Source: Celldex Therapeutics.

What: After reporting in its second-quarter earnings release a timeline for its brain cancer drug Rintega that could be longer than investors were hoping for, shares in Celldex Therapeutics (CLDX -1.43%) lost 37% of their value in August.

The significant slump in the company's shares may be presenting an opportunity for risk-tolerant investors to step in and buy.

So what: Celldex is a clinical stage biotech company that is developing cancer therapies. Because Celldex doesn't have any products on the market (yet), investors have been watching its pipeline closely.

Specifically, investors are tracking progress for Rintega, a drug for the tough-to-treat brain cancer known as glioblastoma. In May, Celldex offered up encouraging Rintega's mid stage phase 2 trial results showing that combining it with Avastin helped delay tumor growth, while also extending survival rates, and that led to optimism that Rintega could qualify for an accelerated timeline for approval.

However, those hopes appear dashed by Celldex's August revelation that discussions with regulators leave it believing that it will need to submit complete results from its phase 3 trial to win a regulatory green light.

Now what: There's a significant unmet need for new brain cancer therapies, but up to 40% of phase 3 trials fail and that could be why the FDA is approaching Rintega cautiously.

Regardless, the next Rintega interim analysis is expected either later this year or early in 2016, depending on the timing of evaluable events. Assuming that analysis results in a continuation of the trial, the phase 3 trial is slated to wrap up in November 2016.

If Rintega's late-stage trial does confirm positive results from earlier trials, then it could become part of a standard of care for the 10,000 to 12,000 new patients diagnosed with this aggressive cancer every year, but Rintega isn't the only cancer therapy that could move the needle for Celldex in the future.

The company is also conducting mid stage trials evaluating glembatumumab vedotin, or glemba, as part of a combination therapy in patients with an amenable genetic make-up and early stage trials of a CD-27 activating drug, varlilumab, that may have promise across a variety of cancers. A phase 2 study of glemba in triple negative breast cancer should complete enrollment next year and another study in metastatic melanoma is also under way. Meanwhile, varlilumab is being studied in phase 1/2 trials as an adjunct treatment for non-small lung cancer, metastatic melanoma, colorectal cancer, and kidney cancer.

Overall, Celldex has a slate of intriguing drugs that could succeed, but there are no guarantees, and that makes it risky. Having said that, Rintega's mid-stage results and the potential for a filing in brain cancer in 2017 suggest that this is a company risk-tolerant investors ought to consider buying in portfolios.