Certain Blood Cancer Treatments Pulled from US Market After Treatment Results Fail to Show Improved Survival


The pharmaceutical company developing a combination regimen of ublituximab plus Ukoniq (known as U2) pulled the drug duo’s indications for the treatment of multiple types of blood cancer after clinical trial results fell short of improving overall survival.

After study results showed that treatment with ublituximab plus Ukoniq (umbralisib) failed to improve overall survival compared with Gazyva (obinutuzumab) and chlorambucil, TG Therapeutics, the manufacturers of the agents, withdrew its application for the drug duo’s Biologics License Application (BLA) and supplemental New Drug Application (sNDA) for patients with chronic lymphocytic leukemia (CLL) and small lymphocytic leukemia (SLL).

A pharmaceutical company files a BLA to ask permission to introduce a new biological product into the market, while an sNDA is asking the FDA to allow a new dosage or strength of a drug that was already approved by the FDA.

The phase 3 UNITY-CLL was a global, randomized trial investigating the effects of ublituximab plus Ukoniq — a drug combination referred to as U2 —in patients with relapsed or refractory CLL that has not previously been treated.

While the trial met its main goal of improving progression-free survival (time from treatment until the disease gets worse), Gazyva and chlorambucil bested U2 when it came to overall survival.

Of note, in September 2021 when the overall survival data was collected, about 15% of patients had missing or outdated survival data, and when considering COVID-19—related deaths, the two patient groups were relatively balanced, according to a press release from TG therapeutics. Then, in February 2022, the pharmaceutical company submitted updated data to the FDA, though that still did not show a statistically significant improvement over Gazyva plus chlorambucil.

“We were very disappointed to see that the recently updated overall survival data showed an increasing survival imbalance in favor of the control arm. Accordingly, we and our advisors determined that we should withdraw the BLA/sNDA for U2 in CLL,” Michael S. Weiss, chairman and CEO of TG Therapeutics, said in the release.

Additionally, TG therapeutics will be withdrawing Ukoniq from its already approved indications: the treatment of adults with marginal zone lymphoma (MZL) who had received at least one anti-CD20—based drugs, as well as for those with follicular lymphoma who received three or more prior drugs. This decision was based off TG Therapeutics’ withdrawal of the drug’s CLL and SLL indications.

While Weiss said in the statement that he thanks patients, families and clinicians who, “worked with us in our search for novel treatment options for patients with B-cell malignancies,” TG Therapeutics will reportedly be shifting gears in their development of U2, and instead focus on developing the therapy for patients with multiple sclerosis (MS).

“While we had hoped to bring U2 to patients with CLL, this will now permit us to focus our attention, passion and energy to building out our multiple sclerosis and autoimmune platform. With our ublituximab BLA pending for patients with relapsing forms of multiple sclerosis and a PDUFA goal date of Sept. 28, 2022, we are excited about the possibility of bringing ublituximab to patients with RMS,” Weiss concluded. “If approved, we believe the differentiated profile of ublituximab with its one-hour infusion will be welcomed by the MS community.”

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