Solbec mesothelioma trial shows promise

The news from a pre-clinical trial of Perth biopharma Solbec Pharmaceuticals' (ASX:SBP) lead anti-cancer compound SBO002 could hardly be more positive.

Medical researchers at the University of Western Australia have shown that not only does SBOP002 eradicate aggressive mesothelioma lung tumours in a rat model, it boosts immunity to the cancer, without the severe side-effects that accompany most chemotherapy drugs.

The company today described the first results from the SBP002 trial as "particularly promising".

Like many anti-cancer compounds, SBP2 is a plant extract, consisting of two glycoalkaloids extracted from the common roadside weed Solanum linneaeum, or devil's apple.

Unlike existing plant-derived cancer drugs like vincristine and vinblastine (Madagascar periwinkle) and taxol (Pacific yew), SBP002 has several modes of action that give it broad activity against many different cancers, as well as common inflammatory disorders.

It kills cancerous cells by inducing necrosis, and also suppresses production of the inflammatory cell-signalling molecule interleukin-6 (IL-6). IL-6 also makes patients in the terminal stages of cancer feel unwell, and induces severe wasting, known as cachexia.

After last-resort treatment with SBP002 under the Therapeutic Gods Administration's special access scheme, a number of patients in palliative care with metastatic melanoma and mesothelioma cancers have reported feeling well again, and gained weight as the drug reversed their cachexia.

The University of WA trial, supervised by Prof Bruce Robinson and Dr Richard Lake, has confirmed the empirical evidence that SBP002 positively modulates the immune response.

The researchers reported that the compound satisfied the three main criteria for immunological activity. It effectively destroys mesothelioma tumours in rats, and simultaneously increases the quantity of tumour antigens in lymph nodes draining the tumours, to boost the immune response.

Most importantly, according to the company, SBP002 does not kill lymphocytes, which coordinate an effective immune response against the cancer.

Mesothelioma, commonly caused by exposure to asbestos, is one of the most aggressive cancers, and is typically lethal within 12-18 months. No currently available therapy has extended patients' lives by more than a few months.

According to Solbec, up to 60,000 people in Australia will succumb to the disease by the time its incidence peaks in 2020, and mesothelioma rates are even higher in Europe and the US.

Mesothelioma is classified as a rare cancer, so Solbec is pursuing registration for SBP002 under the US Food and Drug Administration's 'orphan drug' scheme.

The UWA researchers have previously shown that SBP002, in contrast to standard cancer chemotherapeutics like Gemcitabine and Doxetaxol, actually suppresses productionof IL-6.

Solbec is investigating its potential as a therapy for the skin disease psoriasis, and plans to begin a Phase I clinical trial after mid-year. The company has lodged patents for its therapeutic use in a wide range of inflammatory disorders, including rheumatoid arthritis.