Dr Lin on the Safety of NKTR-255 in Enhancing Immune Recovery Post-Chemoradiation in Locally Advanced NSCLC

There was adequate restoration of lymphocyte counts after chemoradiation therapy with NKTR-255. Now, after the first 10 patients, the study continues to enroll [with a goal of] an additional 20 patients for a total of 30 patients on the study. We're going to look at the continued evaluation of safety, lymphocyte recovery, [and] preliminary efficacy in this group of patients.”

Steven H. Lin, MD, PhD, physician-scientist, radiation oncologist, professor, Department of Radiation Oncology, Division of Radiation Oncology, The University of Texas MD Anderson Center, discusses findings from the phase 2 RESCUE study (NCT05632809) evaluating NKTR-255, a novel polymer-conjugated recombinant human interleukin 15 agonist, in patients with locally advanced non-small cell lung cancer (NSCLC) with radiation-induced lymphopenia following concurrent chemoradiation. Data were presented by Lin and colleagues at the 2024 SITC Annual Meeting.

The study evaluated NKTR-255 in combination with durvalumab (Imfinzi), and the combination was started following the completion of chemoradiation. The agents were administered on day 0 after chemoradiation and administered once every 4 weeks for up to 1 year. The primary objectives focused on safety and lymphocyte recovery, Lin begins. Preliminary efficacy was also assessed as a secondary end point.

Findings showed that in the first cohort of 10 patients, 9 experienced a complete recovery of lymphocyte counts by week 8, Lin explains. He notes that data from historical controls show that lymphocyte recovery would be expected in only a small number of patients at this time point, indicating that NKTR-255 plays a role in lymphocyte recovery.

In terms of safety, Lin noted that NKTR-255 was well tolerated when combined with durvalumab. Low-grade adverse effects including mild fever, chills, and fatigue were reported, and no high-grade AEs were observed, Lin notes. Grade 3 pneumonitis was reported in 1 patient, which was consistent with expected rates in this population, Lin adds.

As patients continue to enroll on the study, investigators will continue to evaluate the safety of NKTR-255 and the lymphocyte recovery achieved by patients, along with additional analysis to examine efficacy, Lin concludes.