More patients with advanced non-small-cell lung cancer (NSCLC) could benefit from pembrolizumab, says Professor Roy Herbst, Chief of Medical Oncology, Yale Cancer Center and Smilow Cancer Hospital at Yale-New Haven, presenting promising results from the pivotal phase 2/3 KEYNOTE-010 trial at the first ESMO Asia Congress in Singapore, in conjunction with a publication in The Lancet. 

The study shows that two doses of the anti-PD-1 antibody pembrolizumab, the US Food and Drug Administration (FDA)-approved 2 mg/kg dose and an investigational 10 mg/kg dose, each given every 3 weeks, improve median survival in all PD-L1-positive patients compared with the commonly used chemotherapeutic agent docetaxel.

The benefit is even greater in the group of patients with PD-L1 staining in ≥50% of tumour cells.

Pembrolizumab has demonstrated clinical activity in multiple tumour types, including benefit over standard-of-care therapy in melanoma and lung cancer.

By blocking the PD-1/PD-L1 pathway, which has a crucial role in neoplastic growth when activated, the drug has shown its durable antitumour activity and acceptable toxicity in treatment-naive and previously treated advanced NSCLC patients.

The open-label KEYNOTE-010 is the first study to assess the benefits of immunotherapy as second- or later line in patients with refractory lung cancer selected for PD-L1 expression.

From August 2013 to April 2015, 1034 patients with advanced NSCLC from 24 countries (EU nations, US and Asia, including Japan, South Korea and Taiwan) were randomised to pembrolizumab (2 mg/kg or 10 mg/kg) or docetaxel.

All patients had experienced disease progression after platinum-containing systemic therapy and were stratified by PD-L1 expression level (tumour proportion score, TPS ≥50% vs 1-49%).

“The topline results show that both groups of patients receiving pembrolizumab experience a survival benefit compared to docetaxel,” Herbst said.

“As expected, at the highest biomarker expression, the results were even better with a hazard ratio (HR) of 0.54 and 0.50 at the two doses of pembrolizumab, respectively. Treatment with pembrolizumab was associated with longer overall survival (OS) compared to docetaxel (median 14.9 and 17.3 months with 2 mg/kg and 10 mg/kg of pembrolizumab and 8.2 months with docetaxel).

“We additionally observed a quite clear benefit in patients who expressed >1% PD-L1 positivity in the tumour, with hazard ratios for OS of 0.71 and 0.61 in the pembrolizumab arms (at 2 mg/kg and 10 mg/kg, respectively). These results give further support for broadening the availability of pembrolizumab for all patients with PD-L1 expression over 1%.”

In this trial, the safety profile of pembrolizumab was consistent with that from previous NSCLC studies.

“Data from KEYNOTE-010 further supports the efficacy, safety and tolerability of pembrolizumab in patients with advanced stage NSCLC,” Dr Ross Soo, Adjunct Principal Investigator, Cancer Science Institute of Singapore, who was not involved in the study, said.

“The drug is not yet approved in Asia and in Europe, and this study could help in this direction.”

This year, another drug targeting the PD-1/PD-L1 pathway, nivolumab, received approval for the treatment of advanced-stage NSCLC without any required biomarker selection of patients.

“The hazard ratio for overall survival favours pembrolizumab as compared with the recently approved second-line treatment options in advanced stage NSCLC such as docetaxel plus ramucirumab or docetaxel plus nintedanib,” Soo said.

“However, cross-trial comparisons should be interpreted with caution. In the absence of a direct head-to-head comparison, the choice of the specific PD-1 inhibitor relies on different factors such as costs of treatment, scheduling, and availability of biomarker testing.”

Future studies are needed to assess whether patients who express PD-L1 in less than 1% of tumour cells would have some benefits from pembrolizumab.

“Data from the KEYNOTE-010 study suggests, that pembrolizumab would be given to all patients with PD-L1 expression and this could have an impact on current strategies for lung cancer,” Herbst concluded.

“I believe we should use the best available weapons first. Now that we have learned which patients are most likely to benefit from the anti-PD-L1 strategy, we could start to move this weapon to the earlier stages. In this direction, I am eager to see the results of ongoing studies testing pembrolizumab in the first-line setting and eventually prevent the recurrence of lung cancer which is still at high rates.”

Reference

Herbst, Baas, Kim et al. (2015) Pembrolizumab versus docetaxel for previously treated, PD-L1-positive, advanced non-small-cell lung cancer (KEYNOTE-010): a randomised controlled trial, The Lancet, published Online: 19 December 2015

Source: ESMO