Summary of medicine characteristics - Nityr
1. NAME OF THE MEDICINAL PRODUCT
Nityr 10 mg tablets
2. QUALITATIVE AND QUANTITATIVE COMPOSITION
Each tablet contains 10 mg nitisinone.
Excipient with known effect
Each tablet contains less than 120 mg of lactose (as monohydrate).
For the full list of excipients, see section 6.1.
3. PHARMACEUTICAL FORM
Tablet.
White to beige, round (7 × 2.3 mm), flat tablets which may display light yellow to brown speckles, marked “10” on one side and “L” on the other side.
4. CLINICAL PARTICULARS4.1 Therapeutic indications
Nityr is indicated for the treatment of adult and paediatric patients with confirmed diagnosis of hereditary tyrosinemia type 1 (HT-1) in combination with dietary restriction of tyrosine and phenylalanine.
4.2 Posology and method of administration
Posology
Nitisinone treatment should be initiated and supervised by a physician experienced in the treatment of HT-1 patients.
Treatment of all genotypes of the disease should be initiated as early as possible to increase overall survival and avoid complications such as liver failure, liver cancer and renal disease. Adjunct to the nitisinone treatment, a diet deficient in phenylalanine and tyrosine is required and should be followed by monitoring of plasma amino acids (see sections 4.4 and 4.8).
Starting dose
The recommended initial daily dose in the paediatric and adult population is 1 mg/kg body weight administered orally. The dose of nitisinone should be adjusted individually. It is recommended to administer the dose once daily. However, due to the limited data in patients with body weight <20 kg, it is recommended to divide the total daily dose into two daily administrations in this patient population.
Dose adjustment
During regular monitoring, it is appropriate to follow urine succinylacetone, liver function test values and alpha-fetoprotein levels (see section 4.4). If urine succinylacetone is still detectable one month after the start of nitisinone treatment, the nitisinone dose should be increased to 1.5 mg/kg body weight/day. A dose of 2 mg/kg body weight/day may be needed based on the evaluation of all biochemical parameters. This dose should be considered as a maximal dose for all patients.
If the biochemical response is satisfactory, the dose should be adjusted only according to body weight gain.
However, in addition to the tests above, during the initiation of therapy, switch from twice daily to once daily dosing or if there is a deterioration, it may be necessary to follow more closely all available biochemical parameters (i.e. plasma succinylacetone, urine 5-aminolevulinate (ALA) and erythrocyte porphobilinogen (PBG)-synthase activity).
Special populations
There are no specific dose recommendations for elderly or patients that have renal or hepatic impairment.
Paediatric population
The dose recommendation in mg/kg body weight is the same in children and adults.
However, due to the limited data in patients with body weight <20 kg, it is recommended to divide the total daily dose into two daily administrations in this patient population.
Method of administration
The tablets may be taken with or without food. Tablets are not suitable for breaking to make up additional strengths.
For patients who require additional strengths (i.e. between multiples of 10 mg or lower than 10 mg) other medicinal products with lower strengths are available.
For paediatric patients who have difficulties swallowing tablets, other pharmaceutical forms are available.
4.3 Contraindications
Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.
Mothers receiving nitisinone must not breast-feed (see sections 4.6 and 5.3).
4.4 Special warnings and precautions for use
Monitoring visits should be performed every 6 months; shorter intervals between visits are recommended in case of adverse events.
Monitoring of plasma tyrosine levels
It is recommended that a slit-lamp examination of the eyes is performed before initiation of nitisinone treatment and thereafter regularly, at least once a year. A patient displaying visual disorders during treatment with nitisinone should without delay be examined by an ophthalmologist. It should be established that the patient is adhering to his/her dietary regimen and the plasma tyrosine concentration should be measured. A more restricted tyrosine and phenylalanine diet should be implemented in case the plasma tyrosine level is above 500 micromol/l. It is not recommended to lower the plasma tyrosine concentration by reduction or discontinuation of nitisinone, since the metabolic defect may result in deterioration of the patient’s clinical condition.
Liver monitoring
The liver function should be monitored regularly by liver function tests and liver imaging. It is recommended to also monitor serum alpha-fetoprotein concentrations. Increase in serum alpha-fetoprotein concentration may be a sign of inadequate treatment. Patients with increasing alpha-fetoprotein or signs of nodules in the liver should always be evaluated for hepatic malignancy.
Platelet and white blood cell (WBC) monitoring
It is recommended that platelet and WBC counts are monitored regularly, as a few cases of reversible thrombocytopenia and leucopenia were observed during clinical evaluation.
Lactose
Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicinal product.
Concomitant use with other medicinal products
Nitisinone is a moderate CYP2C9 inhibitor. Nitisinone treatment may therefore result in increased plasma concentrations of co-administered medicinal products metabolized primarily via CYP2C9. Nitisinone treated patients who are concomitantly treated with medicinal products with a narrow therapeutic window metabolized through CYP2C9, such as warfarin and phenytoin, should be carefully monitored. Dose-adjustment of these co-administered medicinal products may be needed (see section 4.5).
4.5 Interaction with other medicinal products and other forms of interaction
Nitisinone is metabolised in vitro by CYP3A4 and dose-adjustment may therefore be needed when nitisinone is co-administered with inhibitors or inducers of this enzyme.
Based on data from a clinical interaction study with 80 mg nitisinone at steady-state, nitisinone is a moderate inhibitor of CYP2C9 (2.3-fold increase in tolbutamide AUC), therefore nitisinone treatment may result in increased plasma concentrations of co-administered medicinal products metabolized primarily via CYP2C9 (see section 4.4).
Nitisinone is a weak inducer of CYP2E1 (30% decrease in chlorzoxazone AUC) and a weak inhibitor of OAT1 and OAT3 (1.7-fold increase in AUC of furosemide), whereas nitisinone did not inhibit CYP2D6 (see section 5.2).
A food effect study has been conducted with Nityr. The study demonstrated that Nityr can be administered with or without food without affecting its bioavailability.
4.6 Fertility, pregnancy and lactation
Pregnancy
There are no adequate data from the use of nitisinone in pregnant women. Studies in animals have shown reproductive toxicity (see section 5.3). The potential risk for humans is unknown. Nityr should not be used during pregnancy unless the clinical condition of the woman requires treatment with nitisinone. Nitisinone crosses the human placenta.
Breast-feeding
It is unknown whether nitisinone is excreted in human breast milk. Animal studies have shown adverse postnatal effects via exposure of nitisinone in milk. Therefore, mothers receiving nitisinone must not breast-feed, since a risk to the suckling child cannot be excluded (see sections 4.3 and 5.3).
Fertility
There are no data on nitisinone affecting fertility.
4.7 Effects on ability to drive and use machines
Nityr has minor influence on the ability to drive and use machines. Adverse reactions involving the eyes (see section 4.8) can affect the vision. If the vision is affected the patient should not drive or use machines until the event has subsided.
4.8 Undesirable effects
Summary of the safety profile
By its mode of action, nitisinone increases tyrosine levels in all nitisinone treated patients. Eye-related adverse reactions, such as conjunctivitis, corneal opacity, keratitis, photophobia, and eye pain, related to elevated tyrosine levels are therefore common. Other common adverse reactions include thrombocytopenia, leucopenia, and granulocytopenia. Exfoliative dermatitis may occur uncommonly.
Tabulated list of adverse reactions
The adverse reactions listed below by MedDRA system organ class and absolute frequency, are based on data from a clinical trial and post-marketing use. Frequency is defined as 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), not known (cannot be estimated from the available data). Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.
| MedDRA system organ class | Frequency | Adverse reaction |
| Blood and lymphatic system disorders | Common | Thrombocytopenia, leucopenia, granulocytopenia |
| Uncommon | Leukocytosis | |
| Eye disorders | Common | Conjunctivitis, corneal opacity, keratitis, photophobia, eye pain |
| Uncommon | Blepharitis | |
| Skin and subcutaneous tissue disorders | Uncommon | Exfoliative dermatitis, erythematous rash, pruritus, rash |
| Investigations | Very common | Elevated tyrosine levels |
Description of selected adverse reactions
Nitisinone treatment leads to elevated tyrosine levels. Elevated levels of tyrosine have been associated with eye-related adverse reactions, such as e.g. corneal opacities and hyperkeratotic lesions.
Restriction of tyrosine and phenylalanine in the diet should limit the toxicity associated with this type of tyrosinemia by lowering tyrosine levels (see section 4.4).
In clinical studies, granulocytopenia was only uncommonly severe (<0.5×109/L) and not associated with infections. Adverse reactions affecting the MedDRA system organ class ‘Blood and lymphatic system disorders’ subsided during continued nitisinone treatment.
Paediatric population
The safety profile is mainly based on the paediatric population since nitisinone treatment should be started as soon as the diagnosis of hereditary tyrosinemia type 1 (HT-1) has been established. From clinical study and post marketing data there are no indications that the safety profile is different in different subsets of the paediatric population or different from the safety profile in adult 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 national reporting system listed in Appendix V.
4.9 Overdose
Accidental ingestion of nitisinone by individuals eating normal diets not restricted in tyrosine and phenylalanine will result in elevated tyrosine levels. Elevated tyrosine levels have been associated with toxicity to eyes, skin, and the nervous system. Restriction of tyrosine and phenylalanine in the diet should limit toxicity associated with this type of tyrosinemia. No information about specific treatment of overdose is available.
5. PHARMACOLOGICAL PROPERTIES5.1 Pharmacodynamic properties
Pharmacotherapeutic group: Other alimentary tract and metabolism products, Various alimentary tract and metabolism products, ATC code: A16AX04.
Mechanism of action
Nitisinone is a competitive inhibitor of 4-hydroxyphenylpyruvate dioxygenase, the second step in the tyrosine metabolism. By inhibiting the normal catabolism of tyrosine in patients with HT-1, nitisinone prevents the accumulation of harmful metabolites downstream of 4-hydroxyphenylpyruvate dioxygenase.
The biochemical defect in HT-1 is a deficiency of fumarylacetoacetate hydrolase, which is the final enzyme of the tyrosine catabolic pathway. Nitisinone prevents the accumulation of the toxic intermediates maleylacetoacetate and fumarylacetoacetate. These intermediates are otherwise converted to the toxic metabolites succinylacetone and succinylacetoacetate. Succinylacetone inhibits the porphyrin synthesis pathway leading to the accumulation of 5-aminolevulinate.
Pharmacodynamic effects
Nitisinone treatment leads to normalised porphyrin metabolism with normal erythrocyte porphobilinogen synthase activity and urine 5-aminolevulinate, decreased urinary excretion of succinylacetone, increased plasma tyrosine concentration and increased urinary excretion of phenolic acids. Available data from a clinical study indicates that in more than 90% of the patients urine succinylacetone was normalised during the first week of treatment. Succinylacetone should not be detectable in urine or plasma when the nitisinone dose is properly adjusted.
Clinical efficacy and safety
The clinical study was open-labelled and uncontrolled. The dosing frequency in the study was twice daily. Survival probabilities after 2, 4 and 6 years of treatment with nitisinone are summarised in the table below.
| NTBC study (N=250) | |||
| Age at start of treatment | 2 years | 4 years | 6 years |
| < 2 months | 93% | 93% | 93% |
| < 6 months | 93% | 93% | 93% |
| > 6 months | 96% | 95% | 95% |
| Overall | 94% | 94% | 94% |
Data from a study used as a historical control (van Spronsen et al., 1994) showed the following survival probability.
| Age at onset of symptoms | 1 year | 2 years |
| < 2 months | 38% | 29% |
| > 2–6 months | 74% | 74% |
| > 6 months | 96% | 96% |
Treatment with nitisinone was also found to result in reduced risk for the development of hepatocellular carcinoma compared to historical data on treatment with dietary restriction alone. It was found that the early initiation of treatment resulted in a further reduced risk for the development of hepatocellular carcinoma.
The 2-, 4-, and 6-year probability of no occurrence of HCC during nitisinone treatment for patients aged 24 months or younger at the start of treatment and for those older than 24 months at the start of treatment is shown in the following table:
| NTBC study (N=250) | |||||||
| Number of patients at | Probability of no HCC (95% confidence interval) at | ||||||
| Start | 2 years | 4 years | 6 years | 2 years | 4 years | 6 years | |
| All patients | 250 | 155 | 86 | 15 | 98% (95; 100) | 94% (90; 98) | 91% (81; 100) |
| Start age < 24 months | 193 | 114 | 61 | 8 | 99% (98; 100) | 99% (97; 100) | 99% (94; 100) |
| Start age > 24 months | 57 | 41 | 25 | 8 | 92% (84; 100) | 82% (70;95) | 75% (56; 95) |
In an international survey of patients with HT-1 on treatment with dietary restriction alone, it was found that HCC had been diagnosed in 18% of all patients aged 2 years and above.
A study to evaluate the PK, efficacy and safety of once daily dosing compared to twice daily dosing was performed in 19 patients with HT-1. There were no clinically important differences in AEs or other safety assessments between once and twice daily dosing. No patient had detectable succinylacetone (SA) levels at the end of the once-daily treatment period. The study indicates that once daily administration is safe and efficacious across all ages of patients. Data is, however, limited in patients with body weight <20 kg.
5.2 Pharmacokinetic properties
Formal absorption, distribution, metabolism and elimination studies have not been performed with nitisinone. In 23 healthy volunteers, after administration of a single dose of Nityr tablets (10 mg) the terminal half-life (median) of nitisinone in plasma was 59 hours (ranging from 41 to 74 hours).
A population pharmacokinetic analysis has been conducted on a group of 207 HT-1 patients. The clearance and half-life were determined to be 0.0956 l/kg body weight/day and 52.1 hours respectively.
In vitro studies using human liver microsomes and cDNA-expressed P450 enzymes have shown limited CYP3A4-mediated metabolism.
Based on data from a clinical interaction study with 80 mg nitisinone at steady-state, nitisinone caused a 2.3-fold increase in AUG, of the CYP2C9 substrate tolbutamide, which is indicative of a moderate inhibition of CYP2C9. Nitisinone caused an approximate 30% decrease in chlorzoxazone AUC,, indicative of a weak induction of CYP2E1. Nitisinone does not inhibit CYP2D6 since metoprolol AUC, was not affected by the administration of nitisinone. Furosemide AUC, was increased 1.7-fold, indicating a weak inhibition of OAT1/OAT3 (see sections 4.4 and 4.5).
Based on in vitro studies, nitisinone is not expected to inhibit CYP1A2, 2C19 or 3A4-mediated metabolism or to induce CYP1A2, 2B6 or 3A4/5. Nitisinone is not expected to inhibit P-gp, BCRP or OCT2-mediated transport. Nitisinone plasma concentration reached in clinical setting is not expected to inhibit OATP1B1, OATP1B3 mediated transport.
5.3 Preclinical safety data
Nitisinone has shown embryo-foetal toxicity in the mouse and rabbit at clinically relevant dose levels. In the rabbit, nitisinone induced a dose-related increase in malformations (umbilical hernia and gastroschisis) from a dose level 2.5-fold higher than the maximum recommended human dose (2 mg/kg/day).
A pre- and postnatal development study in the mouse showed statistically significantly reduced pup survival and pup growth during the weaning period at dose levels 125– and 25-fold higher, respectively, than the maximum recommended human dose, with a trend toward a negative effect on pup survival starting from the dose of 5 mg/kg/day. In rats, exposure via milk resulted in reduced mean pup weight and corneal lesions.
No mutagenic but a weak clastogenic activity was observed in in vitro studies. There was no evidence of in vivo genotoxicity (mouse micronucleus assay and mouse liver unscheduled DNA synthesis assay). Nitisinone did not show carcinogenic potential in a 26-week carcinogenicity study in transgenic mice (TgrasH2).
6. PHARMACEUTICAL PARTICULARS6.1 List of excipients
Glycerol dibehenate
Lactose monohydrate
6.2 Incompatibilities
Not applicable.
6.3 Shelf life
3 years.
During the shelf life, the patient may store the bottle after first opening for a period of 2 months, after which the medicinal product must be discarded.
6.4 Special precautions for storage
This medicinal product does not require any special temperature storage conditions.
Store in the original bottle to protect from light.
For storage conditions after first opening of the medicinal product, see section 6.3.
6.5 Nature and contents of container
HDPE 75 mL square bottles with a tamper-evident child-resistant closure of polypropylene (PP). Each bottle contains 60 tablets. Each carton contains 1 bottle.
6.6 Special precautions for disposal
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
7. MARKETING AUTHORISATION HOLDER
Cycle Pharmaceuticals (Europe) Limited
70 Sir John Rogerson’s Quay
Dublin 2
D02 R296, Ireland
8. MARKETING AUTHORISATION NUMBER(S)
EU/1/18/1290/001
9. DATE OF FIRST AUTHORISATION/RENEWAL OF THE AUTHORISATION
Date of first authorisation: 26 July 2018