New FDA Orphan Drugs: Sodium Phenylbutyrate, MGCD0103, Bendamustine HCl

Jill Taylor

September 07, 2007

September 7, 2007 — The US Food and Drug Administration (FDA) has granted orphan drug designation for sodium phenylbutyrate for the treatment of spinal muscular atrophy, MGCD0103 for the treatment of Hodgkin's lymphoma, and bendamustine HCl for the treatment of chronic lymphocytic leukemia.

Orphan Drug Sodium Phenylbutyrate for Spinal Muscular Atrophy

On March 20, the FDA granted orphan drug designation to sodium phenylbutyrate (Tikvah Therapeutics, Inc) for the treatment of spinal muscular atrophy (SMA), a debilitating disease caused by progressive degeneration of motor neurons in the spinal cord.

SMA is an inherited disorder, passed on to children by parents who carry the gene but who most often do not show symptoms of disease. The disease causes wasting of the voluntary muscles, producing weakness, and is the leading genetic killer of children under the age of 2 years. At present, there are no approved therapies for SMA.

Approximately 95% of individuals with SMA have genetic mutations that cause a survival motor neuron (SMN) protein deficiency that leads to motor neuron loss. Sodium phenylbutyrate is a histone deacetylase inhibitor that has been identified in in vitro systems and animal models as an agent that can increase the level of SMN protein. Data collected from in vitro studies and pilot clinical work suggests that phenylbutyrate treatment in SMA patients may improve motor function.

Orphan Drug MGCD0103 for Hodgkin's Lymphoma

On August 8, the FDA granted orphan drug designation to MGCD0103 (Pharmion Corporation and MethylGene, Inc) for the treatment of Hodgkin's lymphoma.

Hodgkin's lymphoma is marked by the presence of large abnormal cells known as Reed-Sternberg cells and causes painless enlargement of lymph nodes, spleen, or other immune tissue. Additional symptoms often include fever, night sweats, weight loss, and fatigue. Approximately 8190 new cases of Hodgkin's lymphoma are estimated to occur in the United States this year.

MGCD0103 is an orally administered histone deacetylase inhibitor that has been shown in a phase 2 clinical trial to produce an objective complete response plus partial response rate of 40% and a disease control rate (CR + Pr + stable disease for > 6 treatment cycles) of 45% in patients with relapsed or refractory disease.

Orphan Drug Bendamustine HCl ( Treanda) for Chronic Lymphocytic Leukemia

On August 17, the FDA granted orphan drug designation to bendamustine HCl ( Treanda, Cephalon, Inc) for the treatment of chronic lymphocytic leukemia (CLL).

CLL is the second most common type of leukemia in adults, with an estimated 15,000 new cases diagnosed annually in the United States. There may be few or no symptoms at early stages of the disease, and people with CLL may live for months or years without realizing it. Patients with CLL have an increased risk of developing certain infections and secondary malignancies.

Bendamustine is a purine analog/alkylator hybrid that has novel dual-action, antitumor effects. The compound has been shown to induce rapid, sustained, single- and double-strand DNA damage that results in apoptosis, or programmed cell death, in the tumor. In addition, the drug causes nonapoptotic cell death by inducing mitotic checkpoint inhibition.


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