Shares of Allakos Inc. /zigman2/quotes/203639566/composite ALLK -0.40% rallied 37% in afternoon trading, to a record high. Sources told Bloomberg that the Redwood, Calif.-based biopharmaceutical company, which went public in August, is considering a sale. Allakos is in the early stages of developing treatments for eosinophilic gastritis and allergic conjunctivitis, among others. The rally has added roughly $1.7 billion to the company's market capitalization, to boost the market cap to about $6.4 billion. The company has not immediately responded to a request for comment. Allakos stock is up 146% year-to-date. The S&P 500 /zigman2/quotes/210599714/realtime SPX +1.05% has gained 24%.