Ron Winslow, Super-Survivors Fuel Cancer Hope. Wall Street Journal, Dec 5, 2014 (front page; under the heading “Early Promise”).
online.wsj.com/articles/cancers-super-survivors-how-immunotherapy-is-transforming-oncology-1417714379
Quote:
"Cancer immunotherapy comes in several forms. The drugs sparking the most interest are called checkpoint inhibitors. They work by releasing the natural brakes on the immune system, enabling its foot soldiers, called T cells, to attack tumors.
"It is hard to know how many patients whose cancers have metastasized, or spread, have enjoyed sustained survival following immunotherapy treatment. An analysis of 4,846 advanced melanoma patients treated with one checkpoint inhibitor— Bristol-Myers Squibb Co’s Yervoy—found that 21% were still alive three years later. * * * Especially striking is how good the long-term prospects were for people who survived at least three years.
"James Allison [PhD], head of immunology at MD Anderson Cancer Center in Houston, whose seminal discovery about the immune system and cancer in the mid-1990s [at University of California Berkeley] laid the groundwork for many of the current advances.
"Newer drugs that work similarly to Yervoy, but on different immune-system brakes, are getting even better early results and are extending the benefits beyond melanoma to other cancers.
In cancer immunotherapy, "most patients don’t respond the way the super-survivors have [eg, 79% of those who takes Yervoy (quotation 2)]
"While side effects of the new drugs [in cancer immunotherapy] are relatively mild for some patients, others have developed potentially devastating complications caused by an out-of-control immune system [supposedly due to the releasing of the natural brakes on the immune system (quotation 1); supposedly, because molecular mechanisms have not been worked out--nobody really knows for sure what is going on; the concept of a brake in immune system is unproven]. Some patients have died as a result.
"Bert Vogelstein [MD], director of the Ludwig Center at Johns Hopkins Kimmel Cancer Center in Baltimore[:] 'But the reality is that most are not [responding to checkpoint inhibitors].'
"Yervoy costs more than $120,000 for a four-course treatment, while Merck & Co’s Keytruda, approved in September for advanced melanoma, costs $12,500 a month, or $150,000 for a year.
"Bristol-Myers’s drug Yervoy, which is based on Dr Allison’s discoveries, blocks an immune system brake called CTLA-4. Merck’s Keytruda inhibits a brake called PD-1.
"Another approach involves genetically modifying certain T cells outside the body, creating what are called CAR T cells [where CAR stands for 'chimeric antigen receptor'], and infusing them back to attack targets on the surface of cancer cells. Novartis AG , closely held Juno Therapeutics Inc, Kite Pharma Inc., and a collaboration between Bluebird bio and Celgene are pursuing this strategy.
"most current cancer treatments, including chemotherapy, radiation * * * take direct aim at the tumor * * * With immunotherapy, 'We’re treating the immune system, not the cancer,' says Dr Allison.
"For years, scientists thought the immune system didn’t recognize tumors at all. Then research on biopsy specimens revealed that T cells often succeed in infiltrating the environment around tumors, but either fail to mount an adequate response or hold the cancer at bay for years before finally being overmatched.
"The challenge was to widen the benefit to more patients and more cancers. For reasons of biology, melanoma is more vulnerable than most other tumor types to attacks by the immune system. For immunotherapy to become a mainstay of cancer treatment, it needs to prove effective against more tumors. |