CytRx Corporation, a biopharmaceutical company specializing in oncology, announced that it is initiating a multi-centre phase 2b clinical trial with its oncology drug candidate tamibarotene in combination with chemotherapeutical agents for the treatment of patients with advanced Non-Small-Cell Lung Cancer (NSCLC).

“Intensive chemotherapy treatment for patients with late-stage NSCLC appears to provide some benefit; however, the median survival is still about one year, with progression-free survival of around six months,” said CytRx chief medical officer Daniel Levitt, MD, PhD “A recent phase 2 clinical trial demonstrated statistically significant results when adding All Trans Retinoic Acid, or ATRA to a regimen of paclitaxel and cisplatin as initial treatment for patients with advanced NSCLC. Tamibarotene is a synthetic retinoid that is 10- to 20-fold more potent than ATRA; thus we believe that it has great promise to be a new weapon against this devastating cancer.”

The phase 2 clinical trial conducted by Arrieta et al. and published in the peer-reviewed Journal of Clinical Oncology (2010; 28: 3463-3471)compared ATRA added to a regimen of paclitaxel plus cisplatin to a regimen of paclitaxel plus cisplatin alone as a treatment for patients with advanced NSCLC.

The group administered ATRA plus the chemotherapy agents showed improved response rates of 55.8% versus 25.4%, and increased progression-free survival of 8.9 months versus 6.0 months. Median overall survival was increased from 9.5 months to 23.5 months when ATRA was added to the above chemotherapy regimen, representing a 14-month median extension of life.

In CytRx's randomized Phase 2b clinical trial, patients with stage IIIB or IV NSCLC will be treated with up to six cycles of paclitaxel plus carboplatin and either tamibarotene or placebo. The primary objective of the clinical trial is to determine the objective response rate (complete and partial responses) and progression-free survival. Secondarily, the study will evaluate overall survival, quality-of-life and the pharmacokinetics of tamibarotene in this population. The clinical trial, which is expected to enroll approximately 140 patients, will be conducted in several clinical sites in the US and Mexico.

CytRx pPresident and CEO Steven A. Kriegsman said, “Tamibarotene has shown highly encouraging results in patients with advanced acute promyelocytic leukaemia or APL, with several reports of total elimination of the disease in patients who failed multiple other treatments. Due to its increased potency compared with ATRA and its ability to potentially avoid some of the toxic side effects of ATRA, tamibarotene could be a substantial improvement over ATRA for treating multiple cancers. In the event that tamibarotene shows a substantial extension of life for sufferers of non-small-cell lung cancer, it would present a multi-billion dollar market opportunity for CytRx.”

More than 220,000 new cases of lung cancer will occur in the US this year and more than 1.5 million worldwide. Deaths due to lung cancer account for the majority of cancer-related deaths (180,000 in the US, 1.35 million worldwide) and the five-year survival ranges between 8-15%. NSCLC accounts for 85-90% of all lung cancers, with subsets adenocarcinoma representing 35-40%, squamous cell carcinoma accounting for 25-30% and large cell carcinoma accounting for 10-15% of lung cancers.

Tamibarotene is an orally available, rationally designed, synthetic retinoid compound. CytRx holds the North American and European rights to certain tamibarotene intellectual property for the treatment of APL and retains an option to expand its licenses for the use of tamibarotene in other fields in oncology, including multiple myeloma, myelodysplastic syndrome and certain solid tumours in the US, and multiple myeloma, myelodysplastic syndromes and solid tumours other than hepatocellular carcinoma in Europe.

The efficacy and safety of tamibarotene as a third-line treatment for APL is currently being evaluated in the Phase 2 Star-1 registration trial, which is being conducted under a Special Protocol Assessment (SPA). In June 2009 CytRx reported that, of the 11 patients enrolled in the Star-1 trial at that time, three (27%) achieved a hematologic complete response and four (36%) a morphologic leukaemia-free state. In December 2009, favourable preliminary results from the Star-1 registration trial were presented at the Annual Meeting of the American Society of Haematology (ASH).

The FDA has granted Orphan Drug Designation for APL and Fast Track Designation for the use of tamibarotene in patients with relapsed or refractory APL following treatment with ATRA and ATO. In addition, tamibarotene has been granted orphan medicinal product status by the European Medicines Agency for the treatment of APL. The efficacy of tamibarotene was demonstrated in two Phase 2 studies conducted in Japan in a total of 63 Japanese subjects with APL.

The overall complete response rate in these subjects was 60%. In subjects experiencing their first relapse, the overall complete response rate was 81%. A dose escalation study with tamibarotene combined with ATO in patients with relapsed APL is currently being conducted by North-western University under the leadership of Dr. Jessica Altman, Assistant Professor of Medicine, at the North-western University Feinberg School of Medicine.

CytRx Corporation is a biopharmaceutical research and development oncology company engaged in the development of high-value human therapeutics. The CytRx oncology pipeline includes three programs in clinical development for cancer indications: bafetinib, tamibarotene and INNO-206.