US-based biotechnology company Moleculin Biotech has reported positive initial efficacy data from the Phase II part of a Phase IB/II clinical trial of Annamycin to treat patients with soft tissue sarcoma (STS) lung metastases.

The trial's second phase analysed the intravenous infusion of Annamycin over two hours on the first day and subsequently after 20 days or one cycle equalling 21 days.

Data showed that 64% of the subjects who received Annamycin had stable disease through two cycles.

In addition, 36% and 14% of the subjects maintained stable disease through four cycles and six cycles respectively.

The trial is currently following up on three subjects for progression-free survival and 12 subjects for overall survival.

Moleculin chairman and CEO Walter Klemp said: “Our growing body of preliminary data demonstrated by Annamycin in the treatment of patients with STS lung mets continues to be encouraging and bolsters our confidence in its potential to be a meaningful option for patients. 

“While still preliminary, the rates of the median progression-free response and the trend being established for overall survival despite the patients in this study having received multiple prior chemotherapy regimens continues to exceed our expectations.”

The US Food and Drug Administration had previously granted fast track and orphan drug designation for Annamycin to treat soft tissue sarcoma.

Annamycin has also received orphan drug status for relapsed or refractory acute myeloid leukaemia (AML) indication. 

The next-generation anthracycline has demonstrated build-up in the lungs up to 30 times greater than the level of doxorubicin in animal models.

Last month, Moleculin Biotech dosed the first subjects in the Phase II part of a Phase Ib/II trial of Annamycin plus Cytarabine for AML treatment.

The company previously carried out two successful single-agent trials of Annamycin in the US and Europe.