Eli Lilly and Co. said that its Bruton's tyrosine kinase, or BTK, inhibitor Loxo-305 showed responses in a dose-escalation trial for certain patients that had already received treatments, including patients with BTK therapy resistance or intolerance.
Tumors reduced for all patients with chronic lymphocytic leukemia, or CLL, participating in the study and responses were seen in patients that had either established a resistance to prior BTK therapy, were intolerant to BTK therapy or had a resistance to prior B cell lymphoma 2 therapy, according to Eli Lilly's interim results. Additionally, three of eight patients with mantle cell lymphoma, or MCL, responded to the treatment.
The company presented the data from its first-in-human phase 1/2 trial, called BRUIN, at the American Society of Hematology's annual meeting.
Of the 16 patients with CLL participating in the study, 10 responded to the drug treatment. All 10 patients remain in response and all 16 patients with CLL remain part of the study. All patients with MCL that responded to the treatment are still in response and continuing with the study. Three patients with MCL discontinued therapy in cycle 1 due to the disease progressing, according to the statement.
A total of 28 patients were part of the study on a five dose-escalation, beginning with 25-milligram doses of the blood cancer drug and ending at 200-milligram doses.
"We saw objective responses in dose cohort 1 and have not identified a maximum tolerated dose," Anthony Mato, director of the CLL Program at Memorial Sloan Kettering Cancer Center and the presenting author, said in a Dec. 8 press release. "These data suggest that LOXO-305 has the required selectivity profile and human target coverage to maximize the full potential of this molecular target, combine well with other agents, and perhaps, even move to earlier lines of therapy."
Side effects attributed to Loxo-305 included acute lymphocytosis, an increase in the total number of the white blood cell sub-type lymphocytes. The reaction was expected and resolves over time, according to the press release. Milder side effects of the treatment included fatigue and diarrhea.
Eli Lilly obtained Loxo-305 as part of its $8 billion acquisition of Loxo Oncology Inc. in January.