The rate of pancreatic cancer, one of the deadliest types of cancer, has risen steadily over the past decade -- the American Cancer Society estimates that more than 45,000 new cases in the U.S. were reported in 2013 alone.

Patients with pancreatic cancer have an overall five-year survival rate of 6%, compared to the 22% and 16% respective five-year survival rates for breast and lung cancers. There are two main reasons for that bleak percentage -- pancreatic cancer rarely produces symptoms until it has metastasized, and there is a glaring lack of available treatments.

Let's take a closer look at the pancreatic cancer treatments of the past, and discuss three key drugs -- from Roche (RHHBY -1.15%), Astellas, Celgene (CELG), Incyte (INCY -0.39%), and Novartis (NVS -1.28%) -- that health-care investors should be aware of.

A look at past treatments
Eli Lilly's (LLY -0.54%) chemotherapy drug Gemzar (gemcitabine) is widely considered the standard of care for pancreatic cancer. Generic gemcitabine is available from numerous companies.

In the past, companies have combined various targeted treatments with gemcitabine in an attempt to increase their survival benefit.

These efforts include Bristol-Myers Squibb/Eli Lilly's Erbitux, Roche's Avastin, Pfizer's Inlyta, and Amgen/Bayer's Nexavar, among others. Unfortunately, none of these drugs has shown a significant survival benefit when combined with gemcitabine.

Meanwhile, Folfirinox, a potent combination of four different chemotherapy drugs, achieved an 11.1 month median survival rate when administered as a first-line therapy. Those results, first presented at ASCO 2010, showed that 48% of patients on Folfirinox survived for more than a year, compared to 20% in the gemcitabine arm. However, Folfirinox has major toxicity issues due to its potency.

Roche and Astellas' Tarceva
Tarceva, from Roche and Astellas, is one of the only targeted treatments for pancreatic cancer that has shown an additional survival benefit when combined with gemcitabine. The drug is marketed in the United States by Roche and Astellas and overseas by Roche.

Tarceva, which is also approved for non-small cell lung cancer (NSCLC), was approved by the FDA in 2005 as a treatment for late-stage pancreatic cancer patients with metastasized and inoperable tumors. Patients given a combination of Tarceva and gemcitabine showed a 23.8% one-year survival rate, compared to 19.4% in the placebo plus gemcitabine arm.

Tarceva showed a median survival rate of 6.7 months versus 4.7 months for the placebo, which still fell short of Folfirinox's 11.1 months. While Tarceva's added benefits to gemcitabine are encouraging, it is hardly a game-changing treatment.

Nonetheless, Tarceva remains a top treatment for lung and pancreatic cancers, generating $766 million in revenue for Roche in the first half of 2013 and accounting for 4% of the company's top line.

Celgene's Abraxane
Meanwhile, Celgene's Abraxane, a newer targeted treatment administered with gemcitabine, was approved by the FDA in September 2013 and in the EU earlier this month. The drug is also approved for advanced NSCLC and breast cancer.

Abraxane is considered to be a possible replacement for Tarceva, since it demonstrated a median survival rate of 8.5 months when combined with gemcitabine, compared to 6.7 months in the gemcitabine-only arm during phase 3 trials. While that figure is more impressive than Tarceva's, it still doesn't match Folfirinox's survival rate, which Celgene originally thought it could top with a median survival rate of 12.2 months during phase 2 trials. Nonetheless, Abraxane remains a less toxic option than Folfirinox.

Last quarter, sales of Abraxane rose 59.5% year over year to $169.6 million, and the additional approvals for pancreatic cancer could boost sales significantly in 2014. Analysts are optimistic about Abraxane's growth prospects, forecasting peak annual sales of $2.1 billion.

Abraxane is also considered to be Celgene's best hope at diversifying its portfolio beyond the blood cancer drug Revlimid, which accounts for 65% of its top line.

Incyte and Novartis' Jakafi
Last but not least, Jakafi, a blood cancer drug marketed by Incyte in the United States and overseas by Novartis, has shown promise as a treatment for pancreatic cancer. Jakafi, which is currently only approved for the blood disorder myelofibrosis, blocks certain enzymes which affect blood cell production.

Shares of Incyte surged in August 2013, after the company reported interim data from its phase 2 study of the drug in pancreatic cancer. The drug is being tested with capecitabine, an oral chemotherapy drug, instead of gemcitabine. Investigators stated that patients given Jakafi and capecitabine exhibited a 42% six-month survival rate, compared to 11% in its placebo plus capecitabine arm.

Incyte did not disclose further details regarding the study's subgroup -- which means that investors shouldn't believe that Jakafi is poised to become the next Abraxane just yet. However, Incyte is expected to present the full phase 2 results at ASCO 2014, which could be a major positive catalyst for the stock this year.

Last quarter, Incyte only reported $60.2 million in Jakafi sales, but the drug is forecast to eventually grow into a blockbuster drug with over $1 billion in peak annual sales.

The Foolish takeaway
Pancreatic cancer remains a tough target for companies to treat. However, newer treatments like Abraxane and higher potency drugs like Folfirinox are helping late-stage patients extend their lives longer than ever. Other next-generation treatments, such as antibody-drug conjugates or immunotherapy, might also yield better results than chemotherapy alone.

New potential treatments are also emerging -- scientists at the Cancer Research UK Cambridge Institute recently reported that AMD3100 (Sanofi's Mozobil), could wipe out pancreatic cancer in just six days by breaking through the thick protective walls that surround pancreatic cancer cells. Although researchers have only tested AMD3100 on mice, human trials are expected to start later this year.

In closing, the best play on pancreatic cancer treatments is Celgene, since Abraxane was only recently approved and exhibits high growth potential to complement its current portfolio of blood cancer drugs. Investors should also keep an eye on speculative treatments such as Jakafi and Mozobil, which could potentially turn the market for pancreatic cancer treatments upside down.