LA JOLLA, CALIF. – Phase 1 results suggest cobomarsen is well tolerated and can maintain or improve responses in patients with previously treated adult T-cell leukemia/lymphoma (ATLL).
Five of eight ATLL patients studied experienced disease stabilization or improvement while receiving cobomarsen (MRG-106), an inhibitor of microRNA-155.
There were no grade 3/4 adverse events (AEs) or serious AEs related to cobomarsen in these patients.
Francine Foss, MD, of Yale Cancer Center in New Haven, Conn., and her colleagues presented these results at the annual T-cell Lymphoma Forum.
In this ongoing trial (NCT02580552), researchers are evaluating cobomarsen in patients with B- and T-cell lymphomas, including mycosis fungoides and ATLL.
Results are available for eight patients with previously treated ATLL. These patients had received a median of 4 (range, 1-10) prior systemic therapies, and they had a median age of 51 years (range, 40-68).
The patients received three loading doses of cobomarsen during the first week of cycle 1, followed by weekly dosing. All patients have received cobomarsen as a 600 mg intravenous infusion. They can remain on cobomarsen until they progress, experience clinically significant side effects, cannot tolerate the drug, or the trial is terminated.
The researchers have measured efficacy at least monthly by monitoring tumor cell burden in the peripheral blood and lymph nodes, as well as evaluating changes in skin involvement.
Stabilization and response
“Initially, we saw some very good responses in patients who had escalating disease. In other words, their disease was progressing after conventional chemotherapy,” Dr. Foss said. “They went on this microRNA, [and] their disease stabilized and then regressed. We saw, subsequently, in another three or four patients, the same pattern of activity.”
In all, five patients achieved or maintained a response while on cobomarsen. All five were still receiving the drug at the data cutoff on Dec. 13, 2018.
Two of these patients had acute disease and were in partial response (PR) at baseline. These patients had received cobomarsen for 87 days and 401 days as of the data cutoff.
The other three patients still receiving cobomarsen at the cutoff had lymphomatous disease. At baseline, two of the patients were in PR and one had stable disease.
The two patients in PR at baseline had received cobomarsen for 80 days and 366 days at the data cutoff. The patient with stable disease had received the drug for 161 days.
Progression and withdrawal
There were three patients who withdrew from the study because of disease progression. Two of these patients were relapsing with significant skin involvement at baseline.
One of the patients discontinued cobomarsen after 23 days of treatment. The other patient received cobomarsen for 91 days and left the study, then re-enrolled and received cobomarsen for another 42 days before withdrawing from the study again.
The third patient had relapsed lymphomatous disease at baseline. This patient had a mixed response to cobomarsen, with some nodes decreasing in size and others increasing. She discontinued cobomarsen after 9 days.
“It’s still early on in our experience with ATLL, so we don’t really know yet who the patient is that’s going to respond – what are the clinical features that would predict response in these patients,” Dr. Foss said. “And we’re still really trying to understand how we give the drug to these patients, for how long, and whether or not we can change the dosing interval. But, nevertheless, we have some very interesting data.”