Gilead Sciences' Kite Pharma has filed for FDA approval of its second CAR-T cell therapy. Kite hopes to win approval for KTE-X19 in mantle cell lymphoma (MCL) on the strength of midphase results linking it to a 67% complete response rate.
KTE-X19, like Yescarta, is an anti-CD19 CAR-T therapy. The difference stems from the manufacturing process, which in the case of KTE-X19 features T-cell selection and lymphocyte enrichment. Through the lymphocyte enrichment process, Kite thinks it can make CAR-T therapies suitable for use in B-cell malignancies with circulating lymphoblasts.
Recently presented phase 2 data added weight to that hypothesis, positioning Kite to file for FDA approval this week. As a breakthrough-designated therapy, KTE-X19 could benefit from an expedited review by the FDA.
The review will go over phase 2 results Kite shared at the American Society of Hematology (ASH) annual meeting. At ASH, Kite revealed 67% of the 60 patients treated with KTE-X19 in a phase 2 trial had a complete response. The objective response rate came in at 93%, suggesting KTE-X19 works in a heavily pretreated population.
Kite also shared data on the durability of the responses. More than half of patients had an ongoing response at the cutoff, which featured a median follow-up of 12.3 months. In the subset of patients with at least 24 months of follow-up, 43% stayed in remission without additional therapy.
The data suggest KTE-X19 can find a role in the MCL treatment pathway. Use of BTK inhibitors such as Imbruvica has improved response rates in MCL patients in recent years, but the prognosis for people who progress after treatment with these drugs is poor. All the participants in Kite’s trial had received a BTK inhibitor, plus an average of two other therapies, prior to treatment with KTE-X19.
Winning FDA approval could provide a boost to Gilead’s cell therapy business, which is yet to deliver the sales to justify the $11.9 billion takeover of Kite. Sales of Yescarta, Kite’s sole approved therapy, fell slightly in the third quarter to $118 million.