Abstract 330P
Background
Tarlatamab has received accelerated FDA approval for patients with extensive-stage small cell lung cancer (SCLC) who progressed on or after platinum-based chemotherapy, based on objective response rate (ORR) and duration of response in the DeLLphi-301 trial. Due to lack of a comparator in DeLLphi-301, this study evaluated the relative efficacy of tarlatamab against real-world physicians’ choice of therapies.
Methods
Patients from DeLLphi-301 who received tarlatamab 10 mg (n=97) in the third-line setting and beyond and patients from a USbased electronic health record derived de-identified database who met key eligibility criteria of DeLLphi-301 and received comparator therapies for SCLC after at least 2 prior therapies (n=184) were compared. Propensity score (PS) weighting approach was used to adjust for differences in key baseline prognostic factors between the two cohorts. Overall survival (OS), progression-free survival (PFS), time to treatment discontinuation (TTD), time to next treatment or death (TTNTD), and ORR were compared after weighting. Hazard ratios (HRs) and odds ratio (OR) were calculated using weighted Cox and logistic regression models. Sensitivity analyses were conducted using an alternative set of prognostic factors and definition of PFS.
Results
The key baseline prognostic factors were balanced between the two cohorts and tarlatamab was associated with significantly longer OS, PFS, TTD, and TTNTD, and a higher ORR versus comparator therapies after PS weighting. The HRs (95% confidence interval [CI]) for tarlatamab versus comparator therapies were 0.45 (0.30, 0.68) for OS, 0.61 (0.43, 0.90) for PFS, 0.57 (0.39, 0.84) for TTD, and 0.45 (0.30, 0.66) for TTNTD. For ORR, tarlatamab had an OR of 2.80 (95% CI: 1.44, 5.83) versus comparator therapies. Sensitivity analyses showed similar results, reaffirming the robustness of the estimates.
Conclusions
Results suggest that tarlatamab offers clinical benefit relative to treatments used in real-world practice. This supports the use of tarlatamab in previously treated SCLC, which has historically been associated with poor outcomes due to aggressive nature of SCLC and limited treatment options.
Legal entity responsible for the study
Amgen Inc.
Funding
Amgen Inc.
Disclosure
U. Tapan: Financial Interests, Personal, Advisory Role: Amgen, GSK. R. Takundwa, J.Wang, X. Pundole, M. Pastel, F. Dirnberger: Financial Interests, Personal, Full or part-time Employment: Amgen; Financial Interests, Personal, Stocks/Shares: Amgen. G. Sajeev, X. Chai, H. Yang: Financial Interests, Institutional, Funding: Amgen.