On April 1, 2019 TG Therapeutics, Inc. (NASDAQ: TGTX) reported positive interim data from the ongoing single-arm marginal zone lymphoma (MZL) cohort of its Phase 2b clinical trial known as UNITY-NHL (Press release, TG Therapeutics, APR 1, 2019, View Source [SID1234534821]). The MZL cohort of UNITY-NHL is designed to investigate umbralisib as a single agent in patients with relapsed or refractory MZL. Umbralisib is an investigational, oral, once daily PI3K delta inhibitor with unique inhibition of CK1 epsilon and is currently under development for the treatment of non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL).
The interim data were reported this morning by Dr. Nathan Fowler, Associate Professor of Medicine and Director of Clinical Research in the Department of Lymphoma/Myeloma at the University of Texas MD Anderson Cancer Center and Study Chair of the UNITY-NHL MZL cohort, during this morning’s official 2019 Press Program at the American Association of Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting. Dr. Fowler will also present the data during an oral session this afternoon (details below).
Summary of Data Presented:
The MZL cohort of UNITY-NHL enrolled patients with relapsed or refractory MZL who had received prior treatment with one or more lines of therapy including at least one anti-CD20 regimen. In August 2018, the trial completed enrollment with 69 treated patients. The interim data reported today included safety and tolerability data on all 69 treated patients (safety population) and efficacy data on 42 patients who were enrolled at least 9 cycles (28 day cycles) prior to the data cut-off date (interim efficacy population). The primary endpoint is overall response rate (ORR) as assessed by IRC using criteria adopted from the International Working Group criteria for malignant lymphoma.
Efficacy
Analysis of the interim efficacy population (n=42) with a median follow-up of 12.5 months showed the following:
Interim Efficacy Population (n=42)
Overall Response Rate by IRC (CR + PR), %
52%
Complete Response by IRC (CR), (%)
19%
Partial Response by IRC (PR), (%)
33%
Median duration of response, months
NR (95% CI: 8.4 – NE)
CI = confidence interval; NR = not reached; NE = not estimable; SD = stable disease
Additional Efficacy Highlights:
● 88% clinical benefit rate by IRC (defined as patients obtaining Complete Response + Partial Response + Stable Disease)
● All patients achieving a Complete Response by IRC remain on study (range: 10.1+ to 15.7+ months)
● 86% of patients had a reduction in tumor burden
● Median time to initial response was 2.7 months
● Kaplan-Meier (KM) estimate of progression-free survival (PFS) at 12 months was 66%, with the median PFS not reached
Safety
Interim safety data were presented for all 69 treated patients with a median duration of exposure of 6.9 months. No unexpected toxicities were observed. The most common adverse events were diarrhea, nausea, and fatigue, with the majority of events Grade 1 in severity. The most frequent grade 3 or higher adverse events were neutropenia, diarrhea and ALT/AST increase, observed in 13%, 10% and 10% of patients, respectively.
A subgroup analysis of patients treated for greater than 6 cycles (n=41) was also conducted to evaluate long-term incidence of key toxicities of interest occurring after 6 cycles of treatment. Median duration of treatment of this subgroup was 10.1 months (range: 5.6 – 19.1 months). In this subgroup, grade 3 or higher adverse events of interest were rare, limited to 2 patients with diarrhea and 1 patient with pneumonitis, with no events of ALT/AST elevation, pneumonia, or colitis.
Key Safety Findings (n=69):
● No events of colitis were reported and only 1 event of Grade 3 pneumonitis was reported
● Grade 3 infections were limited, occurring in 3 patients (bronchitis, pneumonia, and influenza)
● Discontinuations due to umbralisib-related AEs were limited (14%) with no discontinuations after 6 months due to a treatment-related AE
● No deaths occurred on study
Dr. Nathan Fowler, Associate Professor of Medicine and Director of Clinical Research in the Department of Lymphoma/Myeloma at The University of Texas MD Anderson Cancer Center and the Study Chair of the UNITY-NHL MZL cohort, stated, "MZL remains an incurable disease with few treatment options for patients who relapse after first-line chemoimmunotherapy. The exciting results presented today suggest that this oral targeted therapeutic has significant activity against relapsed/refractory marginal zone lymphoma and offers hope for patients." Dr. Fowler continued, "The adverse event and clinical activity data are highly encouraging at this point and we are excited to continue following patients for a longer time. With the results reported thus far, umbralisib has the potential to make a real difference for patients with relapsed/refractory marginal zone lymphoma."
Michael S. Weiss, Executive Chairman and Chief Executive Officer of TG Therapeutics stated, "We are very excited about these interim data and believe the results today demonstrate the activity and differentiated safety and tolerability profile of umbralisib at our Phase 3 dose of 800 mg once per day." Mr. Weiss continued, "As announced previously, the efficacy for the entire population has already reached our target range of 40-50% ORR and we look forward to presenting the final data from the entire MZL cohort later this year when all patients have had the opportunity to be followed for at least 9 cycles. In addition, we look forward to discussing the results with the FDA with a goal of filing for accelerated approval by year end."
CONFERENCE CALL INFORMATION
The Company will host a conference call today, Monday April 1, 2019, at 12:00pm (noon) ET. Michael S. Weiss, Chief Executive Officer of TG Therapeutics, will host the call and Dr. Nathan Fowler, Associate Professor of Medicine and Director of Clinical Research in the Department of Lymphoma/Myeloma at The University of Texas MD Anderson Cancer Center in Houston and Study Chair of the MZL cohort, will review the UNITY-NHL interim MZL data.
In order to participate in the conference call, please call 1-877-407-8029 (U.S.), 1-201-689-8029 (outside the U.S.), Conference Title: TG Therapeutics AACR (Free AACR Whitepaper) Update Call.
A live webcast and accompanying slides will be available on the Events page, located within the Investors & Media section, of the Company’s website at View Source An audio recording of the conference call will also be available for replay at www.tgtherapeutics.com for a period of 30 days after the call.
2019 AACR (Free AACR Whitepaper) ORAL PRESENTATION DETAILS
● Title: Umbralisib monotherapy demonstrates efficacy and safety in patients with relapsed/refractory marginal zone lymphoma: A multicenter, open-label, registration directed Phase II study
o Session Date and Time: Monday April 1, 2019 3:00 PM – 5:00 PM ET
o Presentation Time: 4:20 PM ET
o Session Title: The Next Generation of Clinical Trials in Molecularly-driven Therapy
o Session Location: Marcus Auditorium- Bldg A-GWCC
o Presenter: Nathan Fowler, MD, Associate Professor, Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, TX
o Abstract Number: 7821
The full text of the abstract is now available and can be accessed via the AACR (Free AACR Whitepaper) meeting website at www.aacr.org. The slides to be presented in this afternoon’s oral presentation are available on the Company’s corporate website at www.tgtherapeutics.com/publications.cfm.
ABOUT THE UNITY-NHL PHASE 2b STUDY—Marginal Zone Lymphoma Cohort
The multicenter, open-label, UNITY-NHL Phase 2b study – Marginal Zone Lymphoma cohort was designed to evaluate the safety and efficacy of single agent umbralisib, in patients with MZL who have received at least one prior anti-CD20 regimen. The primary endpoint is overall response rate (ORR) as determined by central Independent Review Committee (IRC) assessment.
The MZL cohort completed enrollment in August 2018 with a total of 69 patients enrolled and receiving at least one dose of umbralisib. In February of 2019, the Company announced that the MZL cohort met its primary endpoint of ORR as determined by central IRC for all treated patients (n=69). While the study has already met the Company’s target guidance of 40-50% ORR, the final analysis of ORR will be conducted when all treated patients have had at least 9 cycles (cycle = 28 days) of follow-up. Secondary endpoints include safety, duration of response, and progression-free survival (PFS).
ABOUT BREAKTHROUGH THERAPY DESIGNATION
The Company announced in January of 2019 that the U. S. Food and Drug Administration (FDA) granted Breakthrough Therapy Designation for umbralisib for the treatment of adult patients with marginal zone lymphoma who have received at least one prior anti-CD20 regimen.
The FDA’s Breakthrough Therapy designation is intended to expedite the development and review of a drug candidate that is planned to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement on one or more clinically significant endpoints over available therapies.
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