A Study Evaluating the Safety and Efficacy of Long-term Dosing of Romiplostim in Thrombocytopenic Pediatric Patients With Immune (Idiopathic) Thrombocytopenia Purpura

Inclusion Criteria:

- Subject or subject's legally acceptable representative has provided informed consent.

- Subject completed a romiplostim study for the treatment of thrombocytopenia in
pediatric subjects with ITP.

Exclusion Criteria:

- Subject has or previously had any bone marrow stem cell disorder (any abnormal bone
marrow findings other than those typical of ITP must be approved by Amgen before a
subject may be enrolled in the study).

- Subject has any new active malignancy diagnosed since enrollment in the previous
romiplostim ITP study.

- Subject received any alkylating agents within four weeks before the screening visit or
anticipated use during the time of the proposed study.

- Other investigational medications are excluded.

- Currently enrolled in another investigational device or drug study, or less than 30
days since ending another investigational device or drug study(s), or receiving other
investigational agent(s) (with the exception of romiplostim in a previous clinical
study).

- Female subject of child bearing potential (defined as having first menses) is not
willing to use highly effective contraception during treatment and for 4 weeks after
the end of treatment.

- Female subject is pregnant or breast feeding, or planning to become pregnant within 4
weeks after the end of treatment.

- Subject has known sensitivity to any of the products to be administered during dosing.

- Subject previously has entered this study (this will depend on the type of study).

- Subject will not be available for protocol required study visits, to the best of the
subject and investigator's knowledge.

- Subject has any kind of disorder that, in the opinion of the investigator, may
compromise the ability of the subject to give written informed consent and/or to
comply with all required study procedures.