Celgene Corp has warned doctors in the UK that its newly approved blood cancer drug Imnovid can cause life-threatening birth defects.

In a letter to healthcare professionals, the drugmaker stressed that the medicine is structurally related to thalidomide, a known human teratogen that causes severe life-threatening birth defects.

Because of a similar effect observed in rabbits and rats, taking Imnovid (pomalidomide) during pregnancy is also expected to have a tetratogenic effect in humans, it said.

The drug recently received a green light in Europe in combination with dexamethasone to treat adult patients with relapsed and refractory multiple myeloma (MM) who have received at least two prior treatment regimens, and have demonstrated disease progression on the last therapy.

While the disease predominantly occurs in the elderly, women of child-bearing age could be part of the patient population, and so must be counselled on the risks and also promise to use an effective method of contraception for before, during and after therapy or completely abstain from sex.

It is also required that several medically-supervised pregnancy tests are undertaken at various points in the pre- and post-treatment pathway, Celgene said.

As the drug is also present in semen, male patients should use condoms throughout treatment duration, during dose interruption and for one week after cessation of treatment if their partner is pregnant or of childbearing potential and not using effective contraception.