Something is happening with Corbus Pharmaceuticals Holdings, Inc. (NASDAQ:CRBP). Since February, the stock has risen 600%, 158% since August alone. Not only that, but trading volume has exploded to the upside, particularly on Friday when the stock reached a peak of $7.88 on volume over 7.5x the average. What is behind the surge, and can it be sustained?

The two questions are separate issues, but the answer to the first could give us clues as to the second. As for catalysts, it seems to be a combination of three things. First, a surge in institutional ownership since July. Second, continued insider buys by executive staff. Third and most recently, the completion of enrollment in its critical Resunab Phase II trial for cystic fibrosis.

That the trial has completed enrollment sets in stone the countdown to top-line results. Companies may issue plans, make statements about what they intend, give their best guesses and try to sound optimistic when communicating with shareholders about when data will be reported. Once enrollment is complete though, investors know that it will actually happen. According to the press release, the last patient was enrolled on or around September 12, and each CF patient is treated with Resunab of 84 days with a 28 day follow up. That’s a total of 112 days from enrollment, which puts the date of final data collection at or around January 2, 2017. Allowing time for procedural maneuvers whatever they may be, results should be made public by the end of January.

This is on top of another Phase II trial of the same drug for systemic sclerosis. Enrollment for that trial was completed on June 16, also with the same treatment regime of 84 days plus 28 days follow up. That pins systemic sclerosis top line data for release on or around October 6. That’s less than 3 weeks away. Again accounting for any possible procedural issues, data should be public by the end of October or early November at the latest.

The fact that both of these trials are fully enrolled and set to release data within weeks of each other may have itself been the catalyst for the spate of institutional and insider buying since July.

The interesting part is that the success of the first trial could imply the success of the second. In both cases, the company is targeting the inflammatory response, which Resunab is designed to counter as one of the most powerful anti-inflammatories currently known to exist. For systemic sclerosis, the idea is that by stopping inflammation, you stop the symptoms of the disease which is characterized by autoimmune inflammation in the skin that worsens over time and eventually spreads to the organs.

If it works with systemic sclerosis, it should in theory also work with cystic fibrosis. The case with CF is a little different because the disease is not caused by inflammation, but only exacerbated by it. Since the lungs cannot clear out phlegm in CF sufferers, this triggers the inflammatory response, which only makes matters worse. This starts a vicious cycle of inflammation that causes fibrosis in the lungs, hence the disease’s name. Stop the inflammation, slow down the fibrosis, and the lungs are strengthened, or so goes the theory.

From a technical standpoint, the stock is overbought. The RSI is through the roof, the stock has not closed down on the daily charts for 11 days in a row, and shares have never been in this territory. The nearest support level is at $5. So just looking at the technicals, the rally doesn’t seem sustainable. But from a fundamental standpoint, considering that top-line data for systemic sclerosis could be available less than three weeks from now, and that this data will have strong implications for the cystic fibrosis trial, then even if shares fall to support at $5 on simple profit-taking, positive top-line data should bring shares back up to their highs at $7.88.

In short, the catalysts are a combination of completed enrollment, and institutional together with insider buying. Whether the rally is sustainable beyond October relies almost entirely on the upcoming Phase II systemic sclerosis data, and then on the cystic fibrosis data into 2017.

Disclosure: The author was long CRBP at time of writing.