Insmed's stock soared 9.80% during intraday trading on Tuesday, marking a significant rebound from recent declines.

The surge follows RBC Capital Markets' defense of the stock, stating that the post-Q1 earnings sell-off was overdone. RBC maintained its full-year 2026 Brinsupri sales guidance of approximately $1.3 billion and kept its Outperform rating, noting that organic patient additions should enable the non-cystic fibrosis bronchiectasis treatment to clear the $1 billion threshold with cushion.

Insmed's first-quarter results actually beat expectations, with net product revenue of $306 million versus estimates of $300.8 million and an EPS loss of $0.76 versus the estimated loss of $0.97. Despite the earnings beat, the stock had initially sold off on investor concerns about patient addition trends and compliance rates before RBC's analysis prompted the rebound.