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NEW YORK, Dec. 17, 2018 (GLOBE NEWSWIRE) -- TG Therapeutics, Inc. (NASDAQ: TGTX) and Dana-Farber Cancer Institute today announced the publication of results from the multicenter Phase 1/1b trial of umbralisib (TGR-1202), TG Therapeutics’ novel once-daily PI3K delta inhibitor, in combination with ibrutinib, the oral Bruton's tyrosine kinase (BTK) inhibitor, in Lancet Haematology. This investigator-initiated trial was conducted at Dana-Farber Cancer Institute and four additional academic and community sites across the USA in collaboration with the Leukemia and Lymphoma Society Blood Cancer Research Partnership with funding by TG Therapeutics. The publication includes safety and efficacy information from a total of 42 relapsed or refractory patients, 21 with chronic lymphocytic leukemia (CLL) and 21 with mantle cell lymphoma (MCL).  

In this study, the combination of umbralisib and ibrutinib was well tolerated and consistent with the additive toxicity profile of the two drugs individually. No dose-limiting toxicities were observed, and the maximum-tolerated dose of umbralisib when combined with ibrutinib was not reached. The recommended phase 2 dose of umbralisib when given in combination with ibrutinib was 800 mg once daily. Importantly, serious immune-mediated toxicities were not observed with this combination, as had previously been reported with combinations of different agents targeting this pathway, with only one case of transient Grade 3 transaminitis and no Grade 3/4 colitis or pneumonitis. The combination of umbralisib and ibrutinib was also clinically active, with 90% of relapsed/refractory CLL patients achieving an overall response (n=19), of which 62% (n=13) achieved a partial response or partial response with lymphocytosis, and 29% (n=6) achieved a complete response. Of the 21 patients treated with MCL, 67% (n=14) achieved an overall response, of which 48% (n=10) achieved a partial response and 19% (n=4) achieved a complete response. 

These data are described further in the manuscript entitled, “Umbralisib in combination with ibrutinib in patients with relapsed or refractory chronic lymphocytic leukaemia or mantle cell lymphoma: a multicenter phase 1–1b study,” which was published today in Lancet Haematology. The online version of the article can be accessed at http://www.thelancet.com/journals/lanhae/article/PIIS2352-3026(18)30196-0/fulltext.

“Our study demonstrates for the first time that it is feasible to combine two agents targeting B cell receptor pathway kinases in patients with B cell malignancies,” said Matthew Davids, MD, MMSc, Associate Director of the Center for Chronic Lymphocytic Leukemia at Dana-Farber. Dr. Davids continued, “We are particularly encouraged by the depth of response in the CLL patients, which compares favorably to historical data for ibrutinib monotherapy in this relapsed population. Our data support further exploration of dual BCR pathway blockade in CLL and other B cell malignancies.”

Michael S. Weiss, the Company's Executive Chairman and Chief Executive Officer, stated “We want to thank Dr. Davids and the team at Dana-Farber, and most importantly the patients who participated in this trial. We are excited to publish the first ever data evaluating the all oral combination of a PI3K delta inhibitor with a BTK inhibitor and believe this paper further highlights the favorable safety profile and combinability of umbralisib as compared to prior generation PI3k deltas. We believe these data support our plans to develop combinations utilizing umbralisib plus our BTK inhibitor, TG-1701, which has already demonstrated activity in patients in early clinical studies.”

ABOUT TG THERAPEUTICS, INC.

TG Therapeutics is a biopharmaceutical company focused on the acquisition, development and commercialization of novel treatments for B-cell malignancies and autoimmune diseases. Currently, the company is developing two therapies targeting hematological malignancies and autoimmune diseases. Ublituximab (TG-1101) is a novel, glycoengineered monoclonal antibody that targets a specific and unique epitope on the CD20 antigen found on mature B-lymphocytes. TG Therapeutics is also developing umbralisib (TGR-1202), an orally available PI3K delta inhibitor. The delta isoform of PI3K is strongly expressed in cells of hematopoietic origin and is believed to be important in the proliferation and survival of B‐lymphocytes. Both ublituximab and umbralisib, or the combination of which is referred to as "U2", are in Phase 3 clinical development for patients with hematologic malignancies, with ublituximab also in Phase 3 clinical development for Multiple Sclerosis. Additionally, the Company has recently brought its anti-PD-L1 monoclonal antibody, TG-1501, as well as its covalently-bound Bruton Tyrosine Kinase (BTK) inhibitor, TG-1701, into Phase 1 development and aims to bring additional pipeline assets into the clinic in the future. TG Therapeutics is headquartered in New York City.

Cautionary Statement

Some of the statements included in this press release may be forward-looking statements that involve a number of risks and uncertainties.  For those statements, we claim the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.  In addition to the risk factors identified from time to time in our reports filed with the Securities and Exchange Commission, factors that could cause our actual results to differ materially are the following: our ability to successfully and cost effectively complete preclinical and clinical trials; the risk that early preclinical and clinical trial results, that may have supported the acceptance of our data for publication or influenced our decision to proceed with additional clinical trials, will not be reproduced in future studies or in future data presentations; the risk that umbralisib will not maintain its differentiated safety profile as patients continue to be treated on drug for longer durations and more patients are enrolled; the risk that the combination of ublituximab (TG-1101) and umbralisib (TGR-1202), referred to as U2 and being studied in the UNITY clinical trials, will not prove to be a safe and efficacious combination, or backbone for triple therapy combinations; the risk that we will not commence clinical trials of umbralisib plus TG-1701 or of U2 plus TG-1701; the risk that the early data seen with TG-1701 will not b reproduced in future trials. Any forward-looking statements set forth in this press release speak only as of the date of this press release. We do not undertake to update any of these forward-looking statements to reflect events or circumstances that occur after the date hereof. This press release and prior releases are available at www.tgtherapeutics.com. The information found on our website is not incorporated by reference into this press release and is included for reference purposes only.

CONTACT:

Jenna Bosco
Senior Vice President,
Corporate Communications
TG Therapeutics, Inc.
Telephone: 212.554.4351
Email: ir@tgtxinc.com

Source: TG Therapeutics, Inc.