ELEVATE TN: Acalabrutinib ups PFS in treatment-naïve CLL patients
Acalabrutinib, combined with obinutuzumab or used as monotherapy, significantly improves progression-free survival (PFS) by 80–90 percent vs obinutuzumab plus chlorambucil in patients with previously untreated chronic lymphocytic leukaemia (CLL), results of the phase III ELEVATE TN trial have shown.
The trial, reported at the American Society of Hematology 61st Annual Meeting (ASH 2019), achieved its primary endpoint of independent review committee (IRC)-assessed PFS with acalabrutinib plus obinutuzumab (A+O) vs obinutuzumab plus chlorambucil (O+Clb). [Sharman JP, et al, ASH 2019, abstract 31]
“At a median follow-up of 28 months, median IRC-assessed PFS was not reached in the A+O arm vs 22.6 months in the O+Clb arm, with a hazard ratio [HR] of 0.10 [95 percent confidence interval (CI), 0.06 to 0.18; p<0.0001], translating into a 90 percent reduction in risk of disease progression or death with A+O vs O+Clb,” reported investigator Dr Jeff P. Sharman of the Willamette Valley Cancer Institute and Research Center in Eugene, Oregon, US.
“Acalabrutinib monotherapy also significantly improved PFS vs O+Clb. Among patients treated with acalabrutinib monotherapy, median IRC-assessed PFS was not yet reached, and the risk of disease progression or death was reduced by 80 percent vs those treated with O+Clb [HR, 0.20; 95 percent CI, 0.13 to 0.31; p<0.0001],” he continued.
Estimated PFS rates at 30 months were 90 percent with A+O, 82 percent with acalabrutinib monotherapy, and 34 percent with O+Clb.
Importantly, the PFS improvement with A+O or acalabrutinib monotherapy was consistent across subgroups analyzed, including patients with del(17p) (HR, 0.13 [95 percent CI, 0.04 to 0.46] and 0.20 [95 percent CI, 0.06 to 0.64], respectively), Sharman noted.
Median overall survival (OS) was not yet reached in any treatment arm. However, a trend towards improvement was seen with A+O (HR, 0.47; 95 percent CI, 0.21 to 1.06; p=0.0577) and with acalabrutinib monotherapy (HR, 0.60; 95 percent CI, 0.28 to 1.27; p=0.1556), despite crossover of 25 percent of patients in the O+Clb arm to the acalabrutinib monotherapy arm upon IRC-confirmed disease progression. Estimated 30-month OS rates were 95 percent, 94 percent and 90 percent, respectively.
In terms of treatment response, IRC-assessed overall response rate (ORR) was 94 percent with A+O vs 79 percent with O+Clb (p<0.0001), and was 85 percent with acalabrutinib monotherapy. Complete response was achieved in 13 percent of patients in the A+O arm vs 5 percent of those in the O+Clb arm.
In the ELEVATE TN trial, 535 treatment-naïve CLL patients (median age, 70 years) were randomized to receive A+O (n=179), acalabrutinib monotherapy (n=179), or O+Clb (n=177). At baseline, 69 percent of patients had high-risk disease and 12 percent had very-high-risk disease, as measured by the CLL International Prognostic Index score.
Acalabrutinib, given orally at 100 mg BID until disease progression or unacceptable toxicity in the trial, was most commonly associated with headache as an adverse event (AE). Headache of any grade and grade ≥3 was reported in 40 percent and 1 percent of patients in the A+O arm, as well as 37 percent and 1 percent of those in the acalabrutinib monotherapy arm, compared with 12 percent and 0 percent of those in the O+Clb arm.
Any-grade atrial fibrillation was reported in 3 percent of patients treated with A+O, 4 percent of those treated with acalabrutinib monotherapy, and 1 percent of those on O+Clb,
Overall, grade ≥3 serious AEs were reported in 33 percent of patients in the A+O arm, 30 percent of patients in the acalabrutinib monotherapy arm, and 20 percent of patients in the O+Clb arm. Treatment discontinuation due to AEs was required in 11 percent, 9 percent and 14 percent of the patients, respectively.