Clinicians should monitor liver function in blood cancer patients who are taking ibrutinib (Imbruvica), the TGA has advised.

According to information published in the latest Medicines Safety Update therapy should be withheld if ≥ Grade 3 elevations in liver function tests occur – with or without a rise in bilirubin.

However once elevations decrease to Grade 1 or baseline, ibrutinib can be reinitiated at the starting dose. If toxicities persist or recur after two dose reductions ibrutinib should be discontinued.

The advice comes after several isolated post-marketing case reports of severe hepatotoxicity. The time to onset varied between five days to three months after starting treatment. Events were very rare (< 1/10,000) and in most cases were resolved after dose modification.