Immunotherapy Pembrolizumab Receives FDA Approval for 3rd-Line Treatment of Small Cell Lung Cancer

On June 17, 2019, the United States Food and Drug Administration (FDA) granted accelerated approval to pembrolizumab (Keytruda), an immunotherapy drug, for patients with metastatic (stage 4) small cell lung cancer (SCLC), who had received platinum -based chemotherapy followed by at least one additional line of treatment, for 3rd-line treatment.

Which Studies Led to FDA Approval of Pembrolizumab in Small Cell Lung Cancer?

• Pembrolizumab's effectiveness was investigated in 83 patients with small cell lung cancer who had received at least 2 prior lines of treatment and were enrolled in one of two multicenter, multicohort, nonrandomized, open-label studies: KEYNOTE-158 Cohort G and KEYNOTE-028 Cohort C1.
• Patients received either intravenous (into a vein) 200 mg every 3 weeks (64 patients) or intravenous 10 mg/kg every 2 weeks (19 patients) of pembrolizumab .
• Immunotherapy treatmentcontinued for a maximum of 24 months until documented disease progression or unacceptable side effects developed.

Results

• The main efficacy outcome measures were objective response rate to treatment and duration of response.
• Of the patients, 19%had an objective response to treatment; the complete response rate was 2% .
• For the 16 patients who responded, the response lasted: - 6 months or longer in 94%, - 12 months or longer in 63%, - 18 months or longer in 56%.

Side Effects

• Side effects in patients receiving single-agent pembrolizumab for previously treated small cell lung cancer were similar to those in patients receiving pembrolizumab for other solid (organ) tumors.
• Common side effects reported in at least 20% of patients included
• fatigue,
• loss of appetite,
• cough,
• nausea and
• constipation .
• Pembrolizumab was discontinued because of side effects in 9% of patients, and at least 1 dose was withheld because of side effects in 25%.
• Serious (grade 3 and 4) side effects occurred in 31% of patients.
• The most frequent (≥2%) serious side effects were pneumonia and pleural effusion (fluid accumulation between the membranes surrounding the lungs).

Recommended Dose

The recommended pembrolizumab dose for small cell lung cancer is 200 mg as an intravenous infusion over 30 minutes until disease progression or unacceptable toxicity/side effects, or for up to 24 months in patients without disease progression.

More Information About Pembrolizumab

Pembrolizumab was first approved for metastatic melanoma in 2014 and has since been used for non-small cell lung cancer, head and neck squamous cell cancer, classical Hodgkin lymphoma, primary mediastinal large B-cell lymphoma, urothelial carcinoma, microsatellite instability-high solid cancers, gastric cancer, cervical cancer, hepatocellular carcinoma, Merkel cell carcinoma and renal cell carcinoma, for which it received FDA approval.