The UKALL 2003 trial (NCT00222612) was designed to evaluate the effects of de-escalation of therapy in patients with ALL and a low-risk MRD profile, and treatment intensification in patients with ALL and a high-risk MRD profile. Participants in the low-risk MRD group were randomised to 1 (n=261) or 2 (n=260) delayed intensifications (DIs) of therapy. High-risk patients were randomised to standard therapy (n=266) or augmented therapy (n=267).
Dr Sujith Samarasinghe (Great Ormond Street Hospital, UK) presented the 10-year follow-up results. In the low-risk group, participants in the 1 DI arm displayed a higher relapse rate than those in the 2 DIs arm (8.3% vs 3.6%; P=0.04). However, overall survival rates were not significantly different between the 2 arms (97.1% vs 97.6%; P=0.5). According to Dr Samarasinghe, the increased rate of treatment-related deaths in the 2 DIs arm resulted in comparable overall survival rates for both low-risk groups. The relapse rate in the high-risk standard therapy arm was 14.2%, versus 9.2% in the high-risk augmented therapy arm (P=0.07).
The overall survival rates were not significantly different after 10 years (87.9% vs 90.7%; P=0.3). Among patients with B-precursor ALL, augmented therapy did result in a significant reduced risk of relapse (HR 0.54; P=0.03). Similarly, patients with high-risk cytogenetics displayed that relapse risk was significantly lower if they were treated with augmented therapy (22.1%) compared with those receiving standard therapy (52.4%; P=0.016). Dr Samarasinghe concluded that the long-term follow-up data of UKALL 2003 showed that modest therapy de-escalation is safe in patients with low-risk MRD profiles and that augmented therapy continued to display a favourable trend in patients with high-risk MRD profiles.
1. Samarasinghe S, et al. Ten Year Outcomes of UKALL 2003: A Randomised Clinical Trial of Adjusting Treatment Intensity Based on Minimal Residual Disease. O614, ASH 2021 Scientific Sessions, 11–14 December.