New Antibody Therapy Could Effectively Treat Small Cell Lung Cancer

Rovalpituzumab tesirine reduced tumor growth and even shrank tumors in some patients with small cell lung cancer.

Preliminary findings from a recent study suggests that the antibody drug conjugate (ADC) rovalpituzumab tesirine (Rova-T) could be effective in treating recurrent small cell lung cancer (SCLC).

The treatment combines an anti-DLL3 antibody with pyrrolobenzodiazepine dimer, an anticancer agent that damages DNA, according to a study presented at the 2016 American Society of Clinical Oncology Annual Meeting.

The antibody part of the ADC delivers pyrrolobenzodiazepine dimer to the tumor.

“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. “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.”

Approximately two-thirds of patients with SCLC have high levels of DLL3 on the surface of the cancer cells. DLL3 regulates cancer stem cells in SCLC and is not present in healthy adult tissues, according to the study.

The study included 74 patients with SCLC whose disease progressed regardless of prior systemic therapies. Researchers analyzed levels of DLL3 in tumor tissues when available. With the treatment, approximately 18% had tumor shrinkage and 68% achieved a stable disease state.

Researchers found that patients who responded to the treatment were more likely to have high levels of DLL3 in their tumor.

Approximately 39% of patients with the highest levels of DLL3 responded to the ADC. Their median overall survival was 5.8 months and these patients also had a 1-year survival of 32%.

In these patients, ADC treatment stopped tumor growth in 89% and shrank tumors in 39%. Researchers also found that 12 of the 26 patients with high levels of DLL3 who received ADC as third-line therapy responded well and 50% had tumor shrinkage, according to the study.

The most common adverse effects included serosal effusion, low platelet counts, and skin reactions.

Researchers state that these early findings will need to be confirmed in larger trials and in trials to evaluate rovalpituzumab tesirine in first line ACLC and other DLL3-expressing neuroendocrine cancers, the study concluded.