Merrimack Pharmaceuticals, Inc. (MACK) , a maker of oncology drugs, rose the most in more that a year after reporting strong results from its latest treatment for pancreatic cancer.

Shares jumped 53.53 percent to $6.74 per share in afternoon trading Thursday as Wall Street weighs the new cancer therapy which has the potential to become the next most-expensive drug.

Merrimack reported earlier today that patients who took a drug called MM-398 lived 6.1 months, compared with 4.2 month if receiving only traditional chemo regimens.

"Given that there have only been a handful of successful Phase III trials in pancreatic cancer in the past 25 years, it is gratifying to have the first positive Phase III trial in the post-gemcitabine setting," CEO Robert Mulroy said in a statement.

Pancreatic cancer patients has a extremely low survival rate, with less than 23 percent still living one year after diagnosis. Few options are available for treating the tumor that is difficult to detect in early stages. Apple’s (AAPL) former CEO Steve Jobs and “tough-guy” actor Patrick Swayne were among more than 40,000 people succumbing to the lethal tumor.

For years, doctors and investors were disappointed by the lack of major breakthroughs in pancreatic cancer research, pressuring the Pancreatic Cancer Action Network to take a more concrete goal of doubling the survival rate by 2020. As major drug maker narrowed down their research focus, promises emerged from several companies earlier this year.

Celgene’s ($CELG) Abraxane extended the lives of patients by almost two months to an average of 8.7 months, said the company in a statement.  The regimen cost $8,000 dollars a month, which is more expensive than chemotherapy and sets up a stage for similar drugs under development.

Pending approval from the Food and Drug Administration, Merrimack will debut the drug later this year, expecting it to be a new blockbuster. But analysts pointed to the fact that MM-398 only has marginal improvements over competitors and could not hold up to its advantages for long. Merrimack filed for IPO in 2012 to raise capital for its pancreatic cancer drug development.