ASCO16: Antibody drug conjugate demonstrates promising efficacy in small-cell lung cancer patients

A first-in-human clinical trial has reported promising efficacy for an antibody drug conjugate, rovalpituzumab tesirine, in small-cell lung cancer (SCLC) patients. The study was presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting (3–7 June 2016, Chicago, USA) by lead study author Charles Rudin from the Memorial Sloan Kettering Cancer Center (NY, USA).

Rudin and his team enrolled 74 SCLC patients into a Phase I study. Of the 60 evaluable patients, 41 patients (68%) demonstrated clinical benefit and eleven (18%) experienced tumor shrinkage.  The group also reported promising results in patients who expressed over 50% DLL3, with 39% of these patients responding well to the antibody drug conjugate.  Among all SCLC patients, the most common treatment-related toxicities observed were serosal effusion (14%), thrombocytopenia (12%) and skin reaction (8%); the group observed that these toxicities were generally manageable with medication.

Speaking about the study, Rudin commented: “We’ve seen too few successes in recent years for small cell lung cancer, which makes these early signs of efficacy all the more encouraging. Although these results are preliminary, rovalpituzumab tesirine seems to be the first targeted therapy to show efficacy in small cell lung cancer, and we may have identified DLL3 as the first predictive biomarker in this disease.”

“Importantly, this is the first biomarker-directed therapy to be defined for the treatment of SCLC, and as this is a biomarker that is expressed in a large majority of SCLC, it may have a lot of utility in the management of these patients,” Rudin concluded.

The group plan to confirm their preliminary findings through larger clinical trials that will assess rovalpituzumab tesirine in first line SCLC in addition to a single-arm pivotal study in 3rd line DLL3-expressing SCLC tumours.