NEW YORK (TheStreet) -- Gilead Sciences (GILD) - Get Report shares closed trading down 1.74% to $100.51 on Monday after the pharmaceutical company warned of a potentially fatal complication for patients being treated with its hepatitis C treatments Harvoni or Sovaldi.

Gilead said that it sent an email to healthcare service providers warning them that it had witnessed nine cases of treating patients with Harvoni or Sovaldi while also taking amiodarone resulting in irregular heartbeats and one case that resulted in death.

Sovaldi had sales of $1.7 billion alone during the fourth quarter while a combination treatment regiment featuring Harvoni combined with Sovaldi brought in another $2.1 billion for Gilead in the quarter.

Gilead shares have rallied slightly in after-hours trading, rising 0.22% to $100.48 today.

Separately, TheStreet Ratings team rates GILEAD SCIENCES INC as a Buy with a ratings score of A. TheStreet Ratings Team has this to say about their recommendation:

"We rate GILEAD SCIENCES INC (GILD) a BUY. This is based on the convergence of positive investment measures, which should help this stock outperform the majority of stocks that we rate. The company's strengths can be seen in multiple areas, such as its robust revenue growth, solid stock price performance, impressive record of earnings per share growth, compelling growth in net income and notable return on equity. Although no company is perfect, currently we do not see any significant weaknesses which are likely to detract from the generally positive outlook."

Highlights from the analysis by TheStreet Ratings Team goes as follows:

• You can view the full analysis from the report here: GILD Ratings Report

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