Amarin Corp plc's shares soared on positive clinical developments Monday, but bullish option positions in the name rose much farther.

On August 27, Investitute's proprietary programs found that 4,000 Weekly $4.50 calls expiring on October 5 were purchased for $0.58 to $0.65 with shares at $2.87. There was no open interest in the strike before that session began, showing that this was fresh buying.

Medical trials can lead to significant profits or heartfelt losses for investors. These investors may have purchased these upside calls to reflect their belief that the shares of AMRN would appreciate significantly on the back of positive news, but only wished to risk 22.6% of the cost of the underlying equity at their time of purchase, greatly limiting their risk.

Those Weekly 05 October $4.50 calls traded for $7.92 Monday, more than 12 times their purchase prices. The stock surged more than fourfold in the same time frame, a huge move but still far below that of its options on a relative basis.

Long calls lock in the price where investors can buy a stock, letting them position for a rally at limited cost with the potential for significant leverage. They carry less risk than owning shares because the most that can be lost is the price of the options no matter how far the stock might fall.

Amarin rocketed 314.72% to $12.40 on Monday, September 24. Shares soared that morning after the biopharmaceutical company said its Vascepa cholesterol treatment significantly reduced heart problems in tests.