FDA clears AZ's Imfinzi for aggressive lung cancer

AstraZeneca's PD-L1 inhibitor Imfinzi has become the immunotherapy to be approved in the US for limited-stage small cell lung cancer (LS-SCLC), a particularly challenging form of the disease.

Imfinzi (durvalumab) has been given the green light for the treatment of adults with LS-SCLC whose disease has not progressed after concurrent platinum-based chemotherapy and radiation therapy (CRT) on the back of positive results in the ADRIATIC study reported earlier this year.

SCLC is less common than non-small cell lung cancer (NSCLC), making up around 15% of all lung cancer cases. Around 30% of SCLC diagnoses come when the tumour is confined to one lung or one side of the chest, defining it as LS-SCLC.

This form of the disease can be cured in some patients with first-line CRT but, despite that, only around a quarter of patients live beyond five years.

In ADRIATIC, Imfinzi achieved a statistically significant improvement in both progression-free survival (PFS) and overall survival (OS) compared to placebo when used in the second-line setting.

The results – which were published in the New England Journal of Medicine (NEJM) in September – showed that Imfinzi extended the median survival time for patients from 33.4 months with placebo to 55.9 months, a 27% improvement.

Similarly, Imfinzi also reduced the risk of disease progression or death by 24%, with the median PFS 16.6 months versus 9.2 months in the control group.

Imfinzi is the first advance in treatment for LS-SCLC in nearly four decades, according to ADRIATIC investigator Suresh Senan of Amsterdam University Medical Centers in the Netherlands.

"The ADRIATIC trial showed 57% of patients were still alive at three years after being treated with durvalumab, which underscores the practice-changing potential of this medicine in this setting," he remarked.

Imfinzi is already approved for extensive-stage SCLC based on the results of the CASPIAN trial, as well as for locally advanced NSCLC that can't be treated with surgery and has not progressed after CRT and alongside chemo in metastatic NSCLC.

AZ had a disappointment with the drug in the PACIFIC-2 clinical trial in locally advanced NSCLC that can't be treated with surgery and has not progressed after CRT, however, denting the company's plan to make Imfinzi an option for more than half of all lung cancer patients by 2030.

The new approval in LS-SCLC has been welcomed by patient organisation LiveLung, which called Imfinzi a "game-changer."

Founder and executive director Dusty Donaldson said that "more often than not, clinical trials to identify new treatment options for this type of cancer have failed to show benefit."

"We are therefore so excited that many more people will now have the opportunity to access this immunotherapy treatment that holds the potential to significantly improve outcomes."