Amgen's Nplate(R) Rapidly Increased Platelet Counts in Adults With Primary ITP

ZUG, Switzerland, June 10, 2011 -

- Interim Results From Largest Study Of Adult ITP Patients To Date

Amgen today announced interim results from an international, single-arm
study ("209 study") evaluating the safety and efficacy of Nplate(R)
(romiplostim) in adults with primary immune thrombocytopenia (ITP) - a rare
blood disorder - demonstrated that Nplate induced a rapid platelet response
with a good safety profile in adult ITP patients with low platelet counts and
bleeding symptoms (Abstract #0223).

"This is the largest ever study in adult ITP with over 400 patients
enrolled. These interim data highlight again Nplate's ability to treat adult
patients successfully, including those with varying severity of the
condition," said Dr Ann Janssens, Department of Hematology, University
Hospitals Leuven, Belgium. "Nplate has consistently demonstrated that it can
significantly increase and maintain platelet counts in adult ITP patients,
highlighting its importance as a well-tolerated treatment option."

    Interim results from the first 235 patients show:

    - Nplate was able to induce a platelet response in a large majority of
      adult patients (90 percent) with primary ITP treated with Nplate for
      up to 201 weeks.

    - Median time to response was one week.

    - Over the course of the study, a doubling of the platelet count to
      greater than or equal to 50,000 platelets per microliter was achieved
      by 86 percent of patients who received Nplate.

    - A platelet count increase of greater than or equal to 20,000 platelets
      per microliter from baseline was achieved by 91 percent of patients who
      received Nplate.

Incidence and type of adverse events (AEs) in patients treated with
Nplate were consistent with those reported in previous studies. The most
common side effects were mild and included headache (28 percent of patients),
fatigue (23 percent) and arthralgia (19 percent). No neutralizing antibodies
to Nplate or thrombopoietin (TPO) or hematopoieitic malignancies or MDS
events were reported.

209 Study Design

This is an open-label, single-arm study of Nplate for the treatment of
adults with primary ITP. Nplate was administered once weekly, with dose
adjustments to maintain platelet counts of greater than or equal to 50,000
platelets per microliter. The primary study objective was incidence of AEs
and antibody formation. Secondary study objectives were to evaluate platelet
responses defined as either (1) doubling of baseline count and a platelet
count greater than or equal to 50,000 platelets per microliter or (2) a
platelet count increase of greater than or equal 20,000 platelets per
microliter from baseline.(1) As of June 2009, 235 patients had been treated
for a median of 18 weeks with a maximum duration of 201 weeks. Sixty percent
of patients had previously undergone splenectomy.

About Adult ITP

In patients with ITP, platelets - blood elements needed to prevent
bleeding - are destroyed by the patient's own immune system. Recent data also
suggest that low platelet counts in the blood may be caused by the inability
of the body's natural processes to produce platelets. Low platelet counts
leave adult ITP patients open to sudden serious bleeding events. The risk for
serious bleeding events increases when platelet counts drop to less than
30,000 platelets per microliter; normal counts range from 150,000 to 400,000
platelets per microliter. ITP has historically been considered a disease of
platelet destruction although recent data suggest that the body's natural
platelet production processes in ITP are unable to compensate for low levels
of platelets in the blood. Increasing the rate of platelet production may
address low platelet levels associated with ITP. Adult chronic ITP has an
incidence of 5.8-6.6 per 100,000 in the United States and an estimated 2.0
per 100,000 in the European Union.(2,3)

For more information about ITP please visit itpvillage.com

About Nplate

Nplate is the first platelet producer approved in most regions, including
the European Union (EU), Canada, Australia, Russia, Mexico, Switzerland and
the U.S. Nplate also has received orphan designation for chronic ITP in the
U.S. (2003), the EU (2005), Switzerland (2005), Japan (2006) and Mexico
(2010).

Nplate is the first FDA approved treatment specifically for adult chronic
ITP. It is also being investigated for potential use in children ages 12
months to 18 years old with persistent severe thrombocytopenia,
myelodysplastic syndromes (MDS) and chemotherapy-induced thrombocytopenia
(CIT).

In the EU, Nplate is indicated for the treatment of splenectomized adult
chronic ITP patients who are refractory to other treatments (e.g.
corticosteroids, immunoglobulins). Nplate may be considered as a second-line
treatment for adult non-splenectomized ITP patients for whom surgery is
contraindicated.

For more information about Nplate, please visit www.Nplate.com.

Important EU Nplate Safety Information

The most common side effects are headache, fatigue, arthralgia, myalgia,
injection site bruising, injection site pain, oedema peripheral, dizziness,
muscle spasms, nausea, contusion, diarrhoea, bone marrow disorder,
influenza-like illness, insomnia and pruritus.

Reoccurrence of thrombocytopenia and bleeding after cessation of
treatment and increased bone marrow reticulin have been associated with
Nplate treatment in the clinical trials. Thrombotic/thromboembolic
complications, progression of existing hematopoietic malignancies or MDS, and
effects on red and white blood cells are all potential risks associated with
Nplate treatment. As with all therapeutic proteins, patients may develop
antibodies to the therapeutic protein.

About Amgen

Amgen discovers, develops, manufactures and delivers innovative human
therapeutics. A biotechnology pioneer since 1980, Amgen was one of the first
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medicines, Amgen remains committed to advancing science to dramatically
improve people's lives. To learn more about our pioneering science and our
vital medicines, visit www.amgen.com.

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References

(1) Data on file. Interim Results from an International Multi-center,
Single-arm Study Evaluating the Safety and Efficacy of Romiplostim in Adults
with Primary Immune Thrombocytopenia (ITP). Abstract# 0223

(2) McMillan R. Therapy for Adults with Refractory Chronic Immune
Thrombocytopenic Purpura. Ann Intern Med 1997;126:307-314

(3) Fogarty PF et al. Curr Opin Hematol 2007;14:515-519.

Carrie Deverell, +41-41-3690-308 (E.U. media), or Christine Regan, +1-805-447-5476 (U.S. media), both of Amgen