MEI Pharma, Inc. and Kyowa Kirin Co., Ltd. announced that after receiving the most recent guidance from a late November meeting with the U.S. Food and Drug Administration (FDA), the companies are discontinuing global development of zandelisib outside of Japan for B-cell malignancies. Kyowa Kirin is continuing the ongoing clinical trials including Phase 2 MIRAGE study evaluating Japanese patients with relapsed or refractory indolent B-cell non-Hodgkin lymphomas and will explore the potential for a submission to Japanese health authorities based on data from the MIRAGE and TIDAL clinical trials. In March 2022, MEI Pharma and Kyowa Kirin reported the outcome of an end of Phase 2 meeting with the FDA wherein the agency discouraged a filing based on the single-arm Phase 2 TIDAL trial evaluating zandelisib in patients with relapsed or refractory follicular lymphoma.

At this meeting, the FDA stated that a randomized trial should be used to support an initial zandelisib registration in patients with indolent non-Hodgkin lymphoma and, accordingly, data generated from single arm studies such as the Phase 2 TIDAL trial are insufficient to adequately assess the risk/benefit of PI3K inhibitors evaluating indolent non-Hodgkin lymphoma. At that time the FDA emphasized that the companies continue efforts with the ongoing randomized Phase 3 COASTAL trial evaluating patients with relapsed or refractory follicular or marginal zone lymphomas. Subsequently, at an April 2022 meeting of the FDA Oncology Drugs Advisory Committee, the committee voted that future approvals of PI3K inhibitors for hematologic malignancies should be supported by randomized data.

In late November 2022, MEI Pharma and Kyowa Kirin met with the FDA in a follow-up meeting to the March 2022 end of Phase 2 meeting. At this meeting, FDA provided further guidance regarding the design and statistical analysis for the COASTAL trial. Following the November meeting, the companies concluded that a clinical trial consistent with the recent FDA guidance, including modification of the COASTAL trial, would likely not be feasible to complete within a time period that would support further investment.

As a result, global development of zandelisib for indolent forms of non-Hodgkin lymphoma, except for Japan, is being discontinued. The discontinuation of zandelisib development outside of Japan is a business decision based on the most recent regulatory guidance from the FDA and is not related to the zandelisib clinical data generated to date. Kyowa Kirin is continuing the ongoing clinical trials including Phase 2 MIRAGE trial evaluating Japanese patients with relapsed or refractory indolent B-cell non-Hodgkin lymphomas and will explore submitting the MIRAGE and TIDAL trials for marketing authorization in Japan.

MIRAGE is a Phase 2 trial, similar in design to the global Phase 2, single-arm, TIDAL trial. In November 2022Kyowa Kirin and MEI announced positive topline data from the Phase 2 MIRAGE trial. MEI and Kyowa Kirin plan to immediately start winding-down ongoing clinical studies outside of Japan, including the Phase 3 COASTAL trial and the Phase 2 CORAL trial evaluating patients with relapsed or refractory chronic lymphocytic leukemia.

Depending on the achievement of certain regulatory and commercial milestones in Japan, MEI may be eligible for additional payments from Kyowa Kirin under the current agreement. MEI may also be entitled to royalties on any sales of zandelisib in Japan.