A pivotal trial of Gilead Sciences’ idelalisib in patients with chronic lymphocytic leukaemia (CLL) is to be stopped after preliminary results indicated the drug provides significant benefit.
The trial – known as Study 116 – is comparing idelalisib plus Roche/Biogen Idec’s Rituxan (rituximab) to rituximab alone in patients unsuitable for treatment with conventional chemotherapy.
At an interim analysis, the combination was found to have a clear and significant advantage in terms of progression-free survival (PFS) compared to monotherapy with rituximab – which is already approved for CLL therapy – making a case that patients should be swapped to the combination treatment.
Gilead said the findings mean it can now approach the FDA with a view to establishing whether the data will be robust enough to move ahead with a filing in CLL, which could raise the possibility of approval in 2014.
CLL is a slow progressing but hard-to-treat blood cancer generally affecting older people, and is seen as a major growth market within haematology that could be worth as much as $10bn a year.
Idelalisib is one of a new batch of B cell targeting drugs that promise to provide another line of treatment for CLL therapies, along with other advantages over existing therapies such as oral administration.
The compound works by inhibiting phosphatidylinositide 3-kinase (PI3K), a cellular pathway involved in cell growth and proliferation which is known to be hyperactive in CLL.
Idelalisib is thought to be the furthest along in development among the PI3K inhibitor class – it was submitted for approval in the US as a treatment for non-Hodgkin’s lymphoma last month – although another candidate from Infinity Pharmaceuticals’ called IPI145 has shown early promise in phase I dose-ranging studies and is now in phase II.
Meanwhile, another B cell-targeting drug with a slightly different mode of action – Johnson & Johnson’s ibrutinib – has also shown promise in trials and could be available around the turn of the year, having been filed for approval in the US in July.
Ibrutinib is a Bruton’s tyrosine kinase (BTK) inhibitor licensed by J&J from Pharmacyclics and has been granted breakthrough status by the FDA.
“This is the first phase III study to report positive results for a new class of targeted therapies that inhibit B-cell receptor signaling as a major component of their mechanism of action,” commented Gilead’s R&D head Norbert Bischofberger.
“We look forward to sharing these data with the haematology community,” he added.