Vorinostat Reduces Formation of Brain Metastases in Mice

The drug vorinostat is able to cross the blood-brain barrier and reduce the development of large metastatic tumors in mice brains by 62 percent when compared to mice that did not receive the drug, according to a new study. In humans, the drug has been approved by the U.S. Food and Drug Administration for the treatment of a cancer called cutaneous T-cell lymphoma but can be used experimentally to study its effectiveness against other cancers. This research, by investigators at the National Cancer Institute (NCI) and their collaborators, appears online in Clinical Cancer Research.

For people, while various therapies are improving the survival of breast cancer patients, the incidence of breast cancer spreading to the brain is increasing. Brain metastases of breast cancer have proven to be largely untreatable because the blood-brain barrier, which arises from the specialized structure of blood capillaries in the brain, severely limits drug access and many drugs are actively transported out of brain at this barrier. Consequently, the one-year survival estimate for breast cancer patients after a diagnosis of brain metastasis is only about 20 percent.

Vorinostat has been found to slow the growth of primary tumors of several different types of cancer in mice. Previous studies have suggested that the drug can be taken up by the brain, although little was known about its effects on metastatic tumors. Therefore, to study the effect of vorinostat on the formation of brain metastases, scientists used a mouse model of human breast cancer. Human breast cells were cultured in the laboratory and were injected into mice with compromised immune systems. The breast cancer cells then migrated to the brain, forming metastases. "Drugs that can cross the blood-brain barrier and reduce the size and incidence of metastatic tumors are urgently needed," said Patricia S. Steeg, Ph.D., study author, Center for Cancer Research, NCI. The researchers found that vorinostat was absorbed readily into normal mouse brains, and accumulation of the drug was up to three-fold higher in some metastases treated with this drug when compared to surrounding brain tissue. Vorinostat also reduced the development of tiny tumors (micrometastases) in mice by 28 percent when compared with mice that did not receive this therapy.

www.nci.nih.gov

Drugs Approved by FDA in 2009 for Cardiology and Vascular Disease

Drugs approved by the Food and Drug Administration (FDA) for sale in the United States:

Adcirca (tadalafil); Eli Lilly; For the treatment of pulmonary arterial hypertension. Approved May 2009. Adcirca (tadalafil) is an oral inhibitor of phosphodiesterase type 5 (PDE5), the enzyme responsible for the degradation of cyclic guanosine monophosphate (cGMP). Adcirca is supplied as a 20 mg tablet for oral administration. The recommended initial dose of the drug is 40 mg (two 20 mg tablets) taken once daily with or without food.

Adverse events associated with the use of Adcirca may include headache, dyspepsia, myalgia, nausea, back pain, nasopharyngitis, flushing, respiratory tract infection, pain in extremity.

Atryn (antithrombin recombinant lyophilized powder for reconstitution); GTC BioTherapeutics; For the prevention of peri-operative and peri-partum thromboembolic events. Approved January 2009. Atryn is a recombinant antithrombin. Recombinant antithrombin is produced by recombinant DNA technology using genetically engineered goats. The amino acid sequence of recombinant antithrombin is identical to that of human plasma-derived antithrombin. Antithrombin plays a central role in the regulation of hemostasis and is the principal inhibitor of thrombin and Factor Xa5, the serine proteases that play pivotal roles in blood coagulation. Antithrombin neutralizes the activity of thrombin and Factor Xa by forming a complex which is rapidly removed from the circulation.

Adverse events associated with the use of Atryn may include intra-abdominal hemorrhage, application site pruritus, feeling hot, non-cardiac chest pain, hepatic enzyme abnormal, hemarthrosis hematuria, hematoma.

Eficient (prasugrel); Eli Lilly; for the prevention of thrombotic cardiovascular complications in acute coronary syndromes. Approved July 2009. Efient (prasugrel) works by reducing the tendency of platelets, the blood particles responsible for clotting, from sticking or clumping together. Prasugrel blocks a specific receptor on the platelet surface, P2Y12 adenosine diphosphate (ADP), and prevents platelets from clumping, which can result in clogged arteries and may lead to heart attack.

Adverse events associated with the use of Efient may include TIMI major or minor bleeding, hypertension, hypercholesterolemia/hyperlipidemia, headache, back pain, dyspnea, nausea, dizziness.

Livalo (pitavastatin); Kowa Company; For the treatment of primary hyperlipidemia and mixed dyslipidemia. Approved August 2009. Livalo is a HMG-CoA reductase inhibitor. Livalo is specifically indicated as an adjunctive therapy to diet to reduce elevated total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), apolipoprotein B (Apo B), triglycerides (TG), and to increase HDL-C in adult patients with primary hyperlipidemia or mixed dyslipidemia. Livalo is supplied as a tablet (1, 2 and 4 mg) for oral administration. The recommended initial dose of the drug is 2 mg and the maximum dose is 4 mg. After initiation or upon titration of Livalo, lipid levels should be analyzed after 4 weeks and the dosage adjusted accordingly.

Adverse events associated with the use of Livalo may include back pain, constipation, diarrhea, myalgia, pain in extremity.

Multaq (dronedarone); Sanofi-aventis; For the treatment of paroxysmal or persistent atrial fibrillation or atrial flutter. Approved July 2009. Multaq (dronedarone) is a benzofuran derivative with antiarrhythmic properties belonging to all four Vaughan-Williams classes. Multaq is specifically indicated to reduce the risk of cardiovascular hospitalization in patients with paroxysmal or persistent atrial fibrillation (AF) or atrial flutter (AFL), with a recent episode of AF/AFL and associated cardiovascular risk factors who are in sinus rhythm or who will be cardioverted. Multaq is supplied as a 400mg tablet designed for oral administration. The recommended initial dose of the drug is 400 mg twice daily, once in the morning with a meal and once in the evening with a meal.

Adverse events associated with the use of Multaq may include diarrhea, asthenic conditions, nausea, skin infections, abdominal pain, bradycardia.

Tyvaso (treprostinil); United Therapeutics; For the treatment of pulmonary arterial hypertension. Approved July 2009. Tyvaso is a prostacyclin analogue. It directs vasodilation of pulmonary and systemic arterial vascular beds and inhibits platelet aggregation. Tyvaso is specifically indicated to increase walk distance in patients with WHO Group I pulmonary arterial hypertension and NYHA Class III symptoms. Tyvaso is suppled as a solution designed for oral inhalation. Tyvaso should be dosed in 4 separate, equally spaced treatment sessions per day, during waking hours. The treatment sessions should be approximately 4 hours apart.

Adverse events associated with the use of Tyvaso may include cough, headache, throat irritation, nausea, flushing, syncope.

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