CytRx soars on positive results for PhIIb sarcoma drug study

CytRx CEO Steven Kriegsman

After months of building investors' expectations for its Phase IIb study for the cancer conjugate aldoxorubicin as a potential first-line treatment for soft tissue sarcoma, the small-cap biotech CytRx ($CYTR) today said that it found an 80% to 100% improvement in the progression-free survival rate for its new-and-improved chemotherapy drug compared to the original chemo, sending its shares up more than 70% in premarket trading.

Looking at the "blinded central lab review," the biotech says that the PFS rate for their drug conjugate hit 5.7 months, compared to 2.8 months for doxorubicin alone. An intent-to-treat analysis, the company added, found a PFS rate of 8.4 months for the aldoxorubicin arm and 4.7 months in the chemo-only group. The overall response rate was 25.4% for aldoxorubicin and 5.4% for the chemo arm.

"Aldoxorubicin is a major advance for treating soft tissue sarcomas," crowed CytRx CEO Steven Kriegsman in a statement. "We extend gratitude to the investigators who so adeptly managed the conduct of this trial and to the patients and their families who participated in it. These data prove that by applying our proprietary linker technology to target the release of doxorubicin directly at the site of cancer we are able to safely increase the dosage of doxorubicin by approximately three and one-half to four times with tremendous clinical benefit to the patient."

Aldoxorubicin is billed as a major improvement over doxorubicin. The drug is designed to bind to albumin using an acid sensitive linker. Albumin concentrates in tumors, where the acidic environment degrades the linker and releases the chemo directly into the tumor. In clinical trials investigators have been multiplying the dose of doxorubicin, reviewing data that supports their claim that the conjugate generally steers clear of healthy tissue.

The results of this study have been crucial to tiny CytRx, which had a market cap of $100 million before today's data release, especially since its other program in the clinic blew up earlier this year. The Los Angeles-based biotech managed to skirt any serious damage to its stock price last May when it scuttled tamibarotene after that drug floundered in a Phase IIb trial for non-small cell lung cancer, largely by keeping investors focused on its lead drug. CytRx execs have been promising a fresh round of data for their Phase IIb trial, one of 5 clinical-stage programs for the drug.

- here's the release