First-line osimertinib proved effective in patients with non-small cell lung cancer (NSCLC) aged 75 years and older but was associated with a high rate of pneumonitis, according to research published in Scientific Reports.

“[T]he high frequency of pneumonitis, which was associated with poor prognosis, is a serious concern,” the researchers wrote.

They conducted this real-world study to evaluate clinical outcomes in patients age 75 years or older with advanced, EGFR-mutant NSCLC who received first-line osimertinib.

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The retrospective study included 132 patients with a median age of 80 years (range, 75-90 years). There were 93 patients (70.5%) with stage IV NSCLC, 92 (69.7%) never-smokers, and 34 (25.8%) with a postoperative or post-radiotherapy recurrence.

Regarding EGFR mutations, 46 patients had exon 19 deletions, 80 had exon 21 L858R mutations, and 1 patient had both an exon 19 deletion and L858R mutation. Five patients had uncommon mutations, including G719X, L861Q, and exon 20 insertions.


In the 113 patients with measurable lesions, the overall response rate was 75.2%, and the disease control rate was 92.9%. Three patients had a complete response, 82 had a partial response, 20 had stable disease, and 2 had progressive disease.

At a median follow-up of 20.5 months, the 1-year progression-free survival (PFS) rate was 65.8%. The median PFS was 19.4 months, the median time to treatment failure was 17.7 months, and the median overall survival (OS) was not reached.

Adverse events (AEs) of grade 3 or higher occurred in 41.7% of patients. The most common AEs were paronychia (43.9%), rash or acne (39.4%), dry skin (38.6%), and anemia (38.6%).

The rate of any-grade pneumonitis was 17.4%, and the rate of grade 3 of higher pneumonitis was 9.1%.

Treatment was discontinued in 35 patients, with pneumonitis being the most common cause of discontinuation. A majority (70%) of treatment discontinuations due to pneumonitis occurred within 3 months of starting osimertinib.

The median PFS was 7.9 months in patients who developed any-grade pneumonitis and 21.2 months in patients without pneumonitis. The median OS was 15.8 months and not reached, respectively. 

There were 4 treatment-related deaths — 3 due to pneumonitis and 1 due to heart failure.

“Osimertinib is one of the effective first-line therapeutic options for patients aged 75 years or older; however, special caution should be exercised due to the potential development of pneumonitis,” the researchers wrote. “Further large prospective studies are needed to assess the association of drug-related toxicities, especially pneumonitis, and baseline clinical characteristics.”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


Yamamoto G, Asahina H, Honjo O, et al. First‑line osimertinib in elderly patients with epidermal growth factor receptor‑mutated advanced non‑small cell lung cancer: A retrospective multicenter study (HOT2002). Sci Rep. Published online November 30, 2021. doi:10.1038/s41598-021-02561-z

This article originally appeared on Cancer Therapy Advisor