MEI Pharma (MEIP) and Kyowa Kirin Reports Data From the Ongoing Global Phase 2 TIDAL Study Evaluating Zandelisib
MEI Pharma, Inc. (NASDAQ: MEIP), a late-stage pharmaceutical company focused on advancing new therapies for cancer, and Kyowa Kirin Co., Ltd., a global specialty pharmaceutical company that utilizes the latest biotechnology to discover and deliver novel medicines, today announced that the pivotal Phase 2 TIDAL study evaluating zandelisib as a single agent for follicular lymphoma (FL) patients who received at least two prior systemic therapies demonstrated a 70.3% objective response rate (ORR) as determined by Independent Review Committee (IRC) assessment in the primary efficacy population (n=91). In addition, 35.2% of patients achieved a complete response. The data are currently insufficiently mature to accurately estimate duration of response (DOR). In line with previously reported data from the Phase 1B study, zandelisib was generally well tolerated. With 9.4 months (range: 0.8-24) median duration of follow-up in the total study population (n=121), interim data demonstrated a discontinuation rate due to any drug related adverse event of 9.9%. Patients enrolled in the study will continue to be followed for safety and DOR. Zandelisib is an investigational selective phosphatidylinositol 3-kinase delta ("PI3Kδ") inhibitor in clinical development for the treatment of B-cell malignancies.
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Overview of Preliminary TIDAL Data in Relapsed or Refractory (r/r) FL
The ongoing TIDAL study (NCT03768505) is a global, open-label Phase 2 trial evaluating zandelisib as a single agent across two disease cohorts: the first cohort for the treatment of adults with r/r FL and the second cohort for r/r marginal zone lymphoma (MZL), in both cases after failure of at least two prior systemic therapies, including chemotherapy and an anti-CD20 antibody. Enrollment in the FL cohort is complete; enrollment in the MZL cohort is ongoing. Subject to the results and discussion with the U.S. Food and Drug Administration (FDA), TIDAL study data from each study cohort are intended to be submitted to the FDA to support accelerated approval marketing applications.
The r/r FL cohort enrolled a total of 121 patients, 91 of which were enrolled in the primary efficacy population for the evaluation of ORR and DOR. The median age of patients with FL was 64 years old. Patients enrolled in both the FL primary efficacy and total patient populations received a median of 3 prior lines of treatment (range: 2-8). Patients were administered zandelisib once daily for two 28-day cycles as response induction therapy, followed thereafter by once daily dosing for the first seven days of each subsequent 28-day cycle, a schedule called Intermittent Dosing Therapy (IDT).
Efficacy
The ORR in the 91 patients with r/r FL enrolled in the primary efficacy population was 70.3% (n=64), 95% CI=59.8, 79.5, as assessed by IRC after a minimum follow-up of 6 months; the complete response rate was 35.2%, 95% CI=25.4, 45.9. The ORR represents the primary endpoint of the TIDAL study.
As of the data cutoff date, the data are not sufficiently mature to accurately estimate the final DOR in the FL primary efficacy population, a secondary outcome measure of the TIDAL study. However, with a median follow-up time for response of 8.4 months, the median DOR had not been reached. The data cutoff date is approximately 6 months after the last patient in the primary efficacy population received their first dose of zandelisib.
Safety and Tolerability
Zandelisib appeared generally well-tolerated in the total TIDAL study population through the data cutoff date. The safety observed in TIDAL was consistent with data previously reported from the Phase 1B study (NCT02914938) evaluating zandelisib in patients with B-cell malignancies as a single agent or in combination with rituximab (Rituxan®).
As of the data cutoff date, with a median follow up of 9.4 months (range: 0.8-24) in the total FL study population, the incidence of Grade ≥3 Adverse Events of Special Interest were: 1.7% ALT/AST elevation, 1.7% colitis, 5% diarrhea, 2.5% mucositis, 0.8% pneumonitis, and 3.3% rash. The discontinuation rate due to any drug related adverse event in the group was 9.9%, also as of the data cutoff date.
A more complete report of the TIDAL data as of the data cutoff date will be submitted for presentation at upcoming scientific congresses in 2022.
“The emerging zandelisib data are very promising and indicate the potential to positively impact the standard-of-care for patients with relapsed or refractory follicular lymphoma,” said Daniel P. Gold, Ph.D., president and chief executive officer of MEI Pharma. “The response data and interim safety data reported today support our plans to continue discussions with the FDA on timing of an accelerated approval submission, and we look forward to reporting a more comprehensive review of the data at upcoming medical conferences while continuing this trial and continuing to advance the zandelisib clinical development program in indications beyond follicular and marginal zone lymphomas with our partner, Kyowa Kirin.”
“We are encouraged by the zandelisib data reported today from the TIDAL study,” said Yoshifumi Torii, PhD, Executive Officer, vice president, Head of R&D Division of Kyowa Kirin. “Our team is continuing to study this investigational medicine with our partner MEI Pharma in the hopes of understanding zandelisib’s value and bringing more hope to lymphoma patients around the world.”
MEI Pharma Conference Call and Webcast
MEI will host an investor and analyst webcast event today, November 30, 2021, at 8:00 AM Eastern Time to review the TIDAL phase 2 study data reported today and to provide a corporate overview.
You can access the live webcast with slides under the investor relations section of MEI's website on the "Events and Presentation" page at: www.meipharma.com. A replay of the webcast will be archived for at least 30 days after the conclusion of the live event.
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