2.1 Recommended Starting Dosage

2.2 Dose Titration Based Upon Platelet Response

Continue the starting dose for at least one week and then titrate to reduce and maintain the platelet count below 600,000/µL, and ideally between 150,000/µL and 400,000/µL. The dose increment should not exceed 0.5 mg/day in any one week. Dosage should not exceed 10 mg/day or 2.5 mg in a single dose. Most patients will experience an adequate response at a dose of 1.5 to 3.0 mg/day. Monitor platelet counts weekly during titration then monthly or as necessary.

2.3 Dose Modifications for Hepatic Impairment

In patients with moderate hepatic impairment (Child Pugh score 7-9) start AGRYLIN therapy at a dose of 0.5 mg/day and monitor frequently for cardiovascular events [see Warnings and Precautions (5.1), Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)]. Patients with moderate hepatic impairment who have tolerated AGRYLIN therapy for one week may have their dose increased. The dose increase increment should not exceed 0.5 mg/day in any one week. Avoid use of AGRYLIN in patients with severe hepatic impairment.

2.4 Clinical Monitoring

AGRYLIN therapy requires clinical monitoring, including complete blood counts, assessment of hepatic and renal function, and electrolytes.

To prevent the occurrence of thrombocytopenia, monitor platelet counts every two days during the first week of treatment and at least weekly thereafter until the maintenance dosage is reached. Typically, platelet counts begin to respond within 7 to 14 days at the proper dosage. In the clinical trials, the time to complete response, defined as platelet count ≤600,000/µL, ranged from 4 to 12 weeks. In the event of dosage interruption or treatment withdrawal, the rebound in platelet count is variable, but platelet counts typically will start to rise within 4 days and return to baseline levels in one to two weeks, possibly rebounding above baseline values. Monitor platelet counts frequently.

5.1 Cardiovascular Toxicity

Torsades de pointes and ventricular tachycardia have been reported with AGRYLIN. Obtain a pre-treatment cardiovascular examination including an ECG in all patients. During treatment with AGRYLIN monitor patients for cardiovascular effects and evaluate as necessary.

AGRYLIN increases the QTc interval of the electrocardiogram and increases the heart rate in healthy volunteers [see Clinical Pharmacology (12.2)].

Do not use AGRYLIN in patients with known risk factors for QT interval prolongation, such as congenital long QT syndrome, a known history of acquired QTc prolongation, medicinal products that can prolong QTc interval and hypokalemia [see Drug Interactions (7.1)].

Hepatic impairment increases anagrelide exposure and could increase the risk of QTc prolongation. Monitor patients with hepatic impairment for QTc prolongation and other cardiovascular adverse reactions. The potential risks and benefits of AGRYLIN therapy in a patient with mild and moderate hepatic impairment should be assessed before treatment is commenced. Reduce AGRYLIN dose in patients with moderate hepatic impairment. Avoid use of AGRYLIN in patients with severe hepatic impairment.

In patients with heart failure, bradyarrhythmias, or electrolyte abnormalities, consider periodic monitoring with electrocardiograms [see Clinical Pharmacology (12.2)].

AGRYLIN is a phosphodiesterase 3 (PDE3) inhibitor and may cause vasodilation, tachycardia, palpitations, and congestive heart failure. Other drugs that inhibit PDE3 have caused decreased survival when compared with placebo in patients with Class III-IV congestive heart failure [see Drug Interactions (7.2)].

In patients with cardiac disease, use AGRYLIN only when the benefits outweigh the risks.

5.2 Pulmonary Hypertension

Cases of pulmonary hypertension have been reported in patients treated with AGRYLIN. Evaluate patients for signs and symptoms of underlying cardiopulmonary disease prior to initiating and during AGRYLIN therapy [see Adverse Reactions (6.1)].

5.3 Bleeding Risk

Use of concomitant AGRYLIN and aspirin increased major hemorrhagic events in a postmarketing study. Assess the potential risks and benefits for concomitant use of AGRYLIN with aspirin, since bleeding risks may be increased. Monitor patients for bleeding, including those receiving concomitant therapy with other drugs known to cause bleeding (e.g., anticoagulants, PDE3 inhibitors, NSAIDs, antiplatelet agents, selective serotonin reuptake inhibitors) [see Drug Interactions (7.3), Clinical Pharmacology (12.3)].

5.4 Pulmonary Toxicity

Interstitial lung diseases (including allergic alveolitis, eosinophilic pneumonia and interstitial pneumonitis) have been reported to be associated with the use of AGRYLIN in post-marketing reports. Most cases presented with progressive dyspnea with lung infiltrations. The time of onset ranged from 1 week to several years after initiating AGRYLIN. If suspected, discontinue AGRYLIN and evaluate. Symptoms may improve after discontinuation [see Adverse Reactions (6)].

6.1 Clinical Trials Experience

Because clinical trials 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.

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-marketing use of AGRYLIN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Cardiac disorders: Prinzmetal angina, Torsades de pointes.

Respiratory, thoracic and mediastinal disorders: Interstitial lung diseases (including allergic alveolitis, eosinophilic pneumonia, and interstitial pneumonitis) [see Warnings and Precautions (5.4)].

Renal and urinary disorders: Tubulointerstitial nephritis.

Hepatobiliary disorders: Clinically significant hepatotoxicity (including symptomatic ALT and AST elevations and elevations greater than three times the ULN).

Nervous system disorders: Cerebral infarction

Other adverse reactions in pediatric patients reported in spontaneous reports and literature reviews include:

Blood and lymphatic system disorders: Anemia.

Skin and subcutaneous tissue disorders: Cutaneous photosensitivity.

Investigations: Elevated leukocyte count.

7.1 Drugs that Prolong QT

Avoid use of AGRYLIN in patients taking medications that may prolong QT interval (including, but not limited to, chloroquine, clarithromycin, haloperidol, methadone, moxifloxacin, amiodarone, disopyramide, procainamide, and pimozide) [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.2)].

7.2 PDE3 Inhibitors

AGRYLIN is a phosphodiesterase 3 (PDE3) inhibitor. Avoid use of drug products with similar properties such as inotropes and other PDE3 inhibitors (e.g., cilostazol, milrinone) [see Warnings and Precautions (5.1) and Clinical Pharmacology (12.2)].

7.3 Aspirin and Drugs that Increase Bleeding Risk

Co-administration of single-dose or repeat-dose AGRYLIN and aspirin showed greater ex vivo anti-platelet aggregation effects than administration of aspirin alone [see Clinical Pharmacology (12.3)]. Results from an observational study in patients with essential thrombocythemia suggest the rate of major hemorrhagic events (MHEs) in patients treated with AGRYLIN is higher than in those subjects treated with another cytoreductive treatment. The majority of the major hemorrhagic events occurred in patients who were also receiving concomitant anti-aggregatory treatment (primarily, aspirin). Therefore, the potential risks of the concomitant use of AGRYLIN with aspirin should be assessed, particularly in patients with a high-risk profile for hemorrhage, before treatment is initiated [see Warnings and Precautions (5.3)].

Monitor patients for bleeding, particularly those receiving concomitant therapy with other drugs known to cause bleeding (e.g., anticoagulants, PDE3 inhibitors, NSAIDs, antiplatelet agents, selective serotonin reuptake inhibitors).

7.4 CYP450 Interactions

8.1 Pregnancy

8.2 Lactation

8.3 Females and Males of Reproductive Potential

8.4 Pediatric Use

The safety and effectiveness of AGRYLIN have been established in pediatric patients 7 years of age and older. There are no data for pediatric patients less than 7 years of age. Use of AGRYLIN in these pediatric patients is supported by evidence from adequate and well controlled studies of AGRYLIN in adults with additional pharmacokinetic, pharmacodynamic, and safety data in 18 pediatric patients aged 7 through 16 years with thrombocythemia secondary to ET [see Dosage and Administration (2.1), Clinical Pharmacology (12.3), and Clinical Studies (14)].

There were no apparent trends or differences in the types of adverse events observed between the pediatric patients compared with those of the adult patients [see Adverse Reactions (6.1)].

8.5 Geriatric Use

Of the 942 subjects in clinical studies of AGRYLIN, 42.1% were 65 years and over, while 14.9% were 75 years and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in response between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

8.6 Hepatic Impairment

Hepatic metabolism is the major route of anagrelide clearance. Exposure to anagrelide is increased 8-fold in patients with moderate hepatic impairment [see Clinical Pharmacology (12.3)] and dose reduction is required [see Dosage and Administration (2.3)]. Use of AGRYLIN in patients with severe hepatic impairment has not been studied. Avoid use of AGRYLIN in patients with severe hepatic impairment. The potential risks and benefits of AGRYLIN therapy in a patient with mild and moderate hepatic impairment should be assessed before treatment is commenced. Assess hepatic function before and during AGRYLIN treatment [see Warnings and Precautions (5.1)].

12.1 Mechanism of Action

The precise mechanism by which anagrelide reduces blood platelet count is unknown. In cell culture studies, anagrelide suppressed expression of transcription factors including GATA-1 and FOG-1 required for megakaryocytopoiesis, ultimately leading to reduced platelet production.

12.2 Pharmacodynamics

In blood withdrawn from normal volunteers treated with anagrelide, a disruption was found in the postmitotic phase of megakaryocyte development and a reduction in megakaryocyte size and ploidy. At therapeutic doses, anagrelide does not produce significant changes in white cell counts or coagulation parameters, and may have a small, but clinically insignificant effect on red cell parameters. The active metabolite, 3-hydroxy anagrelide, has similar potency and efficacy to that of anagrelide in the platelet lowering effect; however, exposure (measured by plasma AUC) to 3-hydroxy anagrelide is approximately 2-fold higher compared to anagrelide. Anagrelide and 3-hydroxy anagrelide inhibit cyclic AMP phosphodiesterase 3 (PDE3) and 3-hydroxy anagrelide is approximately forty times more potent than anagrelide (IC50s = 0.9 and 36 nM, respectively). PDE3 inhibition does not alter platelet production. PDE3 inhibitors, as a class can inhibit platelet aggregation. However, significant inhibition of platelet aggregation is observed only at doses of anagrelide higher than those typically required to reduce platelet count. PDE3 inhibitors have cardiovascular (CV) effects including vasodilation, positive inotropy and chronotropy.

12.3 Pharmacokinetics

Dose proportionality has been found in the dose range 0.5 mg to 2.5 mg.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

In a two-year rat carcinogenicity study a higher incidence of uterine adenocarcinoma, relative to controls, was observed in females receiving 30 mg/kg/day (at least 174 times human AUC exposure after a 1 mg twice daily dose). Adrenal pheochromocytomas were increased relative to controls in males receiving 3 mg/kg/day and above, and in females receiving 10 mg/kg/day and above (at least 10 and 18 times respectively human AUC exposure after a 1 mg twice daily dose).

Anagrelide hydrochloride was not mutagenic in the bacterial mutagenesis (Ames) assay or the mouse lymphoma cell (L5178Y, TK+/-) forward mutation assay, and was not clastogenic in the in vitro chromosome aberration assay using human lymphocytes or the in vivo mouse micronucleus test.

Anagrelide hydrochloride at oral doses up to 240 mg/kg/day (233 times the recommended human dose of 10 mg/day based on body surface area) had no effect on fertility and reproductive function of male rats. However, in fertility studies in female rats, oral doses of 30 mg/kg/day (29 times the recommended maximum human dose based on body surface area) or higher resulted in increased pre- and post-implantation loss and a decrease in the number of live embryos.

13.2 Animal Toxicology and/or Pharmacology

In the 2-year rat study, a significant increase in non-neoplastic lesions was observed in anagrelide treated males and females in the adrenal (medullary hyperplasia), heart (myocardial hypertrophy and chamber distension), kidney (hydronephrosis, tubular dilation and urothelial hyperplasia), and bone (femur enostosis). Vascular effects were observed in tissues of the pancreas (arteritis/periarteritis, intimal proliferation, and medial hypertrophy), kidney (arteritis/periarteritis, intimal proliferation, and medial hypertrophy), sciatic nerve (vascular mineralization), and testes (tubular atrophy and vascular infarct) in anagrelide-treated males.

Clinical Studies in Adult Patients:

A total of 942 patients with myeloproliferative neoplasms including 551 patients with Essential Thrombocythemia (ET), 117 patients with Polycythemia Vera (PV), 178 patients with Chronic Myelogenous Leukemia (CML), and 96 patients with other myeloproliferative neoplasms (OMPN), were treated with AGRYLIN in three clinical trials. Patients with OMPN included 87 patients who had Myeloid Metaplasia with Myelofibrosis (MMM), and 9 patients who had unclassified myeloproliferative neoplasms.

Patients were enrolled in clinical trials if their platelet count was ≥900,000/µL on two occasions or ≥650,000/µL on two occasions with documentation of symptoms associated with thrombocythemia. The mean duration of AGRYLIN therapy for ET, PV, CML, and OMPN patients was 65, 67, 40, and 44 weeks, respectively; 23% of patients received treatment for 2 years. Patients were treated with AGRYLIN starting at doses of 0.5-2.0 mg every 6 hours. The dose was increased if the platelet count was still high, but to no more than 12 mg each day. Efficacy was defined as reduction of platelet count to or near physiologic levels (150,000-400,000/µL). The criteria for defining subjects as "responders" were reduction in platelets for at least 4 weeks to ≤600,000/µL, or by at least 50% from baseline value. Subjects treated for less than 4 weeks were not considered evaluable. The results are depicted graphically below:

AGRYLIN was effective in phlebotomized patients as well as in patients treated with other concomitant therapies including hydroxyurea, aspirin, interferon, radioactive phosphorus, and alkylating agents.

Clinical Study in Pediatric Patients:

An open-label safety and PK/PD study was conducted in 18 pediatric patients 7 through 16 years of age (8 children 7 through 11 years of age and 10 adolescents 12 through 16 years of age, mean age of 12 years; 8 males and 10 females) with thrombocythemia secondary to ET as compared to 17 adult patients (mean age of 66 years, 9 males and 8 females). Prior to entry on to the study, 17 of 18 pediatric patients and 12 of 17 adult patients had received AGRYLIN treatment for an average of 2 years. The median starting total daily dose, determined by retrospective chart review, for pediatric and adult patients with ET who had received AGRYLIN prior to study entry was 1 mg for each of the three age groups (7 through 11 and 12 through 16 years of age and adults). The starting dose for 6 AGRYLIN-naive patients at study entry was 0.5 mg once daily. At study completion, the median total daily maintenance doses were similar across age groups, median of 1.75 mg for children of 7 through 11 years of age, 2.25 mg in adolescents 12 through 16 years of age, and 1.5 mg for adults.

Store at 25°C (77°F) excursions permitted to 15°C to 30°C (59°F to 86°F), [See USP Controlled Room Temperature]. Store in a light resistant container.