Combo proves ‘beneficial’ for ‘unfit’ CLL patients
STOCKHOLM—Obinutuzumab plus chlorambucil (G-Clb) is a “valid and beneficial” frontline treatment option for “unfit” patients with chronic lymphocytic leukemia (CLL), according to a speaker at the 23rd Congress of the European Hematology Association (EHA).
Final results from the CLL11 study have revealed additional benefits of G-Clb over rituximab plus chlorambucil (R-Clb) in patients with previously untreated CLL and comorbidities.
Prior results from this study showed that G-Clb produced higher response rates and prolonged progression-fee survival (PFS) compared to R-Clb.
Now, with a median follow-up of 5 years, researchers have found that G-Clb prolongs overall survival (OS) and time to next treatment (TTNT) as well.
Valentin Goede, MD, of the University Hospital Cologne in Germany, presented these results during the Presidential Symposium of the EHA Congress (abstract S151).
The study was sponsored by Hoffmann-La Roche.
CLL11 enrolled patients with previously untreated CLL and coexisting medical conditions. They were randomized to receive six 28-day cycles of Clb alone, G-Clb, or R-Clb.
In stage 1, researchers compared G-Clb (n=238) to Clb alone (n=118) and R-Clb (n=233) to Clb alone (n=118). In stage 2, they compared G-Clb (n=333) and R-Clb (n=330).
“The treatment arms were well-balanced, not just with regard to patient [characteristics] but also with disease characteristics,” Dr Goede said.
Overall, the median age was 73 (range, 39-90), the median Cumulative Illness Rating Scale score was 8, and the median creatinine clearance was 62 mL/min.
Efficacy: G-Clb vs Clb
The median observation time for G-Clb vs Clb was 62.5 months.
The median PFS was 31.1 months in the G-Clb arm and 11.1 months in the Clb arm. The 5-year PFS rates were 25% and 2%, respectively. The hazard ratio (HR) was 0.21 (P<0.0001).
The median OS was not reached in the G-Clb arm and was 66.7 months in the Clb arm. The 5-year OS rates were 66% and 53%, respectively. The HR was 0.68 (P=0.0196).
Thirty-nine percent of the G-Clb arm died, as did 49% of the Clb arm. The main causes of death were adverse events (AEs) and disease progression.
Efficacy: G-Clb vs R-Clb
The median observation time for G-Clb vs R-Clb was 59.4 months.
The median PFS was 28.9 months in the G-Clb arm and 15.7 months in the R-Clb arm. The 5-year PFS rates were 23% and 9%, respectively. The HR was 0.49 (P<0.0001).
“The median PFS was nearly doubled, from approximately 15 months in the rituximab arm to almost 30 months in the obinutuzumab arm,” Dr Goede said. “And this translated into a clinically meaningful prolongation of time to next treatment.”
The median TTNT was 56.4 months in the G-Clb arm and 34.9 months in the R-Clb arm. At 5 years, TTNT rates were 49% and 32%, respectively. The HR was 0.58 (P<0.0001).
“In the rituximab arm, the median time to next treatment was a little greater than 2.5 years, and, in the obinutuzumab arm, it was almost 5 years,” Dr Goede said. “From a clinical perspective, I would consider treatment-free intervals of that duration as highly relevant and beneficial in an elderly population.”
The median OS was not reached in the G-Clb arm and was 73.1 months in the R-Clb arm. The 5-year OS rates were 66% and 57%, respectively. The HR was 0.76 (P=0.0245).
“This difference is clinically meaningful, and it is also remarkable in the context of the long follow-up, given the fact that approximately half of the patients have received at least 1 salvage treatment in the meantime,” Dr Goede said.
