The red flags keep coming with TG Therapeutics

The writing has been on the wall for PI3K inhibitors for some time, so it is surprising that TG Therapeutics’ after-market announcement on Friday, disclosing the end of its own PI3K asset, Ukoniq, contained enough sting to wipe 22% off the stock. Commercial hopes must have plummeted after last year’s disclosure of an imbalance of deaths in Ukoniq’s Unity-CLL trial, a signal that has been confirmed on later analysis. The drug will be withdrawn from sale, as will an application to sell Ukoniq in combination with TG’s anti-CD20 MAb, ublituximab, in lymphoma. It is also surprising that TG is still worth almost $1bn. This is based on hopes for ublituximab in multiple sclerosis, on which the FDA decides in September. The remaining risks are numerous. They include believing the company’s assertions that the MS application will not affected by the disaster in cancer; this cannot be ruled out considering ublituximab had a role in the Unity-CLL trial. Also potentially problematic is that almost half the recruits to the MS pivotal programme were based in Ukraine and Russia. Faith in TG’s ability to compete against giants in the MS space does also not come easy. One thing is certain: the TG saga is far from over.