Merrimack Pharmaceuticals Inc (NASDAQ:MACK) shares shot up nearly 21% yesterday on back of August’s strong script data for ONIVYDE, the first approved anti-cancer treatment, which Symphony database released yesterday.

Despite the encouraging data, BTIG analyst Ling Wang believes it is too early to celebrate, even though the analyst deems the growth rate exhibited in August as “still very impressive at ~23%,” even in light of the fact August has three more business days at 23 than the month of July at 20. As such, Wang reiterates a Neutral rating on MACK without listing a price target.

Symphony posted August ONIVYDE gross sales at $6.1 million, which marks a 26% month-over-month growth outclassing July sales of $4.8 million.

“Since ONIVYDE is still fairly early in the launch period, one would expect month-to-month variations. Therefore, it is still challenging to predict the sales trajectory. Recall, MACK has recently taken actions to optimize the effort in marketing ONIVYDE. The strong growth in August could be a reflection of a combination of improved awareness and penetration of ONIVYDE, which may translate into new patients-add and longer treatment duration,” Wang concludes.

As usual, we recommend taking analyst notes with a grain of salt. According to TipRanks, analyst Ling Wang is ranked #4,066 out of 4,189 analysts. Wang has a 29% success rate and faces a loss of 18.2% in her yearly returns. When recommending MACK, Wang loses 42% in average profits on the stock.

TipRanks analytics demonstrate MACK as a Buy. Based on 5 analysts polled in the last 3 months, 2 rate a Buy on MACK, while 3 maintain a Hold. The consensus price target stands at $9.33, marking a nearly 52% upside from where the stock is currently trading.screen-shot-09-23-16-at-03-09-pm