Gilead Sciences has consolidated its expansion into oncology with EU approval for Zydelig, its drug for two rare and incurable B-cell cancers.
Zydelig (idelalisib) has been approved by the European Commission for use in the treatment of patients with chronic lymphocytic leukaemia (CLL) and follicular lymphoma (FL).
The new, orally-active drug can also be used alongside Roche’s MabThera/Rituxan (rituximab) as a second-line treatment for CLL patients and also as a first-line therapy for patients with a specific genetic mutation (17p deletion or TP53 mutation).
In the case of FL, the drug can be used as a monotherapy in patients who are refractory to two prior lines of treatment, according to Gilead. The drug is an inhibitor of PI3K delta, a protein over-expressed in many B-cell malignancies.
Peter Hillmen of Leeds Teaching Hospitals NHS Trust in the UK, said: “Although chemo-immunotherapy is initially used to treat both CLL and FL, relapse is common and many patients run out of treatment options to treat the disease as it progresses.”
“Zydelig is a welcomed treatment option that offers a new approach in the management of these cancers,” he added.
Zydelig was approved by the US FDA for CLL and FL as well as another B-cell cancer called small lymphocytic lymphoma (SLL) in July, mounting a challenge to Johnson & Johnson and Pharmacyclics’ Imbruvica (ibrutinib) which was approved in the US in February and achieved sales of around $105m in the second quarter of this year.
In the US Gilead has priced its drug at a roughly a $1,000 discount to Imbruvica at a little over $7,000 per month, but analysts have suggested the competitive profile for Zydelig is somewhat hampered by a black box warning on its label regarding side effects such as severe diarrhoea, pneumonitis and intestinal perforation.
Zydelig could also struggle against its rival given it is indicated for use alongside MabThera/Rituxan while Imbruvica can be given as a monotherapy, which could also have cost implications. Meanwhile, both drugs are facing competition in CLL from Roche’s Gazyvaro (obinutuzumab) – approved in Europe last month – as well as AbbVie’s ABT-199 and GlaxoSmithKline/Genmab’s Arzerra (ofatumumab).
Gilead has been working to build a portfolio in oncology in recent years and expand beyond its traditional focus in infectious diseases and specifically HIV and hepatitis C.
Its aspirations in cancer hit a setback earlier this month when LOXL2 inhibitor simtuzumab failed to achieve a survival benefit in a pancreatic cancer trial, although the drug remains in development for idiopathic pulmonary fibrosis (IPF), myelofibrosis, non-alcoholic steatohepatitis (NASH) and colorectal cancer.