Extensive-stage small-cell lung cancer with bone metastases: stable response after durvalumab rechallenge

What happened, in summary

This 66-year-old woman presented in August 2021 with sudden bone pain involving the skull, neck, and lower back. CT, SPECT, bone scans, and spine MRI showed lung nodules and diffuse bone lesions along the axial skeleton and skull. Lung biopsy confirmed extensive-stage small cell lung cancer. Because of concern for bony instability and possible spinal cord involvement, she received palliative external-beam radiation to the skull and spine in November 2021. In December 2021, she started carboplatin, etoposide, and durvalumab, given every 3 weeks for 4 cycles. After induction chemoimmunotherapy ended in March 2022, she continued maintenance durvalumab 1500 mg IV every 4 weeks, with surveillance imaging showing stable disease. In February 2024, after about 23 months of treatment, she developed recurrent abdominal and epigastric pain, appetite loss, cramping, and weight loss of about 11.8 kg. Durvalumab was held. Endoscopy showed diffuse gastritis, and symptoms resolved after prednisone 20 mg daily for 1 week followed by a slow taper. Durvalumab was restarted on June 19, 2024, with prednisone 5 mg daily for 4 days around each cycle to prevent recurrence. As of November 2025, she remained on durvalumab, had no recurrence of significant gastritis symptoms, and had continued treatment response without disease progression. She had been independent and working at diagnosis, with ECOG performance status 0, despite comorbid hypertension, COPD, controlled GERD, coronary artery disease, and sigmoid diverticular disease. During the gastritis episode, antacids, milk of magnesia, an H2 blocker, and a proton pump inhibitor were tried before steroids. After the rechallenge, only mild GI symptoms recurred and resolved spontaneously.