Gilead Sciences ($GILD) is sprinting toward FDA approval with the promising idelalisib, a targeted cancer therapy that met all its Phase III endpoints, giving the company another boost in the competitive landscape for chronic lymphocytic leukemia (CLL) treatments.
In late-stage data, idelalisib paired with Rituxan scored a 93% progression-free survival rate at 24 weeks, roughly double the results for Roche's ($RHHBY) old drug alone. The drug's overall response rate came in at 81%, besting Rituxan's 13% and making clear why Gilead's data monitoring committee gave it the go-ahead to end its CLL study early. Gilead plans to present its results at December's American Society of Hematology meeting.
Those data set up idelalisib for a head-to-head with Johnson & Johnson ($JNJ) and Pharmacyclics' ($PCYC) Imbruvica, assuming both win expected approvals for CLL in the near term, Leerink Swann's Howard Liang wrote in a note to investors. Liang figures doctors will consider the drugs to be essentially equal in efficacy but gives Imbruvica an edge largely because of its higher profile.
"However, it remains to be seen whether the awareness gap narrows as a result of the upcoming ASH," Liang wrote. "Given the impressive Phase III Study 116 data, idelalisib may gain rapid awareness."
Meanwhile, Roche's Rituxan successor, Gazyva, won FDA approval to treat CLL earlier this month on the merits of strong overall survival results.
Gilead's drug, picked up in the company's $600 million deal for Calistoga, works by blocking overactive PI3K-delta signaling, cutting off a key contributor to cancer growth in B-cell leukemias and lymphomas. Idelalisib, like Imbruvica and Gazyva, won the FDA's breakthrough designation, and the agency is already reviewing the drug for non-Hodgkin's lymphoma.
- read Gilead's statement
- here's the study abstract