative-free, white lyophilized powder that must be reconstituted as outlined in Table 1 and administered using a syringe with 0.01 mL graduations. Using aseptic technique, reconstitute Nplate with preservative-free Sterile Water for Injection, USP as described in Table 1. Do not use bacteriostatic water for injection.

Table 1: Reconstitution of Nplate Single-Use Vials

Gently swirl and invert the vial to reconstitute. Avoid excess or vigorous agitation: DO NOT SHAKE. Generally, dissolution of Nplate takes less than 2 minutes. The reconstituted Nplate solution should be clear and colorless. Visually inspect the reconstituted solution for particulate matter and/or discoloration. Do not administer Nplate if particulate matter and/or discoloration is observed.

Reconstituted Nplate can be kept at room temperature (25°C/77°F) or refrigerated at 2° to 8°C (36° to 46°F) for up to 24 hours prior to administration. Protect the reconstituted product from light.

To determine the injection volume to be administered, first identify the patient's total dose in micrograms (mcg) using the dosing information in Section 2.1. For example, a 75 kg patient initiating therapy at 1 mcg/kg will begin with a dose of 75 mcg. Next, calculate the volume of Nplate solution that is given to the patient by dividing the microgram dose by the concentration of the reconstituted Nplate solution (500 mcg/mL). For this patient example, the 75 mcg dose is divided by 500 mcg/mL, resulting in an injection volume of 0.15 mL.

As the injection volume may be very small, use a syringe with graduations to 0.01 mL.

Discard any unused portion. Do not pool unused portions from the vials. Do not administer more than one dose from a vial.

Use of Nplate With Concomitant Medical ITP Therapies

Nplate may be used with other medical ITP therapies, such as corticosteroids, danazol, azathioprine, intravenous immunoglobulin (IVIG), and anti-D immunoglobulin. If the patient's platelet count is ≥ 50 x 10⁹/L, medical ITP therapies may be reduced or discontinued [see Clinical Studies].

Dosage Forms And Strengths

Single-use vials contain 250 or 500 mcg of deliverable romiplostim as a sterile, lyophilized, solid white powder.

Storage And Handling

Nplate is supplied in single-use vials containing 250 mcg (NDC 55513-221-01) and 500 mcg (NDC 55513-222-01) deliverable romiplostim.

Store Nplate vials in their carton to protect from light until time of use. Keep Nplate vials refrigerated at 2° to 8°C (36° to 46°F). Do not freeze.

Nplate® (romiplostim), Manufactured by: Amgen Inc., One Amgen Center Drive Thousand Oaks, California 91320-1799. Revised 11/2012

Last reviewed on RxList: 12/5/2012
This monograph has been modified to include the generic and brand name in many instances.