DrugLib.com — Drug Information Portal

Rx drug information, pharmaceutical research, clinical trials, news, and more

Nplate (Romiplostim Subcutaneous) - Side Effects and Adverse Reactions



Clinical Studies Experience

Serious adverse reactions associated with Nplate in clinical studies were bone marrow reticulin deposition and worsening thrombocytopenia after Nplate discontinuation [ see Warnings and Precautions (5.1, 5.2) ].

The data described below reflect Nplate exposure to 271 patients with chronic ITP, aged 18 to 88, of whom 62% were female. Nplate was studied in two randomized, placebo-controlled, double-blind studies that were identical in design, with the exception that Study 1 evaluated nonsplenectomized patients with ITP and Study 2 evaluated splenectomized patients with ITP.  Data are also reported from an open-label, single-arm study in which patients received Nplate over an extended period of time. Overall, Nplate was administered to 114 patients for at least 52 weeks and 53 patients for at least 96 weeks.

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In the placebo-controlled studies, headache was the most commonly reported adverse drug reaction, occurring in 35% of patients receiving Nplate and 32% of patients receiving placebo. Headaches were usually of mild or moderate severity. Table 2 presents adverse drug reactions from Studies 1 and 2 with a ≥ 5% higher patient incidence in Nplate versus placebo. The majority of these adverse drug reactions were mild to moderate in severity.

Table 2. Adverse Drug Reactions Identified in Two Placebo-Controlled Studies
Preferred Term


(n = 84)


(n = 41)

Pain in extremity13%5%
Abdominal Pain11%0%
Shoulder Pain8%0%

Among 142 patients with chronic ITP who received Nplate in the single-arm extension study, the incidence rates of the adverse reactions occurred in a pattern similar to those reported in the placebo-controlled clinical studies.


As with all therapeutic proteins, patients may develop antibodies to the therapeutic protein. Patients were screened for immunogenicity to romiplostim using a BIAcore-based biosensor immunoassay. This assay is capable of detecting both high- and low-affinity binding antibodies that bind to romiplostim and cross-react with TPO. The samples from patients that tested positive for binding antibodies were further evaluated for neutralizing capacity using a cell-based bioassay.

In clinical studies, the incidence of preexisting antibodies to romiplostim was 8% (17/225) and the incidence of binding antibody development during Nplate treatment was 10% (23/225). The incidence of preexisting antibodies to endogenous TPO was 5% (12/225) and the incidence of binding antibody development to endogenous TPO during Nplate treatment was 5% (12/225). Of the patients with positive antibodies to romiplostim or to TPO, one (0.4%) patient had neutralizing activity to romiplostim and none had neutralizing activity to TPO. No correlation was observed between antibody activity and clinical effectiveness or safety.

Immunogenicity assay results are highly dependent on the sensitivity and specificity of the assay used in detection and may be influenced by several factors, including sample handling, concomitant medications, and underlying disease. For these reasons, comparison of incidence of antibodies to romiplostim with the incidence of antibodies to other products may be misleading.


Below is a sample of reports where side effects / adverse reactions may be related to Nplate. The information is not vetted and should not be considered as verified clinical evidence.

Possible Nplate side effects / adverse reactions in 88 year old female

Reported by a physician from France on 2011-10-03

Patient: 88 year old female

Reactions: Phlebitis

Adverse event resulted in: hospitalization

Suspect drug(s):

Possible Nplate side effects / adverse reactions in 56 year old female

Reported by a health professional (non-physician/pharmacist) from United States on 2011-10-03

Patient: 56 year old female

Reactions: Biopsy Bone Marrow Abnormal, Neuropathy Peripheral, Hypovitaminosis

Suspect drug(s):

Other drugs received by patient: Calcium + Vitamin D /01483701/; Reston /00000401/; Lexapro; Synthroid; Vicodin

Possible Nplate side effects / adverse reactions in 83 year old male

Reported by a physician from Netherlands on 2011-10-03

Patient: 83 year old male weighing 84.0 kg (184.8 pounds)

Reactions: Pulmonary Embolism

Adverse event resulted in: life threatening event, hospitalization

Suspect drug(s):

Other drugs received by patient: Cyklokapron

See index of all Nplate side effect reports >>

Drug label data at the top of this Page last updated: 2008-09-11

-- advertisement -- The American Red Cross
Home | About Us | Contact Us | Site usage policy | Privacy policy

All Rights reserved - Copyright DrugLib.com, 2006-2015