Imbruvica filed as first-line leukaemia therapy

Janssen and Pharmacyclics have filed an application in the US for Imbruvica as a first-line therapy for chronic lymphocytic leukaemia (CLL) which - if approved - would greatly expand the market for the drug.

Imbruvica (ibrutinib) is already on course to become a $1bn product this year in its current indications of second-line therapy for CLL and mantle cell lymphoma (MCL) and the treatment of Waldenström's macroglobulinaemia.

The drug still has a long way to go however to meet its $10bn-plus peak sales target - and also justify AbbVie's $21bn purchase of Pharmacyclics earlier this year - and first-line use in CLL is seen as critical to that objective as this is the largest patient population and treatment lasts for much longer.

AbbVie chief executive Richard Gonzalez said recently the RESONATE-2 results and shifting of Imbruvica into first-line use was "a significant portion of our valuation for Pharmacyclics," accounting for around 30% of the drug's anticipated use.

Imbruvica is a first-in-class Bruton's tyrosine kinase (BTK) inhibitor - licensed by Janssen from Pharmacyclics in 2011 in a deal valued at up to $975m. AbbVie has said it expects the drug to add $7bn to sales at peak, with first-line CLL and other B-cell cancers such as multiple myeloma all playing their part.

The FDA filing is based on the results of the late-stage RESONATE-2 trial comparing Imbruvica monotherapy to chemotherapy with chlorambucil in patients aged 65 or older with previously-untreated CLL. The results showed that treatment with J&J and Pharmacyclics' drug improved both progression-free survival (PFS) and overall survival (OS).

"Treatment-naïve patients with this disease typically relapse or become refractory to standard chemotherapy, so new options are greatly," said RESONATE-2's lead investigator Jan Burger of the University of Texas MD Anderson Cancer Center.

CLL is a slow-progressing cancer of the bone marrow and blood and is the most common leukaemia diagnosed in adults in western countries, with around 14,600 cases diagnosed in the US each year.

Imbruvica is one of a number of new therapies for CLL reaching or near the market, with others including Gilead Sciences' Zydelig (idelalisib) and AbbVie/Roche's soon-to-be-filed BCL-2 inhibitor venetoclax.