Earnings season is winding down, with most companies already having reported their quarterly results. But there are still some companies left to report, and Peregrine Pharmaceuticals (NASDAQ: PPHM) is about to release its quarterly earnings. The key to making smart investment decisions with stocks releasing their quarterly reports is to anticipate how they'll do before they announce results, leaving you fully prepared to respond quickly to whatever inevitable surprises arise. That way, you'll be less likely to make an uninformed knee-jerk reaction to news that turns out to be exactly the wrong move.

Peregrine Pharmaceuticals is one of many small biotech companies still looking to get their first drugs approved. Despite having very little in the way of revenue, the company has had a lot happening with it lately. Let's take an early look at what's been happening with Peregrine Pharmaceuticals over the past quarter and what we're likely to see in its quarterly report on Tuesday.

Stats on Peregrine Pharmaceuticals

Analyst EPS Estimate

($0.07)

Year-Ago EPS

($0.13)

Revenue Estimate

$3.9 million

Change From Year-Ago Revenue

19%

Earnings Beats in Past 4 Quarters

3

Source: Yahoo! Finance.

What's been happening with Peregrine Pharmaceuticals this quarter?
Analysts have raised their estimates slightly on Peregrine over the past few months, reducing their loss expectations by a penny per share for the just-ended quarter and by $0.03 per share for the full 2013 fiscal year. The stock has reflected even more optimism, rising nearly 30% since early December, but having given back much bigger gains from earlier this year.

Lately, investors have been on a roller-coaster ride with Peregrine's stock. Last September, the company said that its own favorable clinical trial results for its most promising pipeline cancer drug, bavituximab, weren't trustworthy, sending the shares down 80%. Yet by November, investors were getting more confident about the stock, seeing that mistakes made in the trial didn't necessarily mean the drug didn't work.

Then, in January, Peregrine said its third-party vendor had only mixed up part of its trial data, drawing favorable conclusions from the accurate part of the trial. Yet without explicit statistical analysis of the results, it's hard for investors to compare bavituximab's effectiveness against Celgene's (CELG) rival pancreatic-cancer drug Abraxane.

In its earnings report, Peregrine needs to be as forthcoming about the bavituximab trial, providing as much statistical analysis as possible to help support its assertions that the drug has good prospects. Without that, it's hard to see investors regaining confidence in the stock over the long haul.

Click here to add Peregrine Pharmaceuticals to My Watchlist, which can find all of our Foolish analysis on it and all your other stocks.