欧盟已经批准了第一个用于骨髓纤维化治疗的药物-Ruxolitinib。Ruxolitinib，一个口服的JAK1和JAK2抑制剂，被批准用于治疗疾病相关的脾肿大或者成人原发性骨髓纤维化 (慢性特发性骨髓纤维化)，红细胞增多后髓样化增生或者血小板增多后骨髓纤维化病症
Ruxolitinib将在欧盟销售，商品名为Jakavi。诺华已经有一个Jakfi在美国市场销售了，代理商为因赛特，是2011年11月在美国获批的，曾经是第一个骨髓纤维化治疗药物。
这次诺华能获批，是基于一对关键的3期临床试验，被称为COMFORT（骨纤维化控制试验中口服JAK抑制剂治疗)-1和COMFORT-2骨髓纤维化主要表现为骨髓衰竭，脾肿大，虚弱(比如极度疲劳，盗汗和顽固性瘙痒)，生活质量差和体重减少。也会缩短患者的生存时间。
两个COMFORT试验研究显示了ruxolitinib能改善脾肿大和其它的症状。COMFORT-1 的结果显示用ruxolitinib治疗后24周，41%的患者的脾体积至少减小了35%，相比之下，安慰剂组(p<0.01)达到这个效果的只有0.7%的患者。COMFORT-2研究结果发现，ruxolitinib治疗组在给药48周后，28%的患者脾脏体积减小程度和最佳可用疗法组中0%的患者相似（p<0.001）。其它的一些症状也得到了改善，包括患者行动能力减弱，疲劳，疼痛和胃口不好。
COMFORT-2的主要研究者，来自于英国伦敦盖伊和圣托马斯国民保健信托基金会的Claire Harrison, MD在欧盟的报批材料中陈述，“ruxolitinib具有切实改善病人的身体状况的潜能，这给迫切需要治疗的患者提供了一个新的治疗方案。” 诺华公司称，这个药物最常见的不良反应(发生率>10%)是泌尿道感染，贫血，血小板减少，中性粒细胞减少，高胆固醇血症，头晕，头疼，肝药酶升高，擦伤，出血和血压升高，推荐使用完整的血液检测。

Jakavi 5mg, 10mg, 15mg and 20mg Tablets
1. Name of the medicinal product
Jakavi® 5 mg tablets
Jakavi® 10 mg tablets
Jakavi® 15 mg tablets
Jakavi® 20 mg tablets
2. Qualitative and quantitative composition
Jakavi 5 mg tablets: Each tablet contains 5 mg ruxolitinib (as phosphate).
Jakavi 10 mg tablets: Each tablet contains 10 mg ruxolitinib (as phosphate).
Jakavi 15 mg tablets: Each tablet contains 15 mg ruxolitinib (as phosphate).
Jakavi 20 mg tablets : Each tablet contains 20 mg ruxolitinib (as phosphate).
Excipient with known effect:
Jakavi 5 mg tablets: Each tablet contains 71.45 mg lactose monohydrate.
Jakavi 10 mg tablets: Each tablet contains 142.90 mg lactose monohydrate.
Jakavi 15 mg tablets: Each tablet contains 214.35 mg lactose monohydrate.
Jakavi 20 mg tablets : Each tablet contains 285.80 mg lactose monohydrate.
For the full list of excipients, see section 6.1.
3. Pharmaceutical form
Tablet.
Jakavi 5mg tablets: Round curved white to almost white tablets of approximately 7.5 mm in diameter with “NVR” debossed on one side and “L5” debossed on the other side.
Jakavi 10mg tablets: Round curved white to almost white tablets of approximately 9.3 mm in diameter with "NVR" debossed on one side and "L10" debossed on the other side.
Jakavi 15mg tablets : Ovaloid curved white to almost white tablets of approximately 15.0 x 7.0 mm with “NVR” debossed on one side and “L15” debossed on the other side.
Jakavi 20mg tablets : Elongated curved white to almost white tablets of approximately 16.5 x 7.4 mm with “NVR” debossed one one side and “L20” debossed on the other side.
4. Clinical particulars
4.1 Therapeutic indications
Jakavi is indicated for the treatment of disease-related splenomegaly or symptoms in adult patients with primary myelofibrosis (also known as chronic idiopathic myelofibrosis), post polycythaemia vera myelofibrosis or post essential thrombocythaemia myelofibrosis.
4.2 Posology and method of administration
Jakavi treatment should only be initiated by a physician experienced in the administration of anti-cancer agents.
A complete blood cell count, including a white blood cell count differential, must be performed before initiating therapy with Jakavi.
Complete blood count, including a white blood cell count differential, should be monitored every 2-4 weeks until Jakavi doses are stabilised, and then as clinically indicated (see section 4.4).
Posology
Starting dose
The recommended starting dose of Jakavi is 15 mg twice daily for patients with a platelet count between 100,000/mm3 and 200,000/mm3 and 20 mg twice daily for patients with a platelet count of >200,000/mm3. There is limited information to recommend a starting dose for patients with platelet counts between 50,000/mm3 and <100,000/mm3. The maximum recommended starting dose in these patients is 5 mg twice daily and the patients should be titrated cautiously.
Dose modifications
Doses may be titrated based on safety and efficacy. Treatment should be discontinued for platelet counts less than 50,000/mm3 or absolute neutrophil counts less than 500/mm3. After recovery of platelet and neutrophil counts above these levels, dosing may be re-started at 5 mg twice daily and gradually increased based on careful monitoring of complete blood cell count, including a white blood cell count differential.
Dose reductions should be considered if the platelet count decreases below 100,000/mm3, with the goal of avoiding dose interruptions for thrombocytopenia.
If efficacy is considered insufficient and platelet and neutrophil counts are adequate, doses may be increased by a maximum of 5 mg twice daily.
The starting dose should not be increased within the first four weeks of treatment and thereafter no more frequently than at 2-week intervals.
The maximum dose of Jakavi is 25 mg twice daily.
Dose adjustment with concomitant strong CYP3A4 inhibitors or fluconazole
When Jakavi is administered with strong CYP3A4 inhibitors or dual inhibitors of CYP2C9 and CYP3A4 enzymes (e.g. fluconazole) the unit dose of Jakavi should be reduced by approximately 50%, to be administered twice daily (see section 4.5).
More frequent monitoring (e.g. twice a week) of haematology parameters and of clinical signs and symptoms of Jakavi-related adverse drug reactions is recommended while on strong CYP3A4 inhibitors or dual inhibitors of CYP2C9 and CYP3A4 enzymes.
Special populations
Renal impairment
No specific dose adjustment is needed in patients with mild or moderate renal impairment.
In patients with severe renal impairment (creatinine clearance less than 30 ml/min) the recommended starting dose based on platelet count should be reduced by approximately 50% to be administered twice daily. Patients should be carefully monitored with regard to safety and efficacy during Jakavi treatment.
There are limited data to determine the best dosing options for patients with end stage renal disease (ESRD) on haemodialysis. Pharmacokinetic/pharmacodynamic simulations based on available data in this population suggest that the starting dose for patients with ESRD on haemodialysis is a single dose of 15-20 mg or two doses of 10 mg given 12 hours apart, to be administered post-dialysis and only on the day of haemodialysis. A single dose of 15 mg is recommended for patients with platelet count between 100,000/mm3 and 200,000/mm3. A single dose of 20 mg or two doses of 10 mg given 12 hours apart is recommended for patients with platelet count of >200,000/mm3. Subsequent doses (single administration or two doses of 10 mg given 12 hours apart) should be administered only on haemodialysis days following each dialysis session. These dose recommendations are based on simulations and any dose modification in ESRD should be followed by careful monitoring of safety and efficacy in individual patients. No data is available for dosing patients who are undergoing peritoneal dialysis or continuous venovenous haemofiltration (see section 5.2).
Hepatic impairment
In patients with any hepatic impairment the recommended starting dose based on platelet count should be reduced by approximately 50% to be administered twice daily. Subsequent doses should be adjusted based on careful monitoring of safety and efficacy. Patients diagnosed with hepatic impairment while receiving Jakavi should have complete blood counts, including a white blood cell count differential, monitored at least every one to two weeks for the first 6 weeks after initiation of therapy with Jakavi and as clinically indicated thereafter once their liver function and blood counts have been stabilised. Jakavi dose can be titrated to reduce the risk of cytopenia.
Older people (≥65 years)
No additional dose adjustments are recommended for older people.
Paediatric population
The safety and efficacy of Jakavi in children aged up to 18 years have not been established. No data are available (see section 5.1).
Treatment discontinuation
Treatment may be continued as long as the benefit-risk remains positive. However the treatment should be discontinued after 6 months if there has been no reduction in spleen size or improvement in symptoms since initiation of therapy.
It is recommended that, for patients who have demonstrated some degree of clinical improvement, ruxolitinib therapy be discontinued if they sustain an increase in their spleen length of 40% compared with baseline size (roughly equivalent to a 25% increase in spleen volume) and no longer have tangible improvement in disease-related symptoms.
Method of administration
Jakavi is to be taken orally, with or without food.
If a dose is missed, the patient should not take an additional dose, but should take the next usual prescribed dose.
4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
Pregnancy and lactation.
4.4 Special warnings and precautions for use
Myelosuppression
Treatment with Jakavi can cause haematological adverse drug reactions, including thrombocytopenia, anaemia and neutropenia. A complete blood count, including a white blood cell count differential, must be performed before initiating therapy with Jakavi. Treatment should be discontinued in patients with platelet count less than 50,000/mm3 or absoute neutrophil count less than 500/mm3 (see section 4.2).
It has been observed that patients with low platelet counts (<200,000/mm3) at the start of therapy are more likely to develop thrombocytopenia during treatment.
Thrombocytopenia is generally reversible and is usually managed by reducing the dose or temporarily withholding Jakavi (see sections 4.2 and 4.8). However, platelet transfusions may be required as clinically indicated.
Patients developing anaemia may require blood transfusions. Dose modifications for patients developing anaemia may also be considered.
Patients with a haemoglobin level below 10.0 g/dl at the beginning of the treatment have a higher risk of developing a haemoglobin level below 8.0 g/dl during treatment compared to patients with a higher baseline haemoglobin level (79.3% versus 30.1%). More frequent monitoring of haematology parameters and of clinical signs and symptoms of Jakavi-related adverse drug reactions is recommended for patients with baseline haemoglobin below 10.0 g/dl.
Neutropenia (absolute neutrophil count <500) was generally reversible and was managed by temporarily withholding Jakavi (see sections 4.2 and 4.8).
Complete blood counts should be monitored as clinically indicated and dose adjusted as required (see sections 4.2 and 4.8).
Infections
Patients should be assessed for the risk of developing serious bacterial, mycobacterial, fungal and viral infections. Tuberculosis has been reported in patients receiving Jakavi for myelofibrosis. Before starting treatment, patients should be evaluated for active and inactive ("latent") tuberculosis, as per local recommendations. This can include medical history, possible previous contact with tuberculosis, and/or appropriate screening such as lung x-ray, tuberculin test and/or interferon-gamma release assay, as applicable. Prescribers are reminded of the risk of false negative tuberculin skin test results, especially in patients who are severely ill or immunocompromised. Jakavi therapy should not be started until active serious infections have resolved. Physicians should carefully observe patients receiving Jakavi for signs and symptoms of infections and initiate appropriate treatment promptly (see section 4.8).
Herpes zoster
Physicians should educate patients about early signs and symptoms of herpes zoster, advising that treatment should be sought as early as possible.
Progressive multifocal leukoencephalopathy
Progressive multifocal leukoencephalopathy (PML) has been reported with Jakavi treatment for myelofibrosis. Physicians should be particularly alert to symptoms suggestive of PML that patients may not notice (e.g., cognitive, neurological or psychiatric symptoms or signs). Patients should be monitored for any of these new or worsening symptoms or signs, and if such symptoms/signs occur, referral to a neurologist and appropriate diagnostic measures for PML should be considered. If PML is suspected, further dosing must be suspended until PML has been excluded.
Special populations
Renal impairment
The starting dose of Jakavi should be reduced in patients with severe renal impairment. For patients with end-stage renal disease on haemodialysis the starting dose should be based on platelet counts (see section 4.2). Subsequent doses (single administration or two doses of 10 mg given 12 hours apart) should be administered only on haemodialysis days following each dialysis session. Additional dose modifications should be made with careful monitoring of safety and efficacy (see sections 4.2 and 5.2).
Hepatic impairment
The starting dose of Jakavi should be reduced by approximately 50% in patients with hepatic impairment. Further dose modifications should be based on the safety and efficacy of the medicinal product (see sections 4.2 and 5.2).
Interactions
If Jakavi is to be co-administered with strong CYP3A4 inhibitors or dual inhibitors of CYP3A4 and CYP2C9 enzymes (e.g. fluconazole), the unit dose of Jakavi should be reduced by approximately 50%, to be administered twice daily (for monitoring frequency see sections 4.2 and 4.5).
The concomitant use of cytoreductive therapies or haematopoietic growth factors with Jakavi has not been studied. The safety and efficacy of these co-administrations are not known (see section 4.5).
Withdrawal effects
Following interruption or discontinuation of Jakavi, symptoms of myelofibrosis may return over a period of approximately one week. There have been cases of patients discontinuing Jakavi who sustained more severe events, particularly in the presence of acute intercurrent illness. It has not been established whether abrupt discontinuation of Jakavi contributed to these events. Unless abrupt discontinuation is required, gradual tapering of the dose of Jakavi may be considered, although the utility of the tapering is unproven.
Excipients
Jakavi contains lactose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicinal product.
4.5 Interaction with other medicinal products and other forms of interaction
Interaction studies have only been performed in adults.
Ruxolitinib is eliminated through metabolism catalysed by CYP3A4 and CYP2C9. Thus, medicinal products inhibiting these enzymes can give rise to increased ruxolitinib exposure.
Interactions resulting in dose reduction of ruxolitinib
CYP3A4 inhibitors
Strong CYP3A4 inhibitors (such as, but not limited to, boceprevir, clarithromycin, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, ritonavir, mibefradil, nefazodone, nelfinavir, posaconazole, saquinavir, telaprevir, telithromycin, voriconazole)
In healthy subjects co-administration of Jakavi (10 mg single dose) with a strong CYP3A4 inhibitor, ketoconazole, resulted in ruxolitinib Cmax and AUC that were higher by 33% and 91%, respectively, than with ruxolitinib alone. The half-life was prolonged from 3.7 to 6.0 hours with concurrent ketoconazole administration.
When administering Jakavi with strong CYP3A4 inhibitors the unit dose of Jakavi should be reduced by approximately 50%, to be administered twice daily. Patients should be closely monitored (e.g. twice weekly) for cytopenias and dose titrated based on safety and efficacy (see section 4.2).
Dual CYP2C9 and CYP3A4 inhibitors
On the basis of in silico modelling 50% dose reduction should be considered when using medicinal products which are dual inhibitors of CYP2C9 and CYP3A4 enzymes (e.g. fluconazole).
Enzyme inducers
CYP3A4 inducers (such as, but not limited to, avasimibe, carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin (rifampicin), St.John's wort (Hypericum perforatum))
Patients should be closely monitored and the dose titrated based on safety and efficacy (see section 4.2).
In healthy subjects given ruxolitinib (50 mg single dose) following the potent CYP3A4 inducer rifampicin (600 mg daily dose for 10 days), ruxolitinib AUC was 70% lower than after administration of Jakavi alone. The exposure of ruxolitinib active metabolites was unchanged. Overall, the ruxolitinib pharmacodynamic activity was similar, suggesting the CYP3A4 induction resulted in minimal effect on the pharmacodynamics. However, this could be related to the high ruxolitinib dose resulting in pharmacodynamic effects near Emax. It is possible that in the individual patient, an increase of the ruxolitinib dose is needed when initiating treatment with a strong enzyme inducer.
Other interactions to be considered affecting ruxolitinib
Mild or moderate CYP3A4 inhibitors (such as, but not limited to, ciprofloxacin, erythromycin, amprenavir, atazanavir, diltiazem, cimetidine)
In healthy subjects co-administration of ruxolitinib (10 mg single dose) with erythromycin 500 mg twice daily for four days resulted in ruxolitinib Cmax and AUC that were higher by 8% and 27%, respectively, than with ruxolitinib alone.
No dose adjustment is recommended when ruxolitinib is co-administered with mild or moderate CYP3A4 inhibitors (e.g. erythromycin). However, patients should be closely monitored for cytopenias when initiating therapy with a moderate CYP3A4 inhibitor.
Effects of ruxolitinib on other medicinal products
Oral contraceptives
There is no interaction study with oral contraceptives.
Substances metabolised by CYP3A4
It cannot be excluded that ruxolitinib inhibits CYP3A4 in the intestine. Increased systemic exposure may be obtained for substances which are metabolised by CYP3A4, and particularly those that undergo extensive intestinal metabolism. Safety monitoring of orally administered CYP3A4 metabolised substances is advised when combined with ruxolitinib. The interaction is likely to be minimised if the time between co-administrations is kept as long as possible.
Substances transported by P-glycoprotein or other transporters
Ruxolitinib may inhibit P-glycoprotein and breast cancer resistance protein (BCRP) in the intestine. This may result in increased sytemic exposure of substrates of these transporters, such as dabigatran etexilate, ciclosporin, rosuvastatin and potentially digoxin. Therapeutic drug monitoring (TDM) or clinical monitoring of the affected substance is advised.
It is possible that the potential inhibition of P-gp and BCRP in the intestine can be minimised if the time between administrations is kept apart as long as possible.
Haematopoietic growth factors
The concurrent use of haematopoietic growth factors and Jakavi has not been studied. It is not known whether the Janus Associated Kinase (JAK) inhibition by Jakavi reduces the efficacy of the haematopoietic growth factors or whether the haematopoietic growth factors affect the efficacy of Jakavi (see section 4.4).
Cytoreductive therapies
The concomitant use of cytoreductive therapies and Jakavi has not been studied. The safety and efficacy of this co-administration is not known (see section 4.4).
4.6 Fertility, pregnancy and lactation
Pregnancy and contraception in females
There are no data from the use of Jakavi in pregnant women.
Animal studies have shown that ruxolitinib is embryotoxic and foetotoxic. Teratogenicity was not observed in rats or rabbits. However, the exposure margins compared to the highest clinical dose were low and the results are therefore of limited relevance for humans (see section 5.3). The potential risk for humans is unknown. As a precautionary measure, the use of Jakavi during pregnancy is contraindicated (see section 4.3). Women of child-bearing potential should use effective contraception during the treatment with Jakavi. In case pregnancy should occur during treatment with Jakavi, a risk/benefit evaluation must be carried out on an individual basis with careful counselling regarding potential risks to the foetus (see section 5.3).
Breast-feeding
Jakavi must not be used during breast-feeding (see section 4.3) and breast-feeding should therefore be discontinued when treatment is started. It is unknown whether ruxolitinib and/or its metabolites are excreted in human milk. A risk to the breast-fed child cannot be excluded. Available pharmacodynamic/toxicological data in animals have shown excretion of ruxolitinib and its metabolites in milk (see section 5.3).
Fertility
There are no human data on the effect of ruxolitinib on fertility. In animal studies, no effect on fertility was observed.
4.7 Effects on ability to drive and use machines
Jakavi has no or negligible sedating effect. However, patients who experience dizziness after the intake of Jakavi should refrain from driving or using machines.
4.8 Undesirable effects
Summary of the safety profile
The most frequently reported adverse drug reactions were thrombocytopenia and anaemia.
Haematological adverse drug reactions (any Common Terminology Criteria for Adverse Events [CTCAE] grade) included anaemia (82.4%), thrombocytopenia (69.8%) and neutropenia (15.6%).
Anaemia, thrombocytopenia and neutropenia are dose-related effects.
The three most frequent non-haematological adverse drug reactions were bruising (21.3%), dizziness (15.0%) and headache (13.9%).
The three most frequent non-haematological laboratory abnormalities were raised alanine aminotransferase (26.9%), raised aspartate aminotransferase (19.3%) and hypercholesterolaemia (16.6%).
As expected with an extended follow-up period, the cumulative frequency of some adverse events increased in the evaluation of the 3-year follow-up safety data (median duration of exposure of 33.2 months in COMFORT-I and COMFORT-II for patients initially randomised to ruxolitinib) from 457 patients with myelofibrosis treated with ruxolitinib during the randomised and extension periods of the two pivotal phase 3 studies. This evaluation included data from patients that were initially randomised to ruxolitinib (N=301) and patients that received ruxolitinib after crossing over from control treatment arms (N=156). With these updated data, therapy discontinuation due to adverse events was observed in 17.1% of patients treated with ruxolitinib.
Tabulated summary of adverse drug reactions from clinical studies
In the clinical study programme the severity of adverse drug reactions was assessed based on the CTCAE, defining grade 1 = mild, grade 2 = moderate, grade 3 = severe and grade 4=life-threatening.
Adverse drug reactions from clinical studies (Table 1) are listed by MedDRA system organ class. Within each system organ class, the adverse drug reactions are ranked by frequency, with the most frequent reactions first. In addition, the corresponding frequency category for each adverse drug reaction is based on the following convention: very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000).
Table 1 Percentage of patients with adverse drug reactions in clinical studies*

Adverse drug reaction	Ruxolitinib – myelofibrosis patients N=301*
	All CTCAE gradesc (%)	CTCAE grade 3/4c (%)	Frequency category
Infections and infestations
Urinary tract infectionsa,d	12.3	1.0	Very common
Herpes zostera,d	4.3	0.3	Common
Tuberculosise	0.27	0.27	Uncommon
Blood and lymphatic system disordersb,d
Anaemia	82.4	42.5	Very common
Thrombocytopenia	69.8	11.3	Very common
Neutropenia	15.6	6.6	Very common
Bleeding (any bleeding including intracranial, and gastrointestinal bleeding, bruising and other bleeding)	32.6	4.7	Very common
Intracranial bleeding	1.0	1.0	Common
Gastrointestinal bleeding	5.0	1.3	Common
Bruising	21.3	0.3	Very common
Other bleeding (including epistaxis, post-procedural haemorrhage and haematuria)	13.3	2.3	Very common
Metabolism and nutrition disorders
Weight gaina	10.0	1.3	Very common
Hypercholesterolaemiab	16.6	0	Very common
Nervous system disorders
Dizzinessa	15.0	0.3	Very common
Headachea	13.9	0.5	Very common
Gastrointestinal disorders
Flatulencea	2.9	0	Common
Hepatobiliary disorders
Raised alanine aminotransferaseb	26.9	1.3	Very common
Raised aspartate aminotransferaseb	19.3	0	Very common
* Myelofibrosis patients randomised to and treated with ruxolitinib from the phase 3 pivotal COMFORT-I and COMFORT-II studies a Frequency is based on adverse event data. - A subject with multiple occurrence of an adverse drug reaction (ADR) is counted only once in that ADR category. - ADRs reported are on treatment or up to 28 days post treatment end date. b Frequency is based on laboratory values. - A subject with multiple occurrences of an ADR is counted only once in that ADR category. - ADRs reported are on treatment or up to 28 days post treatment end date. c Common Terminology Criteria for Adverse Events (CTCAE) version 3.0; grade 1 = mild, grade 2 = moderate, grade 3 = severe, grade 4 = life-threatening d These ADRs are discussed in the text. e Frequency is based on all patients exposed to ruxolitinib in clinical trials (N=4755)

Upon discontinuation, patients may experience a return of myelofibrosis symptoms such as fatigue, bone pain, fever, pruritus, night sweats, symptomatic splenomegaly and weight loss. In clinical studies the total symptom score for myelofibrosis symptoms gradually returned to baseline value within 7 days after dose discontinuation (see section 4.4).
Description of selected adverse drug reactions
Anaemia
In phase 3 clinical studies, median time to onset of first CTCAE grade 2 or higher anaemia was 1.5 months. One patient (0.3%) discontinued treatment because of anaemia.
In patients receiving Jakavi mean decreases in haemoglobin reached a nadir of approximately 10 g/litre below baseline after 8 to 12 weeks of therapy and then gradually recovered to reach a new steady state that was approximately 5 g/litre below baseline. This pattern was observed in patients regardless of whether they had received transfusion during therapy.
In the randomised, placebo-controlled study COMFORT-I 60.6% of Jakavi-treated patients and 37.7% of placebo-treated patients received red blood cell transfusions during randomised treatment. In the COMFORT-II study the rate of packed red blood cell transfusions was 53.4% in the Jakavi arm and 41.1% in the best available therapy arm.
Thrombocytopenia
In the phase 3 clinical studies, in patients who developed grade 3 or 4 thrombocytopenia, the median time to onset was approximately 8 weeks. Thrombocytopenia was generally reversible with dose reduction or dose interruption. The median time to recovery of platelet counts above 50,000/mm3 was 14 days. During the randomised period, platelet transfusions were administered to 4.7% of patients receiving Jakavi and to 4.0% of patients receiving control regimens. Discontinuation of treatment because of thrombocytopenia occurred in 0.7% of patients receiving Jakavi and 0.9% of patients receiving control regimens. Patients with a platelet count of 100,000/mm3 to 200,000/mm3 before starting Jakavi had a higher frequency of grade 3 or 4 thrombocytopenia compared to patients with platelet count >200,000/mm3 (64.2% versus 38.5%).
Neutropenia
In the phase 3 clinical studies, in patients who developed grade 3 or 4 neutropenia, the median time to onset was 12 weeks. During the randomised period, dose holding or reductions due to neutropenia were reported in 1.0% of patients, and 0.3% of patients discontinued treatment because of neutropenia.
Bleeding
In the phase 3 pivotal studies bleeding events (including intracranial and gastrointestinal, bruising and other bleeding events) were reported in 32.6% of patients exposed to Jakavi and 23.2% of patients exposed to the reference treatments (placebo or best available therapy). The frequency of grade 3-4 events was similar for patients treated with Jakavi or reference treatments (4.7% versus 3.1%). Most of the patients with bleeding events during the treatment reported bruising (65.3%). Bruising events were more frequently reported in patients taking Jakavi compared with the reference treatments (21.3% versus 11.6%). Intracranial bleeding was reported in 1% of patients exposed to Jakavi and 0.9% exposed to reference treatments. Gastrointestinal bleeding was reported in 5.0% of patients exposed to Jakavi compared to 3.1% exposed to reference treatments. Other bleeding events (including events such as epistaxis, post-procedural haemorrhage and haematuria) were reported in 13.3% of patients treated with Jakavi and 10.3% treated with reference treatments.
Infections
In the phase 3 pivotal studies grade 3 or 4 urinary tract infection was reported in 1.0% of patients, herpes zoster in 4.3% and tuberculosis in 1.0%.
Increased systolic blood pressure
In the phase 3 pivotal clinical studies an increase in systolic blood pressure of 20 mmHg or more from baseline was recorded in 31.5% of patients on at least one visit compared with 19.5% of the control-treated patients. In COMFORT-I the mean increase from baseline in systolic BP was 0-2 mmHg on Jakavi versus a decrease of 2-5 mmHg in the placebo arm. In COMFORT-II mean values showed little difference between the ruxolitinib-treated and the control-treated patients.
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard.
4.9 Overdose
There is no known antidote for overdoses with Jakavi. Single doses up to 200 mg have been given with acceptable acute tolerability. Higher than recommended repeat doses are associated with increased myelosuppression including leukopenia, anaemia and thrombocytopenia. Appropriate supportive treatment should be given.
Haemodialysis is not expected to enhance the elimination of ruxolitinib.
5. Pharmacological properties
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Antineoplastic agents, protein kinase inhibitors, ATC code: L01XE18
Mechanism of action
Ruxolitinib is a selective inhibitor of the Janus Associated Kinases (JAKs) JAK1 and JAK2 (IC50 values of 3.3 nM and 2.8 nM for JAK1 and JAK2 enzymes, respectively). These mediate the signalling of a number of cytokines and growth factors that are important for haematopoiesis and immune function.
Myelofibrosis is a myeloproliferative neoplasm known to be associated with dysregulated JAK1 and JAK2 signalling. The basis for the dysregulation is believed to include high levels of circulating cytokines that activate the JAK-STAT pathway, gain-of-function mutations such as JAK2V617F, and silencing of negative regulatory mechanisms. Myelofibrosis patients exhibit dysregulated JAK signalling regardless of JAK2V617F mutation status.
Ruxolitinib inhibits JAK-STAT signalling and cell proliferation of cytokine-dependent cellular models of haematological malignancies, as well as of Ba/F3 cells rendered cytokine-independent by expressing the JAK2V617F mutated protein, with IC50 ranging from 80-320 nM.
Pharmacodynamic effects
Ruxolitinib inhibits cytokine-induced STAT3 phosphorylation in whole blood from healthy subjects and myelofibrosis patients. Ruxolitinib resulted in maximal inhibition of STAT3 phosphorylation 2 hours after dosing which returned to near baseline by 8 hours in both healthy subjects and myelofibrosis patients, indicating no accumulation of either parent or active metabolites.
Baseline elevations in inflammatory markers associated with constitutional symptoms such as TNFα, IL-6 and CRP in subjects with myelofibrosis were decreased following treatment with ruxolitinib. Myelofibrosis patients did not become refractory to the pharmacodynamic effects of ruxolitinib treatment over time.
In a thorough QT study in healthy subjects, there was no indication of a QT/QTc prolonging effect of ruxolitinib in single doses up to a supratherapeutic dose of 200 mg, indicating that ruxolitinib has no effect on cardiac repolarisation.
Clinical efficacy and safety
Two randomised phase 3 studies (COMFORT-I and COMFORT-II) were conducted in patients with myelofibrosis (primary myelofibrosis, post-polycythaemia vera myelofibrosis or post-essential thrombocythaemia myelofibrosis). In both studies, patients had palpable splenomegaly at least 5 cm below the costal margin and risk category of intermediate-2 (2 prognostic factors) or high risk (3 or more prognostic factors) based on the International Working Group (IWG) Consensus Criteria. The starting dose of Jakavi was based on platelet count.
COMFORT-I was a double-blind, randomised, placebo-controlled study in 309 patients who were refractory to or were not candidates for available therapy. Patients were given Jakavi or matching placebo. The primary efficacy endpoint was proportion of subjects achieving ≥35% reduction from baseline in spleen volume at week 24 as measured by Magnetic Resonance Imaging (MRI) or Computed Tomography (CT).
Secondary endpoints included duration of maintenance of a ≥35% reduction from baseline in spleen volume, proportion of patients who had ≥50% reduction in total symptom score from baseline to week 24 as measured by the modified Myelofibrosis Symptom Assessment Form (MFSAF) v2.0 diary, change in total symptom score from baseline to week 24 as measured by the modified MFSAF v2.0 diary, and overall survival.
COMFORT-II was an open-label, randomised study in 219 patients. Patients were randomised 2:1 to Jakavi versus best available therapy. Best available therapy was selected by the investigator on a patient-by-patient basis. In the best available therapy arm, 47% of patients received hydroxyurea and 16% of patients received glucocorticoids. The primary efficacy endpoint was proportion of patients achieving ≥35% reduction from baseline in spleen volume at week 48 as measured by MRI or CT.
A secondary endpoint in COMFORT-II was the proportion of patients achieving a ≥35% reduction of spleen volume measured by MRI or CT from baseline to week 24. Duration of maintenance of a ≥35% reduction from baseline in responding patients was also a secondary endpoint.
In COMFORT-I and COMFORT-II, patient baseline demographics and disease characteristics were comparable between the treatment arms.
Table 2 Percentage of patients with ≥35% reduction from baseline in spleen volume at week 24 in COMFORT-I and at week 48 in COMFORT-II (ITT)

COMFORT-I		COMFORT-II
	Jakavi (N=155)	Placebo (N=153)	Jakavi (N=144)	Best available therapy (N=72)
Time points	Week 24		Week 48
Number (%) of subjects with spleen volume reduced by ≥35%	65 (41.9)	1 (0.7)	41 (28.5)	0
95% confidence intervals	34.1, 50.1	0, 3.6	21.3, 36.6	0.0, 5.0
p-value	<0.0001		<0.0001

A significantly higher proportion of patients in the Jakavi group achieved ≥35% reduction from baseline in spleen volume (Table 2) regardless of the presence or absence of the JAK2V617F mutation or the disease subtype (primary myelofibrosis, post-polycythaemia vera myelofibrosis, post-essential thrombocythaemia myelofibrosis).
Table 3 Percentage of patients with ≥35% reduction from baseline in spleen volume by JAK mutation status (safety set)

COMFORT-I				COMFORT-II
	Jakavi		Placebo		Jakavi		Best available therapy
JAK mutation status	Positive (N=113) n (%)	Negative (N=40) n (%)	Positive (N=121) n (%)	Negative (N=27) n (%)	Positive (N=110) n (%)	Negative (N=35) n (%)	Positive (N=49) n (%)	Negative (N=20) n (%)
Number (%) of subjects with spleen volume reduced by ≥35%	54 (47.8)	11 (27.5)	1 (0.8)	0	36 (32.7)	5 (14.3)	0	0
Time point	After 24 weeks				After 48 weeks

Among the 80 patients in COMFORT-I and the 69 patients in COMFORT-II who showed a ≥35% reduction at any time point, the probability that a patient would maintain a response on Jakavi for at least 24 weeks was 89% and 87%, respectively, while the probability of maintaining a response for at least 48 weeks was 52% in COMFORT-II.
Jakavi improves myelofibrosis-associated symptoms and quality of life in patients with myelofibrosis. In COMFORT-I symptoms of myelofibrosis were captured using the modified MFSAF diary v2.0 as an electronic diary which subjects completed daily. A significantly larger proportion of subjects in the Jakavi group achieved a ≥50% improvement from baseline in the week 24 total symptom score compared with the placebo group (45.9% and 5.3%, respectively, p<0.0001 using the chi-square test).
An improvement in overall quality of life was measured by a validated instrument, the EORTC QLQ-C30 in both COMFORT-I and COMFORT-II. At week 24 in COMFORT-I the mean change for the global health status/quality of life score was +12.3 and -3.4 (p<0.0001) for Jakavi and placebo, respectively.
In COMFORT-I, after a median follow-up of 34.3 months, the death rate in patients randomised to the ruxolitinib arm was 27.1% versus 35.1% in patients randomised to placebo; HR 0.687; 95% CI 0.459 1.029; p=0.0668. In COMFORT-II, after a median follow up of 34.7 months, the death rate in patients randomised to ruxolitinib was 19.9% versus 30.1% in patients randomised to best available treatment (BAT); HR 0.48; 95% CI 0.28 0.85; p=0.009. In both studies, the lower death rates noted in the ruxolitinib arm were predominantly driven by the results obtained in the post polycythaemia vera and post essential thrombocythaemia subgroups.
Paediatric population
The European Medicines Agency has waived the obligation to submit the results of studies with Jakavi in all subsets of the paediatric population for the treatment of myelofibrosis (see section 4.2 for information on paediatric use).
5.2 Pharmacokinetic properties
Aborption
Ruxolitinib is a Biopharmaceutical Classification System (BCS) class 1 compound, with high permeability, high solubility and rapid dissolution characteristics. In clinical studies, ruxolitinib is rapidly absorbed after oral administration with maximal plasma concentration (Cmax) achieved approximately 1 hour post-dose. Based on a human mass balance study, oral absorption of ruxolitinib, as ruxolitinib or metabolites formed under first-pass, is 95% or greater. Mean ruxolitinib Cmax and total exposure (AUC) increased proportionally over a single dose range of 5-200 mg. There was no clinically relevant change in the pharmacokinetics of ruxolitinib upon administration with a high-fat meal. The mean Cmax was moderately decreased (24%) while the mean AUC was nearly unchanged (4% increase) on dosing with a high-fat meal.
Distribution
The apparent volume of distribution at steady state is 53-65 litres in myelofibrosis patients. At clinically relevant concentrations of ruxolitinib, binding to plasma proteins in vitro is approximately 97%, mostly to albumin. A whole body autoradiography study in rats has shown that ruxolitinib does not penetrate the blood-brain barrier.
Biotransformation
Ruxolitinib is mainly metabolised by CYP3A4 (>50%), with additional contribution from CYP2C9. Parent compound is the predominant entity in human plasma, representing approximately 60% of the drug-related material in circulation. Two major and active metabolites are present in plasma representing 25% and 11% of parent AUC. These metabolites have one half to one fifth of the parent JAK-related pharmacological activity. The sum total of all active metabolites contributes to 18% of the overall pharmacodynamics of ruxolitinib. At clinically relevant concentrations, ruxolitinib does not inhibit CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 or hepatic CYP3A4 and is not a potent inducer of CYP1A2, CYP2B6 or CYP3A4 based on in vitro studies. In vitro data indicate that ruxolitinib may inhibit intestinal CYP3A4, P-gp and BCRP.
Elimination
Ruxolitinib is mainly eliminated through metabolism. The mean elimination half-life of ruxolitinib is approximately 3 hours. Following a single oral dose of [14C]-labelled ruxolitinib in healthy adult subjects, elimination was predominately through metabolism, with 74% of radioactivity excreted in urine and 22% via faeces. Unchanged parent substance accounted for less than 1% of the excreted total radioactivity.
Linearity/non-linearity
Dose proportionality was demonstrated in the single and multiple dose studies.
Special populations
Effects of age, gender or race
In healthy subjects, no significant differences in ruxolitinib pharmacokinetics were observed with regard to gender and race. In a population pharmacokinetic evaluation in myelofibrosis patients, no relationship was apparent between oral clearance and patient age or race. The predicted oral clearance was 17.7 l/h in women and 22.1 l/h in men, with 39% inter-subject variability.
Paediatric population
The safety and effectiveness of Jakavi in paediatric patients have not been established (see section 5.1, “Paediatric population”).
Renal impairment
Renal function was determined using both Modification of Diet in Renal Disease (MDRD) and urinary creatinine. Following a single ruxolitinib dose of 25 mg, the exposure of ruxolitinib was similar in subjects with various degrees of renal impairment and in those with normal renal function. However, plasma AUC values of ruxolitinib metabolites tended to increase with increasing severity of renal impairment, and were most markedly increased in the subjects with severe renal impairment. It is unknown whether the increased metabolite exposure is of safety concern. A dose modification is recommended in patients with severe renal impairment and end-stage renal disease (see section 4.2). Dosing only on dialysis days reduces the metabolite exposure, but also the pharmacodynamic effect, especially on the days between dialysis.
Hepatic impairment
Following a single ruxolitinib dose of 25 mg in patients with varying degrees of hepatic impairment, the mean AUC for ruxolitinib was increased in patients with mild, moderate and severe hepatic impairment by 87%, 28% and 65%, respectively, compared to patients with normal hepatic function. There was no clear relationship between AUC and the degree of hepatic impairment based on Child-Pugh scores. The terminal elimination half-life was prolonged in patients with hepatic impairment compared to healthy controls (4.1-5.0 hours versus 2.8 hours). A dose reduction of approximately 50% is recommended for patients with hepatic impairment (see section 4.2).
5.3 Preclinical safety data
Ruxolitinib has been evaluated in safety pharmacology, repeated dose toxicity, genotoxicity and reproductive toxicity studies and in a carcinogenicity study. Target organs associated with the pharmacological action of ruxolitinb in repeated dose studies include bone marrow, peripheral blood and lymphoid tissues. Infections generally associated with immunosuppression were noted in dogs. Adverse decreases in blood pressure along with increases in heart rate were noted in a dog telemetry study, and an adverse decrease in minute volume was noted in a respiratory study in rats. The margins (based on unbound Cmax) at the non-adverse level in the dog and rat studies were 15.7-fold and 10.4-fold greater, respectively, than the maximum human recommended dose of 25 mg twice daily. No effects were noted in an evaluation of the neuropharmacological effects of ruxolitinib.
Ruxolitinib decreased foetal weight and increased post-implantation loss in animal studies. There was no evidence of a teratogenic effect in rats and rabbits. However, the exposure margins compared to the highest clinical dose were low and the results are therefore of limited relevance for humans. No effects were noted on fertility. In a pre- and post-natal development study, a slightly prolonged gestation period, reduced number of implantation sites, and reduced number of pups delivered were observed. In the pups, decreased mean initial body weights and short period of decreased mean body weight gain were observed. In lactating rats, ruxolitinib and/or its metabolites were excreted into the milk with a concentration that was 13-fold higher than the maternal plasma concentration. Ruxolitinib was not mutagenic or clastogenic. Ruxolitinib was not carcinogenic in the Tg.rasH2 transgenic mouse model.
6. Pharmaceutical particulars
6.1 List of excipients
Cellulose, microcrystalline
Magnesium stearate
Silica, colloidal anhydrous
Sodium starch glycolate (Type A)
Povidone
Hydroxypropylcellulose
Lactose monohydrate
6.2 Incompatibilities
Not applicable.
6.3 Shelf life
Blisters
2 years
Bottles
2 years
After first-opening: 1 month
6.4 Special precautions for storage
Do not store above 30°C.
6.5 Nature and contents of container
PVC/PCTFE/Aluminium blister packs containing 14 or 56 tablets or multipacks containing 168 (3 packs of 56) tablets.
HDPE bottle with induction seal and child-resistant closure containing 60 tablets.
Not all pack sizes or types may be marketed.
6.6 Special precautions for disposal and other handling
No special requirements.
7. Marketing authorisation holder
Novartis Europharm Limited
Wimblehurst Road
Horsham
West Sussex, RH12 5AB
United Kingdom
8. Marketing authorisation number(s)
EU/1/12/773/001 Jakavi 5 mg
EU/1/12/773/004 Jakavi 5 mg
EU/1/12/773/005 Jakavi 5 mg
EU/1/12/773/006 Jakavi 5 mg
EU/1/12/773/002 Jakavi 15 mg
EU/1/12/773/007 Jakavi 15 mg
EU/1/12/773/008 Jakavi 15 mg
EU/1/12/773/009 Jakavi 15 mg
EU/1/12/773/003 Jakavi 20 mg
EU/1/12/773/010 Jakavi 20 mg
EU/1/12/773/011 Jakavi 20 mg
EU/1/12/773/012 Jakavi 20 mg
EU/1/12/773/013 Jakavi 10 mg
EU/1/12/773/014 Jakavi 10 mg
EU/1/12/773/015 Jakavi 10 mg
EU/1/12/773/016 Jakavi 10 mg
9. Date of first authorisation/renewal of the authorisation
23 August 2012
10. Date of revision of the text
03 October 2014
Detailed information on this medicinal product is available on the website of the European Medicines Agency http://www.ema.europa.eu

Jakavi在美获批为真性红细胞增多症二线用药
美国监管机构已经批准了诺华公司和Incyte公司的JAK1、2抑制剂Jakavi（ruxolitinib）用于真性红细胞增多症，使之成为美国首个特别批准用于此症的药物。
真性红细胞增多症是一种慢性和不可治愈的病症，特征为骨髓中红血细胞过剩，这可能会导致脾肿，近皮肤表面出血和静脉附件产生血凝块（静脉炎）。这种病症也使患者中风或心脏病发作的风险增加。
Jakafi获得了孤儿药的认定，能够抑制Janus相关激酶（JAK）1和2发挥作用，JAK酶参与调节血液和免疫功能。
美国食品和药物管理局根据该药物的临床试验数据给予批准，与一线治疗药物相比，Jakavi无需抽血而能维持红细胞量，减少患者脾脏大小，是无法进行羟基脲化疗患者的福音。
Jakavi于2011年被FDA首次批准用于治疗骨髓纤维化，当时普遍预计该药物能一鸣惊人；该药物现在也正在试验治疗胰腺癌.