Progressive Multifocal Leukoencephalopathy (PML)
Use of TYSABRI has been associated with an increased risk of PML, an opportunistic infection caused by JC virus, which may be fatal or result in severe disability. Due to this increased risk of developing PML, the benefits and risks of TYSABRI treatment should be individually reconsidered by the specialist physician and the patient.
Patients should be instructed together with their caregivers on early signs and symptoms of PML.
Each of the following independent risk factors is associated with an increased risk of PML.
• Treatment duration, especially beyond 2 years. There is limited experience in patients who have received more than 4 years of TYSABRI treatment therefore the risk of PML in these patients cannot currently be estimated.
• Immunosuppressant use prior to receiving TYSABRI.
• The presence of anti-JCV antibodies.
Anti-JCV antibody status identifies different levels of risk for PML in TYSABRI treated patients. Patients who are anti-JCV antibody positive are at an increased risk of developing PML compared to patients who are anti-JCV antibody negative. Patients who have all three risk factors for PML (i.e., have received more than 2 years of TYSABRI therapy, and have received prior immunosuppressant therapy and are anti-JCV antibody positive) have the highest risk of PML at approximately 9 in 1,000 patients treated. Patients should be informed about this increased risk for developing PML before continuation of treatment after 2 years.
For risk stratification prior or during the treatment with TYSABRI anti-JCV antibody testing may provide supportive information.
Before initiation of treatment with TYSABRI, a recent (usually within 3 months) MRI should be available as a reference, and be repeated on a yearly routine basis to update this reference. Patients must be monitored at regular intervals throughout. After 2 years the patient should be re-informed about the risk of PML with TYSABRI.
If PML is suspected, further dosing must be suspended until PML has been excluded.
The clinician should eva luate the patient to determine if the symptoms are indicative of neurological dysfunction, and if so, whether these symptoms are typical of MS or possibly suggestive of PML. If any doubt exists, further eva luation, including MRI scan preferably with contrast (compared with pre-treatment MRI), CSF testing for JC Viral DNA and repeat neurological assessments, should be considered as described in the Physician Information and Management Guidelines (see educational guidance). Once the clinician has excluded PML (if necessary, by repeating clinical, imaging and/or laboratory investigations if clinical suspicion remains), dosing of natalizumab may resume.
The physician should be particularly alert to symptoms suggestive of PML that the patient may not notice (e.g. cognitive or psychiatric symptoms). Patients should also be advised to inform their partner or caregivers about their treatment, since they may notice symptoms that the patient is not aware of.
If a patient develops PML the dosing of TYSABRI must be permanently discontinued.
Following reconstitution of the immune system in immunocompromised patients with PML improved outcome has been seen.
PML and IRIS (Immune Reconstitution Inflammatory Syndrome)
IRIS occurs in almost all TYSABRI PML patients after withdrawal or removal of TYSABRI, e.g. by plasma exchange (see section 5.2). IRIS is thought to result from the restoration of immune function in patients with PML, which can lead to serious neurological complications and may be fatal. Monitoring for development of IRIS, which has occurred within days to several weeks after plasma exchange in TYSABRI treated patients with PML, and appropriate treatment of the associated inflammation during recovery from PML should be undertaken (see the Physician Information and Management Guidelines for further information).
Other Opportunistic Infections
Other opportunistic infections have been reported with use of TYSABRI, primarily in patients with Crohn's disease who were immunocompromised or where significant co-morbidity existed, however increased risk of other opportunistic infections with use of TYSABRI in patients without these co-morbidities cannot currently be excluded. Opportunistic infections were also detected in MS patients treated with TYSABRI as a monotherapy (see section 4.8).
Prescribers should be aware of the possibility that other opportunistic infections may occur during TYSABRI therapy and should include them in the differential diagnosis of infections that occur in TYSABRI-treated patients. If an opportunistic infection is suspected, dosing with TYSABRI is to be suspended until such infections can be excluded through further eva luations.
If a patient receiving TYSABRI develops an opportunistic infection, dosing of TYSABRI must be permanently discontinued.
Educational guidance
All physicians who intend to prescribe TYSABRI must ensure they are familiar with the Physician Information and Management Guidelines.
Physicians must discuss the benefits and risks of TYSABRI therapy with the patient and provide them with a Patient Alert Card. Patients should be instructed that if they develop any infection then they should inform their physician that they are being treated with TYSABRI.
Physicians should counsel patients on the importance of uninterrupted dosing, particularly in the early months of treatment (see hypersensitivity).
Hypersensitivity
Hypersensitivity reactions have been associated with TYSABRI, including serious systemic reactions (see section 4.8). These reactions usually occurred during the infusion or up to 1 hour after completion of the infusion. The risk for hypersensitivity was greatest with early infusions and in patients re-exposed to TYSABRI following an initial short exposure (one or two infusions) and extended period (three months or more) without treatment. However, the risk of hypersensitivity reactions should be considered for every infusion administered.
Patients are to be observed during the infusion and for 1 hour after the completion of the infusion (see section 4.8). Resources for the management of hypersensitivity reactions should be available.
Discontinue administration of TYSABRI and initiate appropriate therapy at the first symptoms or signs of hypersensitivity.
Patients who have experienced a hypersensitivity reaction must be permanently discontinued from treatment with TYSABRI.
Concurrent or prior treatment with immunosuppressants
The safety and efficacy of TYSABRI in combination with other immunosuppressive and antineoplastic therapies have not been fully established. Concurrent use of these agents with TYSABRI may increase the risk of infections, including opportunistic infections, and is contraindicated (see section 4.3).
Patients with a treatment history of immunosuppressant medications are at increased risk for PML. Care should be taken with patients who have previously received immunosuppressants to allow sufficient time for immune function recovery to occur. Physicians must eva luate each individual case to determine whether there is evidence of an immunocompromised state prior to commencing treatment with TYSABRI (see section 4.3).
In Phase 3 MS clinical trials, concomitant treatment of relapses with a short course of corticosteroids was not associated with an increased rate of infection. Short courses of corticosteroids can be used in combination with TYSABRI.
Immunogenicity
Disease exacerbations or infusion related events may indicate the development of antibodies against natalizumab. In these cases the presence of antibodies should be eva luated and if these remain positive in a confirmatory test after 6 weeks, treatment should be discontinued, as persistent antibodies are associated with a substantial decrease in efficacy of TYSABRI and an increased incidence of hypersensitivity reactions (see section 4.8).
Since patients who have received an initial short exposure to TYSABRI and then had an extended period without treatment are more at risk for hypersensitivity upon redosing, the presence of antibodies should be eva luated and if these remain positive in a confirmatory test after 6 weeks treatment should not be resumed.
Hepatic Events
Spontaneous serious adverse reactions of liver injury have been reported during the post marketing phase. These liver injuries may occur at any time during treatment, even after the first dose. In some instances, the reaction reoccurred when TYSABRI was reintroduced. Some patients with a past medical history of an abnormal liver test have experienced an exacerbation of abnormal liver test while on TYSABRI. Patients should be monitored as appropriate for impaired liver function, and be instructed to contact their physician in case signs and symptoms suggestive of liver injury occur, such as jaundice and vomiting. In cases of significant liver injury TYSABRI should be discontinued.
Stopping TYSABRI therapy
If a decision is made to stop treatment with natalizumab, the physician needs to be aware that natalizumab remains in the blood, and has pharmacodynamic effects (e.g increased lymphocyte counts) for approximately 12 weeks following the last dose. Starting other therapies during this interval will result in a concomitant exposure to natalizumab. For medicinal products such as interferon and glatiramer acetate, concomitant exposure of this duration was not associated with safety risks in clinical trials. No data are available in MS patients regarding concomitant exposure with immunosuppressant medication. Use of these medicinal products soon after the discontinuation of natalizumab may lead to an additive immunosuppressive effect. This should be carefully considered on a case-by-case basis, and a wash-out period of natalizumab might be appropriate. Short courses of steroids used to treat relapses were not associated with increased infections in clinical trials.
Sodium content in TYSABRI
TYSABRI contains 2.3 mmol (or 52 mg) sodium per vial of medicinal product. When diluted in 100 ml sodium chloride 9 mg/ml (0.9%) this medicinal product contains 17.7 mmol (or 406 mg) sodium per dose. To be taken into consideration by patients on a controlled sodium diet.
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