Dr Lau on Tarlatamab as Maintenance Therapy in Extensive-Stage SCLC

Sally Lau, MD, thoracic medical oncologist, Perlmutter Cancer Center, NYU Langone Health, discussed the efficacy results from the phase 1b DeLLphi-303 study (NCT03319940), which evaluated tarlatamab-dlle (Imdelltra) in combination with a PD-L1 inhibitor as first-line maintenance therapy following chemoimmunotherapy for patients with extensive-stage small cell lung cancer (ES-SCLC).

This is an open-label, multicenter study evaluated tarlatamab either in combination with carboplatin, etoposide, and durvalumab (Imfinzi) or atezolizumab (Tecentriq), followed by maintenance tarlatamab plus a PD-L1 inhibitor; or in combination with a PD-L1 inhibitor as a maintenance-only approach.

Traditionally, ES-SCLC has been managed with chemoimmunotherapy in the first line, Lau states. However, long-term disease control in ES-SCLC remains a challenge, with limited options available after progression, Lau notes.

Results from DeLLphi-303 study showed that a disease control rate of 62.5% was achieved with tarlatamab plus durvalumab (95% CI, 45.8%-77.3%) and tarlatamab plus atezolizumab plus atezolizumab (95% CI, 47.4%-76.0%), Lau explains. Notably, the median duration of disease control exceeded 9 months (95% CI, 3.9- not evaluable [NE]) and was 7.2 months (95% CI, 5.6-NE) in these respective groups, she adds.

Furthermore, the median progression-free survival rate at 9 months was 5.3 months (95% CI, 3.5-NE) and 5.6 months (95% CI, 3.5-8.5), respectively, which suggests that the addition of tarlatamab to a PD-1 inhibitor may improve outcomes compared with PD-L1 inhibition alone, Lau elaborates. This tail-end improvement in the PFS curve is promising for patients with extensive SCLC, a disease historically characterized by poor prognosis, she notes.

Although the overall survival (OS) data are still maturing, Lau highlights that there is a favorable trend with the tarlatamab regimen. At 9 months, the OS rate was 91.8% (95 % Ci, 76.6%-97.3%), an improvement not previously observed in this setting, she asserts.

Additional studies are necessary to confirm these findings and further investigate the long-term potential of tarlatamab in the maintenance setting, Lau concludes.