Building on the established clinical activity of intravenous (IV) tarlatamab, the phase IB DeLLphi-308 study marks the first clinical evaluation of subcutaneous (SC) tarlatamab delivery in patients with extensive-stage small cell lung cancer (ES-SCLC).
Researcher Pedro Rocha, MD, PhD, said subcutaneous administration may improve convenience and reduce adverse events, including cytokine release syndrome (CRS). Dr. Rocha of Vall d’Hebron University Hospital, Barcelona, Spain, indicated that subcutaneous tarlatamab achieved promising antitumor activity with a manageable safety profile in a heavily pretreated population.
He shared the results during a press briefing on Saturday, September 12, during the 2026 World Conference on Lung Cancer (WCLC) in Seoul, Republic of Korea. Dr. Rocha will also present the findings during a session titled Expanding Therapeutic Frontiers in SCLC: ADCs, T-Cell Engagers, and First-Line Strategies. The session will take place on Tuesday, September 15, at 12:30 KST in Room E5, Conference Room E, Floor 3.
Expanding Therapeutic Frontiers in SCLC: ADCs, T-Cell Engagers, and First-Line Strategies
Tuesday, September 15, at 12:30 KST • Room E5, Conference Room E, 3F
From first-line and perioperative treatment strategies and emerging tarlatamab regimens to novel B7-H3-targeted antibody-drug conjugates, the mini oral session will highlight key advances in SCLC. LEARN MORE
The open-label multicenter study enrolled previously treated patients with ES-SCLC following platinum-based therapy. The primary objective was safety and tolerability, while secondary objectives included pharmacokinetics (PK), antitumor activity, and immunogenicity.
Part one of the study centered around dose exploration, where investigators evaluated targeted doses of SC tarlatamab of 10 mg (n = 20) and 15 mg (n = 40) administered every two weeks (Q2W).
SC tarlatamab demonstrated a manageable safety profile in a heavily pretreated population with advanced disease, with low rates of treatment-related adverse events (TRAEs) and a treatment discontinuation rate of 2%, despite a reduced monitoring schedule during the expansion phase of the study.
“The findings from DeLLphi-308 suggest that a 15 mg subcutaneous tarlatamab dose can achieve serum exposures comparable to the approved 10 mg intravenous dosing administered every two weeks while maintaining a favorable safety profile.”
— Pedro Rocha, MD, PhD
Key adverse events in patients treated with 15 mg Q2W SC tarlatamab included CRS (38%), injection site reactions (50%), dysgeusia (48%), and neutropenia (10%). Notably, CRS events were lower than historically reported with IV tarlatamab; all events were grade 1 or 2, and no events required dose interruption or discontinuation.
Those in the 15 mg cohort achieved dose exposures comparable to the established 10 mg IV Q2W regimen and were selected for the study’s part two dose-expansion stage. At 15 mg every two weeks, SC tarlatamab achieved results comparable to 10 mg IV tarlatamab in patients with ES-SCLC, with an overall response rate (ORR) of 30%. Median progression-free survival (PFS) was 3.7 months, and median overall survival (OS) was 11.7 months.
“The findings from DeLLphi-308 suggest that a 15 mg SC tarlatamab dose can achieve serum exposures comparable to the approved 10 mg IV dosing administered every two weeks while maintaining a favorable safety profile,” Dr. Rocha said. “The predominantly low-grade CRS events and preliminary antitumor activity support continued investigation of this more convenient route of administration.”
The phase III DeLLphi-315 study will evaluate the safety and efficacy of SC tarlatamab versus IV tarlatamab in patients with SCLC.
Please refer to the 2026 WCLC Scientific Program for the most up-to-date schedule information.
