ASCO 2016 Highlight: New Antibody Drug Shows Early Promise In Small Cell Lung Cancer

ASCO Perspective

“This is another example of a new wave of highly targeted treatments, which deliver anticancer drugs even more precisely to where they are needed,” said Gregory Masters, MD, FACP, FASCO, ASCO Expert in lung cancer. “These results mark a good, early sign of success against a cancer for which we urgently need better therapy options.”

Early findings from a first-in-human clinical trial showed that antibody drug conjugate (ADC) rovalpituzumab tesirine (Rova-T) shows promising efficacy against recurrent small cell lung cancer (SCLC). The treatment, which combines a novel anti-DLL3 antibody with a powerful anticancer agent, halted tumor growth in 89% of patients with high levels of DLL3 in the tumor and shrank tumors in 39%.

The study will be featured in a press briefing today and presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.

“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,” said lead study author Charles M. Rudin, MD, PhD, a medical oncologist and chief of Thoracic Oncology Service at Memorial Sloan Kettering Cancer Center in New York. “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.”

About the Study

The ADC rovalpituzumab tesirine comprises an anti-DLL3 antibody and a cancer-killing agent, pyrrolobenzodiazepine dimer, which damages DNA. The antibody component of the ADC serves to deliver the anticancer agent to the tumor and into cancer cells.

Approximately two-thirds of patients with SCLC have high-level DLL3 on the surface of cancer cells, and the protein is essentially absent from healthy adult tissues. DLL3 is known to regulate cancer stem cell biology in SCLC. Rovalpituzumab tesirine is the first agent to target DLL3.

The Phase I study enrolled 74 patients with SCLC that worsened despite at least one prior systemic therapy. About two-thirds of patients had extensive-stage disease at diagnosis, and the other third had limited-stage disease. When tissue samples were available, the researchers assessed levels of DLL3 protein in the tumor tissue.