Background Pegylated Interferon-alpha-2b (pegIFN_α2b) is an effective agent for the treatment of haematological malignancies. As it does not inhibit DNA synthesis, this agent may be safe for use during pregnancy.

Purpose To describe 2 cases of successful pregnancies in patients with haematological disorders treated with pegIFN_α2b.

Material and methods Medical record review and literature search.

Results Patient 1: 30-year-old woman diagnosed with polycythaemia vera at age 13, well-controlled with hydroxyurea. Chemotherapy was interrupted due to the patient’s desire for a second pregnancy and treatment with pegIFN_α2b 50mcg/week subcutaneously was initiated. (During the first pregnancy she received non-pegylated-IFN_α2b with good progression but low tolerance due to influenza-like symptoms). 5 months later, she became pregnant, but was hospitalised due to headaches which caused a dose reduction to 30 mcg/week of pegIFN_α2b. Finally, the patient delivered a healthy male infant. 15 days later, pegIFN_α2b treatment was interrupted to recommence the usual treatment with hydroxyurea.

Patient 2: 27-year-old woman with Philadelphia chromosome-positive chronic myeloid leukaemia diagnosed at age 22, well-controlled with imatinib. The patient interrupted antineoplastic treatment due to her desire to conceive a child and subcutaneous treatment with pegIFN_α2b at 50 mcg/week was initiated. She became pregnant after 4 months and pegIFN_α2b dose was increased to 80 mcg/week and developed hypothyroidism which was treated with levothyroxine. Finally, the patient delivered a healthy male infant and 1 month later, she discontinued pegIFN_α2b and levothyroxine treatment to recommence her usual treatment with imatinib.

Both were normal full-term deliveries. Infant growth and development have been normal to date (follow-up time of 2 and 3 years). Blood tests were normal during pregnancies. Only mild anaemia and slight neutrophilia were detected in the first patient, but did not require treatment interruption.

Conclusion PegIFN_α2b was well tolerated, safe and effective, and caused no complications during the pregnancies. Since chemotherapy agents involve teratogenic effects, pegIFN_α2b might be a safe treatment option during pregnancy, although further teratogenic studies are necessary.

References and/or acknowledgements No conflict of interest.