CytRx begins Phase III study of aldoxorubicin to treat soft tissue sarcoma

26th March 2014 (Last Updated March 26th, 2014 01:00)

US-based biopharmaceutical research and development firm CytRx has started a global Phase III clinical trial to assess the efficacy and safety of aldoxorubicin as a second-line treatment for patients with soft tissue sarcoma (STS).

Soft-tissue sarcoma

US-based biopharmaceutical research and development firm CytRx has started a global Phase III clinical trial to assess the efficacy and safety of aldoxorubicin as a second-line treatment for patients with soft tissue sarcoma (STS).

The multi-centre, randomised, open-label Phase III trial will be carried out under a special protocol assessment with the US Food and Drug Administration (FDA).

The company said that aldoxorubicin combines the chemotherapeutic agent doxorubicin with a new linker-molecule that binds specifically to albumin in the blood to allow for delivery of higher amounts of doxorubicin without several of the major treatment-limiting toxicities seen with administration of doxorubicin alone.

Around 400 patients with metastatic, locally advanced or unresectable soft tissue sarcomas who have either not responded to, or have progressed following treatment with, one or more systemic regimens of non-adjuvant chemotherapies will be enrolled in the trial.

In the trial, patients will be randomised 1:1 to be treated with aldoxorubicin or the investigator's choice of an approved chemotherapeutic regimen, including doxorubicin, ifosfamide dacarbazine, pazopanib (Votrient), or gemcitabine plus docetaxel, with up to three comparator regimens to be selected by the investigator at each clinical site.

Primary endpoint of the trial is progression-free survival (PFS), while secondary endpoints include overall survival, response rates and safety.

"Aldoxorubicin has demonstrated highly statistically significant improvements over doxorubicin for STS in multiple outcomes, including PFS, which is extraordinary for a single agent treating these types of tumours."

In January 2014, CytRx received approval from the FDA to amend the Phase III protocol to continue dosing patients with aldoxorubicin until disease progression, which creates the potential for substantially improved Phase III efficacy results.

Patient enrolment in the Phase III clinical trial is expected to be complete in 2015.

The company said that in a Phase Ib/II trial, partial responses were observed in five of 13 patients with metastatic soft tissue sarcomas who had progressed following initial chemotherapy.

In the Phase Ib/II trial, eight of 13 patients showed evidence of tumour shrinkage; five of the eight patients had received prior doxorubicin chemotherapy and had not showed tumour reduction.

Sarcoma Oncology Center director and principal investigator of the Phase III pivotal trial Sant Chawla said that the centre has seen few advances in the treatment of soft tissue sarcomas, and only one US regulatory approval, in over two decades.

"Aldoxorubicin has demonstrated highly statistically significant improvements over doxorubicin for STS in multiple outcomes, including PFS, which is extraordinary for a single agent treating these types of tumours," Chawla said.

"Given aldoxorubicin's side-effect profile, I believe that it could one day become the treatment of choice for STS, and its potential extends to a wide range of other cancers where anthracyclines are indicated as first- or second-line treatment, including breast, ovarian, multiple myeloma and acute myelocytic leukemia."

The trial will be carried out at around 100 clinical sites in the US, Europe, Canada, Latin America, Asia Pacific and Australia.


Image: Undifferentiated soft tissue sarcoma in left lung of young child. Photo: courtesy of ThatPeskyCommoner.