Imbruvica gains approval in CLL
Janssen-Cilag’s Imbruvica has gained US approval for use in chronic lymphocytic leukaemia patients who have received at least one prior therapy.
The approval signals an intensifying in the market for chronic lymphocytic leukaemia (CLL) treatments – Roche, Gilead and GSK all have new rival drugs set to battle it out for a share of the market.
Imbruvica (ibrutinib) gained its first approval in November 2013 for the treatment of mantle cell lymphoma (MCL), and is one of the first to be approved through the FDA’s ‘Breakthrough Therapy Designation’ which fast-tracks potentially groundbreaking drugs.
This means that the drug is in the unusual position of not yet having proven its efficacy in improving survival or disease-related symptoms in either of these conditions. Instead, the FDA has accepted interim results which show a very promising overall response rate (ORR) in both of these groups of patients.
Jointly developed and commercialised by Janssen (J&J’s pharma division) and Pharmacyclics, Imbruvica is a once-daily oral agent and works by inhibiting Bruton’s tyrosine kinase (BTK). This plays an important role in B-cell receptor signalling, which helps spreading B-cell malignancies such as CLL.
The current standard treatment for CLL is chemotherapy plus Roche’s Rituxan/MabThera (rituximab), but patients develop a resistance to the drug, and doctors need new treatment options.
Roche has a second-generation version of rituximab already approved – Gazyva (obinutuzumab) which gained FDA approval to treat CLL in November. The drug showed superior results to Rituxan when combined with chemotherapy in helping patients to live longer without their disease progressing, putting it in a very strong position in the market.
Imbruvica’s other big rival is Gilead’s idelalisib. Phase 3 trial data showed that in combination with Rituxan, it scored a 93% progression-free survival rate at 24 weeks, roughly double the results for rituximab alone.
Meanwhile GSK and Genmab’s Arzerra is also waiting in the wings. The drug was first approved in 2009, but has now been designated a received Breakthrough Therapy as well. It could gain approval for use in patients earlier in the disease cycle.
Analysts predict Imbruvica can hit peak sales of between $4billion and 6.5 billion, as long as it continues to add new indications.
Because of Gilead’s decision to combine idelalisib with rituximab, analysts think that doctors may prefer this add-on approach when patients start to show resistance to rituximab. However if Imbruvica can demonstrate compelling data, physicians may favour it over its rival.
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