After yesterday's explosive session, the Mesoblast Ltd (ASX: MSB) share price is retreating today.

As we tip past midday, shares in the clinical-stage drug developer are down 10% to 85.5 cents apiece. The move paints a vastly different scene from what was portrayed yesterday, with the Mesoblast share price blazing 71% higher as $58.4 million worth of shares changed hands.

Here's a refresher if you're wondering what's behind this heightened volatility.

Back in August last year, the Mesoblast share price suffered a crippling blow.

The US Food and Drug Administration (FDA) informed the company that it required more data to support marketing approval for remestemcel-L to treat pediatric steroid-refractory acute graft versus host disease (SR-aGVHD).

The consequence of this outcome on Mesoblast shares is patently clear on a 1-year price chart, as shown below. Shares quickly caved from $1.09 to 38 cents in a week, erasing almost $600 million of market capitalisation in the process.

The setback prompted Mesoblast to raise $97 million of capital at a time when it would be most dilutive (due to the reduced share price). To say the past eight months, or thereabouts, have been a harrowing time for Mesoblast investors would be putting it lightly.

However, last week produced a spark of hope. The FDA informed Mesoblast that its phase 3 study data now appeared adequate for submission of its Biologics License Application (BLA). In turn, management is confident in refiling its application for remestemcel-L in children with SR-aGVHD.

Mesoblast aims to submit its application to the FDA in the next quarter.

The turnaround corresponds with a 177% rise in the Mesoblast share price this year. With shares trading 10.5% lower today, there's a possibility shareholders are taking some profits off the table.

The S&P/ASX 300 Index (ASX: XKO) is the baseline for outperformance. As of today, the index is up 2.4% year-to-date, which means Mesoblast has beaten the benchmark by a staggering 174.6% in 2024.

But what about when compared to the top-performing ASX 300 shares?

Well, as it turns out, Mesoblast is also the top of that bunch. The next closest is Zip Co Ltd (ASX: ZIP), with its sizeable 107% gain this year.