Summary Safety Review - TYSABRI (natalizumab) - Assessing the Potential Risk of Hemolytic Anemia

June 6, 2016

Product

Tysabri (natalizumab)

Potential Safety Issue

Hemolytic anemia

Key Messages

  • Tysabri (natalizumab) is used to treat patients with the relapsing-remitting form of multiple sclerosis (MS).
  • This safety review was triggered by a safety signal from a foreign regulator and published reports from the literature.
  • Health Canada’s review concluded that the evidence was too limited to confirm an increased risk of the hemolytic type of anemia in MS patients treated with Tysabri. However, post-market cases suggest that anemia is a potential consequence of Tysabri treatment. Following the completion of the safety review, the manufacturer has updated the prescribing information for Tysabri to better reflect the risk of anemia.

Overview

Health Canada carried out a safety review to assess the potential risk of hemolytic anemia with the use of Tysabri. This issue was triggered by safety information from a foreign regulator and published literature cases.

Anemia is a condition in which the body does not have enough healthy red blood cells.  In hemolytic anemia, red blood cells are destroyed and removed from the bloodstream before their normal lifespan is over.

Use in Canada

  • Tysabri is used for the treatment of patients with the relapsing-remitting form of MS. It is generally recommended for MS patients who have not responded well to other treatments or who are unable to tolerate them.
  • Tysabri is a unique immune system protein, which prevents the active immune cells from reaching the brain. It is used for decreasing the inflammation in the brain and therefore reduces nerve damage caused by MS.
  • Tysabri has been marketed in Canada since November 2006.
  • Tysabri is administered into a vein (intravenously) over time (an infusion) by a healthcare professional. The recommended dose of Tysabri is 300 mg every 4 weeks.

Safety Review Findings

  • This safety review considered Canadian and international post-market cases of anemia that were reported on MS patients treated with Tysabri. Most case reports lacked detailed information, including information to determine if the cases of anemia were of the hemolytic type.
  • The published articles reviewed cases that reported possible hemolytic anemia and anemia.
  • Overall, the evidence was too limited to support a direct link between the use of Tysabri and the risk of hemolytic anemia. However, post-market cases of anemia which were mainly “characterised by temporary decreases in hemoglobin levels”, were reported in MS patients treated with Tysabri for which a possible role of the drug could not be ruled out.
  • Anemia is a rare but potentially serious side effect in MS treatment. It is therefore important to monitor anemia during treatment with Tysabri.

Conclusions and Actions

  • Health Canada’s review concluded that there is currently insufficient evidence to support a direct link between the use of Tysabri and hemolytic anemia. However, post-market cases of anemia in MS patients treated with Tysabri were reported.
  • Health Canada requested that the manufacturer update the prescribing information to better reflect the risk of anemia.
  • Following the completion of this safety review, the manufacturer has updated the Canadian Product Monograph for Tysabri with new information about the risk of anemia.
  • Health Canada will continue to monitor side effect information involving Tysabri, as it does for all health products on the Canadian market, to identify and assess potential harms. Health Canada will take appropriate and timely action if and when any new health risks are identified.

Additional Information

The analysis that contributed to this safety review included scientific and medical literature, Canadian and international adverse reaction reports and what is known about the use of this drug both in Canada and internationally.

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