European regulators have cleared Pfizer’s Mylotarg to treat a certain subset of patients with acute myeloid leukaemia (AML).

The approval allows doctors to prescribe the drug in combination with daunorubicin and cytarabine for patients aged 15 years and above with previously untreated, de novo, CD33-positive acute myeloid AML, except acute promyelocytic leukaemia (APL).

Mylotarg (gemtuzumab ozogamicin) is a targeted therapy that consists of an antibody connected to an anti-tumor agent that is toxic to cells, thought to work by taking the anti-tumour agent to the AML cells that express the CD33 antigen, blocking the growth of cancerous cells and causing cell death.

The decision gives patients the potential to access a new treatment option for their disease, as the drug is the first and only AML therapy approved in the EU that targets CD33, an antigen expressed on AML cells in up to 90 percent of patients.

“In clinical trials, the addition of gemtuzumab ozogamicin to standard chemotherapy resulted in more durable remission, thus providing an additional treatment option with the potential to prevent relapse for these patients,” noted Andreas Penk, regional president, Pfizer Oncology.

In one trial, patients who received Mylotarg survived longer than those who received only best supportive care, with median overall survival 4.9 months versus 3.6 months. Data from another showed that following treatment with the drug, 26 percent of patients achieved a complete remission that lasted a median 11.6 months.

AML is a rapidly progressing, life-threatening blood and bone marrow cancer, which, if left untreated, can be fatal within weeks or months.

Every year, around 2,600 people in the UK are affected by the condition, with around 16,800 new cases diagnosed across Europe.