Shares in BioLineRx ($BLRX) went on a brief roller-coaster ride following the release of Phase II data, popping by 16% in premarket trading before dropping a similar amount once the day began proper. The seesawing stock price was triggered by a press release about BioLineRx's Phase II acute myeloid leukemia study, in which the company called the trial a success but presented little data.
BioLineRx VP Arnon Aharon
Tel Aviv, Israel-based BioLineRx limited the efficacy section of the release to the composite complete remission rate. Among the 39 participants with relapsed or refractory acute myeloid leukemia who received up to two cycles of BL-8040 at doses of 1 mg/kg or higher in addition to the chemotherapy cytarabine, 38% were classed as complete remissions by the composite measure. BioLineRx also said the drug was safe and well tolerated, with no major adverse events reported. Safety was the primary outcome measure of the trial.
While BL-8040 appears to have succeeded by this primary safety measure, question marks hang over the extent to which the results are encouraging in other regards, in part because the top-line data released by BioLineRx is limited in scope. BioLineRx plans to present more detailed data an upcoming scientific conference. As such, the composite complete remission rate is the only current evidence of the efficacy of CXCR4 antagonist BL-8040. And, when compared to data generated in studies of other treatment regimens, it falls short of making a convincing case in favor of the drug.
A review of salvage chemotherapy regimens in patients with relapsed or refractory acute myeloid leukemia published in the Journal of Clinical Medicine last year suggests the performance of BL-8040 is comparable to that of existing options. Cytarabine, the chemotherapy given in the BioLineRx trial, has induced complete response rates ranging from 32% to 47% when delivered in isolation. When the chemotherapy is given as part of a cocktail of treatments, researchers have reported complete response rates as high as 61%.
As a caveat, comparing data across trials can lead to false conclusions. BioLineRx, for its part, thinks the comparator arm of a Phase III trial run by Sunesis Pharmaceuticals is the closest to an apples-to-apples comparison with its study. The placebo-plus-cytarabine arm of the Sunesis' trial, data from which were presented in 2014, achieved a complete response rate of 18.6%.
Doubts about whether the data are encouraging for BioLineRx contributed to the stock closing down 9% and continuing to slide in after-hours trading on the day of the release. For its part, BioLineRx has identified positives in the study data. "Importantly, the data suggest, for the first time, a correlation between improved clinical response and patients with a high disease burden in the bone marrow, along with a lower peripheral circulation of AML blasts at baseline," the company wrote. "This finding may serve as a biomarker for patient selection in future BL-8040 AML studies."
- read the release