Umbralisib offers hope for patients with relapsed/refractory marginal zone lymphoma
Patients with relapsed/refractory (R/R) marginal zone lymphoma (MZL) responded well to the novel next-generation Pl3K-delta inhibitor umbralisib, according to updated results of the UNITY-NHL* trial presented at AACR 2019.
“Umbralisib is a small-molecule inhibitor that targets PI3K-delta, which is a component of a signalling pathway that has a key role in promoting the survival and expansion of many types of cells, and has also been shown to uniquely inhibit casein kinase-1 epsilon,” said study lead author Dr Nathan Fowler from the Department of Lymphoma and Myeloma, Division of Cancer Medicine at MD Anderson Cancer Center in Houston, Texas, US.
This phase II trial involved 69 patients with R/R MZL who had an ECOG performance status of ≤2 and were previously treated with ≥1 CD20 monoclonal antibody-containing regimen. Participants received oral umbralisib 800 mg once daily and continued treatment until disease progression or intolerable toxicity. [AACR 2019, abstract CT132]
At a median follow-up of 9.6 months, only 38 patients (median age, 67 years) were eligible for evaluation, majority of whom had extranodal MZL subtype (n=23), while the rest either had the nodal or splenic subtype (n=8 and 7, respectively).
Patients who received umbralisib achieved an objective response rate of 55 percent, with four and 17 patients having complete and partial responses, respectively.
In addition, 11 patients had stable disease, with a clinical benefit rate of 84 percent, and 91 percent of the patients had tumour reductions.
Patients treated with umbralisib also showed a progression-free survival rate of 71 percent at 12 months, while the median duration of response was not reached at 8.4 months.
The most common adverse events (AEs) of any grade were diarrhoea (45 percent), nausea (29 percent), fatigue (26 percent), headache (26 percent), cough (24 percent), and decreased appetite (21 percent). The most frequent grade3–4 AEs were neutropenia and febrile neutropenia (8 percent and 5 percent, respectively).
“All the AEs we have seen in the trial are to be expected with this class of drugs ... Moreover, we were able to manage the side effects for the patients, making umbralisib a well-tolerated treatment,” Fowler noted.
“The AE and clinical activity data are highly encouraging at this early timepoint … [and] our exciting results suggest that this oral targeted therapeutic has significant activity against R/R MZL,” said Fowler, who pointed to the recent (January 2019) US FDA**-granted breakthrough therapy designation for this drug for adults with MZL previously treated with at least one anti-CD20 regimen.
“We are excited to continue following patients for a longer time to further establish the long-term activity and side effects of umbralisib. With the results reported so far, umbralisib has the potential to make a real difference for patients with R/R MZL,”he added.
*UNITY-NHL: Study to assess the efficacy and safety of ublituximab + TGR-1202 with or without bendamustine and TGR-1202 alone in patients with previously treated non-Hodgkins lymphoma
**FDA: Food and Drug Administration