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FDA Puts Partial Hold on Clinical Trials of Cancer Drug Aldoxorubicin
CytRx Corporation has received notice from the FDA that its clinical trials of aldoxorubicin have been placed on partial clinical hold. All currently enrolled patients can continue receiving aldoxorubicin treatment or comparator drugs, as per the study protocols, but no new patients can be enrolled until the clinical hold is lifted.
The FDA indicated that the partial clinical hold was due to the reported death of a patient with advanced-stage cancer who did not qualify to participate in any of the ongoing aldoxorubicin clinical trials, but who had received aldoxorubicin under the company’s expanded access (“compassionate use”) program.
At the FDA’s request, CytRx will amend all aldoxorubicin study protocols to include appropriate inclusion/exclusion criteria, an additional patient screening assessment, and an evaluation of serum electrolytes before the administration of aldoxorubicin.
The company expects to announce preliminary results from an ongoing phase II trial of aldoxorubicin in patients with Kaposi’s sarcoma in the second quarter of 2015, and preliminary results from an ongoing phase II study of aldoxorubicin in patients with glioblastoma multiforme in the first half of 2015.
Doxorubicin, a widely used chemotherapeutic agent, is delivered systemically and is highly toxic, which limits its dose to a level below its maximum therapeutic benefit. Doxorubicin also is associated with numerous side effects, especially the potential for damage to heart muscle at cumulative doses greater than 450 mg/m2.
Aldoxorubicin combines doxorubicin with a single-molecule linker that binds directly and specifically to circulating albumin, the most plentiful protein in the bloodstream. Protein-hungry tumors concentrate albumin, thereby increasing the delivery of the linker molecule with the attached doxorubicin to tumor sites. Doxorubicin is released in the acidic environment of the tumor, but not in the neutral environment of healthy tissues. This allows greater doses (3.5 to 4 times) of doxorubicin to be administered while reducing its toxic effects. So far, there has been no evidence of clinically significant effects of aldoxorubicin on heart muscle, even at cumulative doses in excess of 2,000 mg/m2.
Source: CytRx Corporation; November 18, 2014.