Mayo Clinic researchers have found that an oral drug, apixaban, used to treat blood clots in patients undergoing cancer therapy, is safe and effective. The drug was associated with fewer major bleeding events and fewer recurrent blood clots, compared to low-molecular- weight heparin. 

Heparin injection is an anticoagulant. It is used to decrease the clotting ability of the blood and help prevent harmful clots from forming in blood vessels. This medicine is sometimes called a blood thinner, although it does not actually thin the blood. Heparin will not dissolve blood clots that have already formed, but it may prevent the clots from becoming larger and causing more serious problems.

Heparin is used to prevent or treat certain blood vessel, heart, and lung conditions. Heparin is also used to prevent blood clotting during open-heart surgery, bypass surgery, kidney dialysis, and blood transfusions.

It is used in low doses to prevent the formation of blood clots in certain patients, especially those who must have certain types of surgery or who must remain in bed for a long time. Heparin may also be used to diagnose and treat a serious blood condition called disseminated intravascular coagulation.

Their findings were presented at the annual meeting of the American Society of Hematology by Robert McBane II M.D., a Mayo Clinic cardiologist.

"Nearly 1 in 5 patients with cancer will develop a clot in the veins, referred to as either a deep vein thrombosis or pulmonary embolism," says Dr. McBane. "Clotting events can be deadly with pulmonary embolism being the second most common cause of death in cancer patients."

While twice-daily injections of low-molecular-weight heparin has been the traditional treatment of choice for cancer patients who suffer a venous clot, Dr. McBane notes that there are numerous limitations to this therapy.

"These injections can be painful and cause considerable bruising at the injection site. Injections are expensive at nearly $100 per day. And cancer patients may experience low platelet counts and be at risk for a clotting disorder called 'heparin-induced thrombocytopenia," said  Dr. McBane.

Dr. McBane noted that cancer and cancer treatment can be associated with kidney injury, which can limit the drug's use further. Finally, Dr. McBane says there isn't is a good antidote for this medication should a bleeding problem arise.

New blood thinners called 'direct oral anticoagulants'

"More recently, a number of new blood thinners called 'direct oral anticoagulants' have become available," says Dr. McBane. "As a class, these drugs have a number of advantages, including oral delivery, lack of interactions with foods or other medications, and the lack of a need for monitoring drug levels."

He says these qualities make this class of drug much easier to use than the traditional blood thinners. However, it was unclear whether these drugs could be used safely in cancer patients until now.

Dr. McBane says quality of life surveys, which were taken monthly throughout the six-month trial, showed that patients markedly preferred oral apixaban over injectable dalteparin. "We are hopeful that this medication will also improve medication compliance in cancer patients requiring blood thinner therapy."