Poteligeo Proves Safe, Effective for ATL Patients in Clinical Setting

Poteligeo (mogamulizumab), an approved treatment for relapsed or refractory adult T-cell leukemia-lymphoma (ATL) patients in Japan, is also safe and effective in a real-world clinical setting, a postmarketing surveillance study found.

The study, “Safety and effectiveness of mogamulizumab in relapsed or refractory adult T-cell leukemia-lymphoma,” was published in the European Journal of Haematology.

ATL is a rare kind of non-Hodgkin’s lymphoma caused by a viral infection. It can be treated with aggressive chemotherapy or stem cell transplantation, but these treatment options aren’t always feasible, particularly for older patients.

ATL cells often express the chemokine receptor 4 (CCR4), which can drive these cells to proliferate uncontrollably, thus furthering disease progression. By targeting this receptor, Poteligeo can, at least in theory, stop these cancerous cells from growing or even kill them.

Kyowa Kirin‘s Poteligeo is approved in Japan for adult patients with CCR4-positive T-cell leukemia-lymphoma who have failed to respond (refractory) or whose disease progressed after an initial response (relapsed) to prior treatments. But after its approval, the regulatory agency in Japan requested that a surveillance study be conducted to determine the treatment’s safety and efficacy in clinical practice.

In this study, the researchers report the results from a clinical trial (UMIN000025368) of 523 ATL patients treated at 294 institutions in Japan between 2012 and 2018. The average age of patients was 67; nearly half the patients were over 70.

The patients were given 1 mg/kg of Poteligeo once weekly for eight weeks and were monitored for response to treatment and adverse side effects.

During Poteligeo therapy, 57.9% of patients showed a response — either complete or partial remission. At the end of treatment, 42% of patients had some response, so about 30% of the patients who initially responded to the treatment had eventual disease progression during the treatment. The average survival time from the start of treatment was 5.5 months.

Responses were best for tumors that were blood-based, with lower proportions of tumors located in the skin, liver, spleen, lymph nodes, or elsewhere showing responses.

Nearly three-quarters of patients experienced at least one adverse event, and about a third  experienced a serious side effect as a result of Poteligeo treatment. The most common side effects were disorders related to the infusion of the compound, skin disorders, and infections.

The researchers further analyzed the patients’ data to see whether particular clinical features might be predictive of better or worse responses to Poteligeo treatment. Unsurprisingly, patients with tumors rated as higher grade (i.e. more aggressive) tended to have poorer prognoses, as did those with lower levels of albumin, a protein that can be measured in the blood.

Interestingly, patients over 70 were not any more likely to have a poorer prognosis than younger patients. This suggests that Poteligeo might be a useful treatment for older patients for whom other treatments are unavailable.

“In clinical practice, the overall safety profile of mogamulizumab was manageable in most patients and was consistent with previous reports,” the researchers said. They also suggested that further studies to identify which patients are most likely to respond to Poteligeo might be a promising avenue.