Maxim analyst Jason Kolbert reiterates a Buy rating on shares of Mast Therapeutics Inc (NYSEMKT:MSTX) following an announcement of first patient enrollment in the phase II study for pipeline drug, AIR001, an inhaled nebulized sodium nitrite designed to treat heart failure with preserved ejection fraction (hFpEF). Kolbert indicates a price target of $5.00, marking a substantial 1,308% increase from where the stock is currently trading.

For the analyst, phase II data proved promising, as “AIR001 demonstrated a statistically significant improvement in primary capillary wedge pressure (PCWP) and an invasive exercise stress test, as well as multiple secondary endpoints.” Though Kolbert takes this in favorable stride for the biotech leader, the analyst keeps his eyes peeled to September, when critical Sickle Cell Disease data will be released. Whether this stock will rise or fall depends upon these impending results. Kolbert notes having a “positive skew,” recognizing this SCD data “as the key event that will impact the stock.”

Until then, Kolbert’s optimism can also be attributed to Mast’s advance with pipeline drugs like AIR001 and vepoloxamer (expected to be approved and launched in the United States by 2017, followed by a European launch by 2018) seeing support from the Heart Failure Network, Mayo Clinic, and National Heart and Lung Blood Institute. This support finds Kolbert feeling validated in his optimism, although he does acknowledge he expects no major impact upon capital on the heels of this support.

According to TipRanks, which measures analysts’ and bloggers’ success rate based on how their calls perform, Jason Kolbert is ranked #4,004 out of 4,085 analysts. Kolbert’s success rate to date stands at 29%, averaging a loss of 14% in his annual returns.

TipRanks analytics demonstrates Mast Therapeutics stock is a Strong Buy. Of the 3 analysts who have offered ratings for MSTX the past 3 months, 100% of them rate a Buy. The 12-month average price target is $3.33, marking a significant 851% upside from where shares last closed.

Read More: Roth Capital Remains Bullish on Mast Therapeutics Inc (MSTX); Says Market Overreacting to Brief Delay in EPIC Top-Line Data »