CytRx unveils initial results of phase 3 trial of aldoxorubicin in patients with second-line STS

In accordance with the FDA-granted special protocol assessment, the current analysis occurred following 191 progression events.

Because enrollment was interrupted by a partial clinical hold in November 2014, this analysis did not provide for sufficient follow-up for the nearly two-thirds of patients who entered the Phase 3 study after the hold was resolved and enrollment resumed.  This resulted in nearly half of all patients being censored (excluded) from the current progression free survival (PFS) evaluation.  CytRx expects to conduct a second analysis, which will include longer patient follow-up and allow for greater maturation of all endpoints.

The Company expects to announce the results of this evaluation and hold an end-of-Phase 3 meeting with the Food and Drug Administration (FDA) in the fourth quarter of 2016.

The partial clinical hold was related to a single patient enrolled in a compassionate use study, which was subsequently resolved successfully.

For the current evaluation, the study did not show a significant difference between aldoxorubicin and investigator's choice therapy for PFS, with a median of 4.17 months and 4.04 months, respectively, for the study's primary endpoint (hazard ratio: 0.91).  However, the most immediate indications of therapeutic activity, objective response rate (ORR) and disease control rate (ORR + stable disease ≥ 4 months), showed a near doubling in the aldoxorubicin arm compared to investigator's choice, including in patients who previously received treatment with doxorubicin.

Disease control rate for aldoxorubicin was significantly greater than investigator's choice therapy in the intent-to-treat population (p=0.048) as well as in patients who received prior doxorubicin (p=0.0415). Patients continue to be followed for overall survival (OS), a secondary endpoint of the trial.

"While results from this current analysis are immature, a near doubling of response rates with aldoxorubicin suggests a highly active therapy which may benefit certain patients with soft tissue sarcoma," said Sant Chawla, M.D., F.R.A.C.P., Principal Investigator and the Director of the Sarcoma Oncology Center in Santa Monica, California.

"Because enrollment was interrupted by a clinical hold, both PFS and response data need to be analyzed at a future date to account for patients enrolled later in the trial.  I look forward to this subsequent analysis providing a more complete understanding of aldoxorubicin's potential in this very challenging disease."

Treatment-related adverse events for aldoxorubicin were consistent with those observed in prior studies.  Aldoxorubicin was not associated with clinically significant cardiac, kidney or liver toxicities.  The Company plans to present updated results of the study at an upcoming medical meeting.

"The complexity, in terms of tumor diversity and primary location, makes soft tissue sarcoma extremely difficult to treat, especially in the relapsed and refractory setting, resulting in few treatment advances over the last four decades," said Daniel Levitt, M.D., Ph.D., Executive Vice President and Chief Medical Officer of CytRx.

"This first-of-its-kind study in STS included a comparator arm with multiple regimens, allowing for treatments to be matched to specific sarcoma subtypes.  Despite a requirement for this challenging study design, aldoxorubicin demonstrated markedly greater activity over investigator's choice therapy.  That said, the unforeseen clinical hold that interrupted this study impacted the outcome of the current evaluation, underscoring a need for a subsequent analysis."

"In over 550 patients treated to date, aldoxorubicin has demonstrated anti-tumor activity in multiple tumor types and has shown a manageable safety profile," said Steven A. Kriegsman, CytRx's Chairman and CEO.

"With approximately $68.2 million in cash and equivalents as of our last 10-Q filing, CytRx is funded through the next Phase 3 STS trial analysis and through a readout of our global Phase 2b trial of aldoxorubicin in small cell lung cancer.  We are deeply grateful for the continued support and commitment of the patients, their families, the investigators and clinical support professionals participating in the Phase 3 trial."