First-in-class DLL3-targeting BiTE could be the next big player in SCLC treatment: GlobalData

Small cell lung cancer (SCLC), comprising 15 per cent of lung tumors, is a highly aggressive form of malignancy. However, tarlatamab, a bispecific T-cell engager (BiTE) developed by Amgen, recently demonstrated potentially registrational data at the European Society for Medical Oncology (ESMO) 2023 Congress from the Phase II DeLLphi-301 trial.  The drug may become a promising lifeline for SCLC patients and is forecast to achieve peak sales of $788 million by 2029, according to GlobalData.

Verona Morina, Oncology and Hematology Analyst at GlobalData, comments, “The most recent results displayed by tarlatamab may reignite interest in the delta-like ligand 3 (DLL3) antigen present on tumor cells, a target that suffered a setback when AbbVie terminated Rova-T, an anti-DLL3 antibody-drug conjugate in 2019, due to its Phase III failure in the treatment of SCLC. DLL3 presents an intriguing therapeutic prospect for individuals with SCLC, given that around 85 per cent to 94 per cent of patients exhibit DLL3 expression on the surface of SCLC cells, with minimal expression in healthy cells. Tarlatamab has already established a significant lead over its competitors, and with the potential success of DeLLphi-301, it could be the first in the DLL3 market.”

The Phase II DeLLphi-301 trial focused on patients with SCLC undergoing two prior treatment regimens. It aimed to assess two doses, 10mg and 100mg, in alignment with the FDA’s Project Optimus initiative for dose optimization in oncology drug development. The 10mg dose of tarlatamab resulted in a notable 40% ORR, whereas the 100mg dose had a lower ORR of 32%. Notably, the 10mg dose also showed a longer median PFS of 4.9 months compared to 3.9 months in the 100mg dose group. Patients diagnosed with this advanced stage of the disease have a mere 6% three-year survival rate.

Morina continues, “Despite the passage of time, treatment options for SCLC have seen minimal advancements and remain limited, thus these results imply that tarlatamab may have a huge impact for such patients.”

One major hurdle is the drug’s safety profile, as one patient in the 10mg group succumbed to respiratory failure, an outcome that the investigators attributed to a potential association with tarlatamab.

Morina concludes, “This may impact the drug’s initial uptake until physician familiarity and its safety outcomes are evinced in clinical practice over time. Despite this, tarlatamab does have the upper hand and, if approved, is expected to have considerable dominance in the SCLC market by being the first validated instance of targeting DLL3/CD3 in the clinic.”