TG shrugs off another delay, but history is against it

Yet another delay to TG Therapeutics’ Unity-CLL study provides yet more evidence that it has already failed. Not that this has discouraged the company, whose chief executive, Michael Weiss, yesterday told analysts that the delay to reaching a prespecified number of progression-free survival events was “very positive ... because the longer it takes for the events to occur should point to a greater than expected benefit for the [active cohort]”. Such a view ignores the countless event-driven studies whose delays had similarly been presented as positive, only to blow up on final analysis because subjects in the control cohorts were also progressing less fast; the lesson was most recently learned by Bavarian Nordic. Unity-CLL pits ublituximab and umbralisib – TG’s anti-CD20 antibody and a PI3K delta inhibitor respectively – against Roche’s Gazyva plus chlorambucil. Notably it does not include Roche/Abbvie's highly efficacious newcomer Venclexta, so might lack real-world relevance, and its earlier failure to show an ORR benefit had already made hitting PFS a long shot. In a further twist Unity-CLL is now being amended to allow an interim PFS readout to prevent yet more delays, making this one of the most extensively overhauled pivotal studies in biotech.

The shifting timeline of TG's Unity-CLL study
Date Update
Sep 2017 Secondary endpoint of ORR is touted as key to supporting accelerated approval, data due 2018
Aug 2018 ORR readout delayed from Q2 to end of summer
Sep 2018 ORR analysis draws a blank
Accelerated approval plan scrapped
Focus switches to PFS, with data due late 2019
Dec 2019 primary completion date changes from Nov 2019 to Nov 2020
Company calls this an admin issue, and says PFS readout is expected Q1 2020
Mar 2020 PFS events still short of prespecified number
New timeline has PFS events being hit in Apr 2020, with results a month later
TG says FDA has agreed extra interim analysis for PFS, preserving possible 2020 YE filing timeline 
Source: company announcements.

Share This Article