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09-07-2021 16:42 |
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EMA
finds no evidence linking viral vector in Zynteglo to blood cancer |
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EMA’s safety committee (PRAC)
has concluded that there is no evidence Zynteglo causes a blood cancer known
as acute myeloid leukaemia (AML). Zynteglo,
a gene therapy for the blood disorder beta thalassaemia, uses a viral vector
(or modified virus) to deliver a working gene into the patient’s blood
cells. The PRAC reviewed two cases of AML in patients treated with an investigational medicine, bb1111, in a clinical trial for sickle cell disease. Although there have been no reports of AML with Zynteglo, both medicines use the same viral vector and there was a concern that the vector may be implicated in the development of the cancer (insertional oncogenesis). The review
found that the viral vector was unlikely to be the cause. In one of the
patients, the viral vector was not present in the cancer cells, and in the
other patient it was present at a site (VAMP4) that does not appear to be
involved in cancer development. After
examining all the evidence, the PRAC concluded that more plausible
explanations for the AML cases included the conditioning treatment the
patients received to clear out bone marrow cells and the higher risk of blood
cancer in people with sickle cell disease. Patients
having Zynteglo treatment for beta thalassaemia also need conditioning treatment
to clear out their bone marrow cells. Healthcare professionals should
therefore explicitly inform patients receiving Zynteglo of the increased risk
of blood cancers from medicines used in conditioning treatments. The PRAC
has also updated its recommendations for monitoring patients. Healthcare
professionals should now check their patients for signs of blood cancers at least once a year
for 15 years.[1] The
Committee, which worked closely with experts from the Committee
for Advanced Therapies (CAT), concluded that the benefits of Zynteglo
continue to outweigh its risks. As for all medicines, the PRAC will monitor
any new data on its safety and update advice for patients and healthcare
professionals when necessary. More about the medicine Zynteglo
is a one-time treatment for a blood disorder known as beta thalassaemia in
patients 12 years and older who require regular blood transfusions. To make
Zynteglo, the stem cells taken from the patient’s blood are modified by a
virus that carries working copies of the beta-globin gene into the cells.
When these modified cells are given back to the patient, they are transported
in the bloodstream to the bone marrow where they start to make healthy red
blood cells that produce beta-globin. The effects of Zynteglo are expected to
last for the patient’s lifetime. Zynteglo
was granted conditional
marketing authorisation in May 2019. The conditional authorisation
means that there is more evidence to come about the medicine, which the
company will provide. EMA regularly reviews new information that becomes
available. More about the procedure The review
of Zynteglo was initiated on 18 February, 2021 at the request of the
European Commission, under Article
20 of Regulation (EC) No 726/2004. The review
was first carried out by the Pharmacovigilance Risk Assessment Committee
(PRAC), the Committee responsible for the evaluation of safety issues for
human medicines, which worked closely with experts from the Committee for
Advanced Therapies (CAT). The PRAC
recommendations will now be sent to the CAT and subsequently to the Committee
for Medicinal Products for Human Use (CHMP), responsible for questions
concerning medicines for human use, which will adopt the Agency’s opinion.
The final stage of the review procedure is the adoption by the European
Commission of a legally binding decision applicable in all EU Member States. [1]
The previous recommendation was for healthcare professionals to check for
signs of cancer once a year. (MKY) |
