What happened, in summary

A 34-year-old woman who had never smoked presented with cough, shortness of breath and large pleural and pericardial effusions. Biopsy confirmed lung adenocarcinoma, and imaging showed pleural and pericardial metastatic disease, making this Stage IV cancer. Molecular testing identified the rare BRAF exon 15 p.T599dup alteration, and PD-L1 expression was 5%. She started dabrafenib plus trametinib and improved quickly, with stable disease after the first month. Recurrent pericardial effusion later required drainage and the addition of bevacizumab. After 8 months, new lung nodules and increasing pericardial fluid showed progression. She switched to pemetrexed, carboplatin, pembrolizumab and bevacizumab, then continued maintenance pemetrexed, pembrolizumab and bevacizumab. The second-line regimen produced a partial response that was still ongoing about 1 year after the treatment change.