Tarlatamab dosing for small cell lung cancer (SCLC) may soon offer pharmacists more scheduling flexibility, according to new data from the DeLLphi-309 study. Results presented at the 2026 World Conference on Lung Cancer show that less frequent administration—every 3 or 4 weeks—can maintain efficacy, safety, and pharmacokinetic profiles similar to the established every-2-week regimen.
The study evaluated whether 20 mg every 3 weeks or 30 mg every 4 weeks could replicate the survival benefits of the standard 10 mg every 2 weeks dose, which previously demonstrated superior overall survival compared to chemotherapy in the DeLLphi-304 trial. Adults with SCLC progressing after platinum-based chemotherapy were randomized to one of the three regimens, each preceded by a 1-mg step dose.
The primary endpoint was confirmed objective response rate (ORR) by blinded independent central review. As of the May 7, 2026 data cutoff, 252 patients were analyzed. The ORR was 40% for the every-2-week regimen, 31% for every-3-week dosing, and 27% for every-4-week dosing. Median progression-free survival was 4.2, 4.1, and 2.7 months, respectively, while six-month overall survival rates were 72%, 85%, and 69%. Median OS remained unreached after roughly 9 months of follow-up.
While the extended intervals show promise, the data carries limitations. No formal statistical comparisons were prespecified, meaning results are descriptive rather than definitive. The study also lacks the longer-term OS data available from the original DeLLphi-304 trial, which reported 12-month survival rates.
Safety profiles were broadly consistent across regimens, though extended-interval dosing saw numerically higher rates of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). CRS occurred in 60% to 70% of patients, mostly grade 1 or 2, while ICANS affected 6% to 12%. Steady-state trough concentrations remained comparable across schedules.
Andrew Li, PharmD, BCOP, a clinical oncology pharmacist at Providence Regional Medical Center Everett-Colby Campus, noted that while the findings are encouraging, they require cautious interpretation. “The feasibility of extending an every-2-week treatment cycle to an every-3-week or every-4-week interval is certainly an endeavor worth examining, as that option can make a meaningful quality-of-life improvement for patients,” he said.
The study suggests pharmacists could gain more scheduling flexibility, potentially easing logistical strain for patients and infusion centers. Fewer visits could improve quality of life for those with transportation or access challenges. However, the lack of statistical rigor and limited follow-up data mean these findings are best viewed as hypothesis-generating rather than practice-changing.
“These data suggest that the tarlatamab 20 mg every-3-week and 30 mg every-4-week regimens may offer treatment flexibility for patients with SCLC,” said Jonathan Goldman, MD, of the University of California Los Angeles, who presented the findings.
“Overall, with the data as it is currently reported, providers and pharmacists alike may be open to exploring and utilizing the extended intervals but would likely appreciate additional data or analysis that is released,” said Li.
The study was published as part of the 2026 World Conference on Lung Cancer proceedings, with full details available in the clinical trial registry (NCT06745323).
