The standard of care for small-cell lung cancer (SCLC ) was unchanged for over 20 years, with platinum-based chemotherapy being the treatment of choice for extensive-stage (ES) disease. In 2018, the approval of Bristol-Myers Squibb ’s Opdivo (nivolumab) in the second-line setting marked the beginning of the immunotherapy era for ES-SCLC.

Subsequently, the US food and drug administration (FDA) approved Genentech’s Tecentriq (atezolizumab) in combination with chemotherapy as a first-line treatment for ES-SCLC based on a 30% reduction in risk of death observed in the phase three IMpower133 trial. This approval established Tecentriq as the standard of care and transformed the treatment paradigm by including immunotherapy agents in both the first and second line.

In June 2019, Merck ’s Keytruda (pembrolizumab) also received FDA approval as single agent for the treatment of patients who had progressed on more than one other lines of therapy, claiming a share of the second-line market.

AstraZeneca ’s Imfinzi (durvalumab) received priority review status by the FDA in November 2019 for the first-line treatment of ES-SCLC in combination with chemotherapy based on data from the phase three CASPIAN trial showing a 27% reduction in the risk of death.

PharmaMar’s lurbinectedin received priority review in February 2020 for the treatment of patients who progressed on previous platinum therapy based on data from a single-arm phase two study showing an overall response rate (ORR ) of 35.2%. Historically, this compares favourably with Keytruda’s 19% ORR.

With platinum chemotherapy still being used upfront, GlobalData expects that Keytruda and lurbinectedin will both have an important role to play in patients who progress on chemotherapy. Therefore, it is probable that two new branded agents will enter the SCLC market during 2020, eroding away any remaining share from second-line chemotherapy.

This will bring the number of new, premium-priced agents available in 2020 to five, with clear implications for the value of this market. GlobalData estimates that as many as 17,000 newly diagnosed ES-SCLC patients in the US could be eligible to receive Tecentriq or Imfinzi. Previously these patients would have been treated with chemotherapy. Keytruda, Nivolumab and lurbinectedin may be available to a similar number of patients progressing from previous therapy.

GlobalData also estimates that the current SCLC US market value has crossed the $1bn mark and that, with a number of ongoing label expansion trials for patients with limited-stage disease, this figure will only increase.