Source: Celldex Therapeutics

What: After reporting solid efficacy in mid stage trials for its brain cancer drug, Rintega, on November 20, shares in Celldex Therapeutics (NASDAQ:CLDX) climbed by another 12% today.

So what: Today's move will be tacked onto an impressive 53.6% return that shareholders have enjoyed since the end of September.

CLDX data by YCharts

Shares climbed on renewed excitement for Rintega, an immunotherapy for glioblastoma, a rare form of brain cancer.

Typically, patients with glioblastoma and a specific variant of the EGFR protein known as EGFRvIII have a poor prognosis; however, long-term follow up data from Rintega's phase 2 trials shows that 25% of Rintega patients are alive two years after Rintega therapy.

Since none of the patients in the control arm of the study remain alive, the finding suggests that Rintega could potentially change the standard of care for patients with this tough-to-treat cancer.

In addition to the overall survival data, Celldex also reports that patients in the Rintega arm of this study continue to show clinical benefit in progression free survival, overall response rate, and reduced levels of use of steroids.

The findings relating to steroid use are particularly intriguing because steroid use can lead to side effects that reduce patient quality of life. While no one in the control arm of the study was able to discontinue steroid use during the follow up period, one third of patients who were taking steroids at the onset of the phase 2 trial were able to stop taking steroids for six months or longer after taking Rintega.

Now what: The study evaluated Rintega alongside Avastin in recurrent glioblastoma, but another ongoing phase 3 trial is testing out the two drug combination in newly diagnosed glioblastoma patients.

Independent monitors will take a look at the phase 3 data from this trial at the 75% interim mark early next year and if those monitors find similar efficacy, then that trial could be stopped early.

Overall, about 30% of glioblastoma patients have the amenable EGFRvIII variant that Rintega targets, so a clinical success could make Rintega one of the most important advances in brain cancer treatment in years.

Although that prospect is exciting, cancer is notoriously tough to treat and up to 40% of late stage trials fail. Therefore, investors should remember that Celldex Therapeutics still has some hurdles to overcome before Rintega reaches the finish line. 

 

Todd Campbell owns shares of Celldex Therapeutics. Todd owns E.B. Capital Markets, LLC. E.B. Capital's clients may have positions in the companies mentioned. The Motley Fool recommends Celldex Therapeutics. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.