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In uncontrolled trials with SYNRIBO, patients with chronic phase and accelerated phase CML experienced NCI CTC (version 3.0) Grade 3 or 4 thrombocytopenia (85%, 88%), neutropenia (81%, 71%), and anemia (62%, 80%), respectively. Fatalities related to myelosuppression occurred in 3% of patients in the safety population (N=163). Patients with neutropenia are at increased risk for infections, and should be monitored frequently and advised to contact a physician if they have symptoms of infection or fever. Monitor complete blood counts weekly during induction and initial maintenance cycles and every two weeks during later maintenance cycles, as clinically indicated. In clinical trials myelosuppression was generally reversible and usually managed by delaying next cycle and/or reducing days of treatment with SYNRIBO. [see DOSAGE AND ADMINISTRATION and ADVERSE REACTIONS]
SYNRIBO causes severe thrombocytopenia which increases the risk of hemorrhage. In clinical trials with CP and AP CML patients, a high incidence of Grade 3 and 4 thrombocytopenia (85% and 88%, respectively) was observed. Fatalities from cerebral hemorrhage occurred in 2% of patients treated with SYNRIBO in the safety population. Severe, non-fatal, gastrointestinal hemorrhages occurred in 2% of patients in the same population. Most bleeding events were associated with severe thrombocytopenia. Monitor platelet counts as part of the CBC monitoring as recommended. [see Myelosuppression] Avoid anticoagulants, aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs) when the platelet count is less than 50,000/μL as they may increase the risk of bleeding.
SYNRIBO can induce glucose intolerance. Grade 3 or 4 hyperglycemia was reported in 11% of patients in the safety population. Hyperosmolar non-ketotic hyperglycemia occurred in 1 patient treated with SYNRIBO in the safety population. Monitor blood glucose levels frequently, especially in patients with diabetes or risk factors for diabetes. Avoid SYNRIBO in patients with poorly controlled diabetes mellitus until good glycemic control has been established.
SYNRIBO can cause fetal harm when administered to a pregnant woman. Omacetaxine mepesuccinate caused embryo-fetal death in animals. Females of reproductive potential should avoid becoming pregnant while being treated with SYNRIBO. There are no adequate and well-controlled studies of SYNRIBO in pregnant women. If this drug is used during pregnancy, or if the patient becomes pregnant while receiving this drug, the patient should be apprised of the potential hazard to the fetus. [see Use in Specific Populations]
Carcinogenesis, Mutagenesis, Impairment Of Fertility
No carcinogenicity studies have been conducted with omacetaxine mepesuccinate. Omacetaxine mepesuccinate was genotoxic in an in vitro chromosomal aberration test system in Chinese hamster ovary (CHO) cells, but was not mutagenic when tested in an in vitro bacterial cell assay (Ames test), and it did not induce genetic damage using an in vivo mouse micronucleus assay. SYNRIBO may impair male fertility. Studies in mice demonstrated adverse effects on male reproductive organs. Bilateral degeneration of the seminiferous tubular epithelium in testes and hypospermia/aspermia in the epididymides were reported in the highest dose group (2.33 mg/kg/day reduced to 1.67 mg/kg/day; 7 to 5 mg/m²/day) following subcutaneous injection of omacetaxine mepesuccinate for six cycles over six months. The doses used in the mice were approximately two to three times the clinical dose (2.5 mg/m²/day) based on body surface area.
Use In Specific Populations
Pregnancy Category D
[see WARNINGS AND PRECAUTIONS]
Based on its mechanism of action and findings from animal studies, SYNRIBO can cause fetal harm when administered to pregnant women. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to a fetus. In an embryo-fetal development study, pregnant mice were administered omacetaxine mepesuccinate subcutaneously during the period of organogenesis at doses of 0.21 or 0.41 mg/kg/day. Drug-related adverse effects included embryonic death, an increase in unossified bones/reduced bone ossification and decreased fetal body weights. Fetal toxicity occurred at doses of 0.41 mg/kg (1.23 mg/m²) which is approximately half the recommended daily human dose on a body surface area basis.
It is not known whether omacetaxine mepesuccinate is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reaction in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
The safety and effectiveness of SYNRIBO in pediatric patients have not been established.
In the chronic and accelerated phase CML efficacy populations 23 (30%) and 16 (46%) patients were ≥ 65 years of age. For the age subgroups of < 65 years of age and ≥ 65 years of age, there were differences between the subgroups, with higher rates of major cytogenetic responses (MCyRs) in younger patients with CP CML compared with older patients (23% vs. 9%, respectively) and higher rates of major hematologic responses (MaHRs) in older patients with AP CML compared with younger patients (31% vs. 0%, respectively). Patients ≥ 65 years of age were more likely to experience toxicity, most notably hematologic toxicity.
No formal studies assessing the impact of renal impairment on the pharmacokinetics of omacetaxine mepesuccinate have been conducted.
No formal studies assessing the impact of hepatic impairment on the pharmacokinetics of omacetaxine mepesuccinate have been conducted.
Effect of Gender
Of the 76 patients included in the chronic phase CML population efficacy analysis, 47 (62%) of the patients were men and 29 (38%) were women. For patients with chronic phase CML, the MCyR rate in men was higher than in women (21% vs. 14%, respectively). There were differences noted in the safety profile of omacetaxine mepesuccinate in men and women with chronic phase CML although the small number of patients in each group prevents a definitive assessment. There were inadequate patient numbers in the accelerated phase subset to draw conclusions regarding a gender effect on efficacy.This monograph has been modified to include the generic and brand name in many instances.
Last reviewed on RxList: 2/20/2014
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