Chicago: A drug made by Japan’s Eisai Company that was originally derived from sea sponges helped extend lives of patients with soft-tissue cancers known as sarcomas by two months, a significant advance for these rare cancers with few treatment options, Belgian researchers said on Saturday.

The researchers studied the drug, known as eribulin, in 452 patients with two forms of sarcomas — leiomyosarcoma, which starts in smooth muscles, and adipocytic sarcoma, which starts in fat tissue.

‘For a disease where such few treatment options exist, a two month improvement in survival is significant,’ said Dr Patrick Schoffski, a medical oncologist at University Hospitals Leuven in Belgium, who presented the findings at the American Society of Clinical Oncology meeting on Saturday.

Patients were treated with either eribulin or the chemotherapy drug dacarbazine until their disease progressed. All patients had cancers that had advanced despite treatment with two or more prior therapies.

In the study, patients treated with eribulin lived an average of 13.5 months, compared with 11.5 months in those treated with dacarbazine.

Patients in both study groups experienced side effects, but patients in the eribulin group were more likely to experience severe and potentially life-threatening side effects.

Dr Gary Schwartz, an ASCO spokesman and chief of the Haematology and Oncology Division at Columbia University, said the results were encouraging in a disease that is ‘notoriously difficult to treat’, but the results must be weighed against the risk of side effects.

The study was funded by Eisai, which sells eribulin for women with metastatic breast cancer under the brand name Halaven.