FDA Approves Durvalumab as the First and Only Immunotherapy for LSSC Lung Cancer

The US Food and Drug Administration (FDA) has approved Durvalumab (Imfinzi) as the first and only immunotherapy for adult patients with limited-stage small cell lung cancer (LS-SCLC) following chemotherapy and radiation therapy. The ADRIATIC Phase III trial showed Imfinzi reduced death risk by 27%, with a median overall survival of 55.9 months, and 57% of patients alive at three years.

Developed by AstraZeneca, durvalumab marks a pivotal milestone in the treatment of this aggressive cancer, known for its high recurrence rates and poor prognosis.

The Approval Based on ADRIATIC Trial Results

The approval, granted under the FDA’s Priority Review and Breakthrough Therapy Designation, is based on findings from the ADRIATIC Phase III trial. Presented at the 2024 ASCO Annual Meeting and published in the New England Journal of Medicine, the trial highlights significant improvements in patient survival outcomes with Imfinzi.

“Durvalumab is the first and only systemic treatment following curative-intent, platinum-based chemoradiotherapy to show improved survival. This finding represents the first advance for this disease in four decades. The ADRIATIC trial showed 57 percent 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,” said Dr. Suresh Senan, Professor of Clinical Experimental Radiotherapy at Amsterdam University Medical Centers and the trial’s international coordinating investigator.  

Key findings from the ADRIATIC trial include:

• Overall Survival (OS): Imfinzi reduced the risk of death by 27% compared to placebo (HR: 0.73; p=0.0104). The median OS for patients treated with Imfinzi was 55.9 months, compared to 33.4 months for the placebo group.
• Progression-Free Survival (PFS): Imfinzi reduced the risk of disease progression or death by 24% (HR: 0.76; p=0.0161). Median PFS was 16.6 months for Imfinzi, versus 9.2 months for placebo.
• The results underscore a practice-changing potential: 57% of patients treated with Imfinzi were alive at three years, compared to 48% for placebo.

A Long-Awaited Breakthrough in LS-SCLC

For over four decades, treatment advancements in LS-SCLC have been elusive. Currently, only 15-30% of patients survive five years post-diagnosis. Durvalumab offers new hope as the first systemic therapy to improve survival following curative-intent chemoradiotherapy.

Dave Fredrickson, Executive Vice President, Oncology Business Unit, AstraZeneca, said: “The ADRIATIC trial showed an improvement in median overall survival of 22.5 months, setting a new benchmark. Imfinzi is now the only immunotherapy approved for both limited- and extensive-stage small cell lung cancer, underscoring our commitment to improving survival rates.”

Safety and Administration

The safety profile of DurvalumabThe ADRIATIC trial showed an  was consistent with previous findings. Common adverse reactions include pneumonitis or radiation pneumonitis and fatigue. Imfinzi is administered at a fixed dose of 1,500 mg every four weeks for patients weighing ≥30 kg, for up to 24 months or until disease progression or unacceptable toxicity.

Dusty Donaldson, Founder and Executive Director of LiveLung, expressed optimism about the approval. “This new treatment option is a game changer for patients with limited-stage small cell lung cancer, a disease known for its high rate of recurrence. Historically, 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.”

Global Collaboration and Regulatory Efforts

The review was conducted under Project Orbis, an FDA initiative for simultaneous oncology drug reviews among international partners. In this instance, the FDA collaborated with regulatory bodies in Australia, Brazil, Canada, and Switzerland, while the European Medicines Agency served as an observer. Imfinzi has already been approved in Switzerland for LS-SCLC based on ADRIATIC data, and regulatory reviews are underway in the EU, Japan, and other countries.