TORONTO – in the first interim results from the multicenter, open-label, phase 3 trial.
In fact, the primary endpoint of the study – blinded independent review committee–assessed progression-free survival (PFS) – was met at this first analysis. The next-generation ALK inhibitor brigatinib reduced the chance of progression or death by 51% as compared with crizotinib – the current first-line standard of care in this population, D. Ross Camidge, MD, reported at the Worldon Lung Cancer.
“At a median follow-up of 9-11 months, 26% [of 137 patients] on the brigatinib arm and 46% [of 138 patients] on the crizotinib arm had experienced a PFS event. Median PFS was not reached for the brigatinib arm and was 9.8 months for the crizotinib arm; the hazard ratio for progression or death was 0.49 and highly statistically significant,” said, director of thoracic oncology and the Joyce Zeff Chair in Lung Cancer Research at the University of Colorado Cancer Center, Aurora, at the meeting sponsored by the International Association for the Study of Lung Cancer.
The findings were published simultaneously in the New England Journal of Medicine.
The 12-month PFS rate estimate was 67% for brigatinib and 43% for crizotinib, and the investigator-assessed hazard ratio for PFS was 0.45. Overall survival data are immature, Dr. Camidge added, noting that the PFS hazard ratios for those with versus those without prior chemotherapy were 0.35 and 0.55, respectively.
“PFS consistently favored brigatinib across all other subgroups,” he said. “Although the confidence intervals overlap, the effect size appears greater among those with baseline [CNS] disease than among those without [HR, 0.2 vs. 0.72].”
Data suggest that CNS progression among those with CNS disease at baseline tends to be an earlier event than either extra-CNS progression in general or CNS progression in those without baseline CNS disease. “Consequently, this first interim analysis may be preferentially emphasizing drug efficacy differences within the subgroup in whom the earlier progression events are occurring,” Dr. Camidge said.
As for overall objective responses, the rates were numerically higher with brigatinib versus crizotinib (70% vs. 60%), but were not statistically different in the two groups. “However, the median duration of confirmed responses was not reached for brigatinib and [was] 11.1 months with crizotinib, with the 12-month [probability] of sustained response being 75% for brigatinib and 41% for crizotinib,” he added.
Further, among those with measurable CNS lesions, brigatinib demonstrated a significantly higher intracranial response rate of 78% versus 29% (odds ratio, 10.42), and when those with nonmeasurable CNS disease were included in the intracranial response assessment, the odds ratio was 13.
Median intracranial PFS among those with CNS involvement at baseline was not reached in the brigatinib arm versus 5.6 months with crizotinib, for a highly statistically significant hazard ratio of 0.27. “Which, given that the median PFS for crizotinib in the overall population ... was 9.8 months, again emphasizes how CNS events in this subgroup tend to occur early,” he noted.
Study subjects had stage IIIB/IV ALK-positive non–small cell lung cancer (NSCLC) based on local ALK testing, Eastern Cooperative Oncology Group performance status of 0-2, no more than one prior systemic therapy for locally advanced/metastatic NSCLC, and no prior ALK inhibitor therapy, Dr. Camidge said, noting that asymptomatic, untreated brain metastases were allowed and crossover to the brigatinib arm was permitted for those with blinded independent review committee–assessed progression on crizotinib.
Those randomized to the brigatinib arm had a median age of 58 years and received 180 mg daily with a 7-day lead-in at 90 mg. Those randomized to the crizotinib group had a median age of 60 years and received 250 mg twice daily. Prior chemotherapy for advanced disease was received by 26% and 27% and brain metastasis was present in 29% and 30% of patients in the arms, respectively.
The most common treatment-emergent adverse events of grade 3 or higher in the brigatinib patients were laboratory abnormalities such as creatinine phosphokinase, lipase, and amylase increases, and the most common in the crizotinib group were gastrointestinal effects, transaminitis, bradycardia, peripheral edema, and vision disturbances.
Discontinuations caused by adverse events occurred in 12% and 9% of the brigatinib and crizotinib patients, respectively, he said. No clinical cases of pancreatitis occurred in either arm, there was no difference in the incidence of any grade myalgia or musculoskeletal pain between arms, and there was no grade 3 or greater myalgia or musculoskeletal pain reported.
Early-onset interstitial lung disease, however, “appears to be a unique side effect of brigatinib,” Dr. Camidge noted.
Although interstitial lung disease/pneumonitis occurred in both groups, onset at days 3-8 after treatment initiation occurred only with brigatinib, he said, adding that “it only occurred in 3% of cases – half the rate seen in the postcrizotinib setting.”
Thestudy established crizotinib as the standard first-line therapy for advanced ALK-rearranged NSCLC, showing superior PFS versus pemetrexed doublet chemotherapy (HR, 0.45), but median PFS with crizotinib in that trial was only 10.9 months, Dr. Camidge said.
The next-generation ALK inhibitor brigatinib, however, has demonstrated broad preclinical activity against ALK resistance mutations, has excellent CNS penetration, and is the only ALK inhibitor with marked activity against multiple epidermal growth factor receptor–mutant cell lines, he said. “It has already shown significant activity both within the CNS and extracranially in the postcrizotinib setting, where it has consistently demonstrated the longest reported median PFS [up to 16.7 months] of any licensed or experimental ALK inhibitor.”
The ALTA-1L study provides a head-to-head comparison of brigatinib and crizotinib in a real-world setting, and the findings demonstrate that “brigatinib represents a promising new treatment for inhibitor-naive, ALK-rearranged NSCLC,” he said.
In a press statement, Dr. Camidge further stated that, based on these findings, brigatinib is set to become a first-line treatment option for ALK-positive lung cancer, adding that, “even with only 9-11 months of follow-up, the efficacy of brigatinib is clearly superior to crizotinib. A lot of the initial difference is driven by an effect on brain metastases, which tend to be an earlier progression event. However, once differences in control of disease outside the brain have time to manifest, it is possible the PFS improvement may increase.”
Both Dr. Camidge and invited discussant Fiona Blackhall, PhD, noted that the tolerability of brigatinib may be “even better in the real world,” as most of the 29% of patients on the brigatinib arm with adverse event–related dose reductions had “paper toxicities” for which the clinical impact is not well understood.
The rate of dose reductions for adverse events with brigatinib was higher in ALTA-1L than that seen in earlier studies of the second-generation ALK inhibitor alectinib, said, professor and chair in thoracic oncology at the University of Manchester (England).
“We need to be sure that these dose reductions are appropriate and not potentially compromising efficacy,” she added.
Dr. Blackhall also suggested that sequential use of crizotinib and other ALK inhibitors like brigatinib should be evaluated and that the potential impact of ALK inhibitor selection “on the spectrum and type of resistance mutations and mechanisms” should be considered.
“Brigatinib is a new first-line treatment option for patients with ALK-positive non–small cell lung cancer. ... But in the absence of direct comparison of next-generation ALK inhibitors, it is going to take some time before we can determine whether there is indeed – if there ever will be – a ‘best’ ALK inhibitor for our patients,” she said.
Dr. Camidge has received honoraria from Arrys/Kyn, AstraZeneca, Biothera, Celgene, Clovis Oncology, Daiichi Sankyo, G1 Therapeutics, Genoptix, Hansoh, Ignyta, Lycera, Mersana Therapeutics, Novartis, Orion, Revolution Medicines, Roche/Genentech, and Takeda, and has received research funding from ARIADTakeda. Dr. Blackhall reported research funding from Amgen, AstraZeneca, Novartis, and Pfizer, and has served has an advisory board member, consultant, or speaker for AbbVie, Boehringer Ingelheim, Cell Medica, Medivation, Merck, Regeneron, Roche, and Takeda.
SOURCE: Camidge DR et al. WCLC 2018, .