Medical cannabis promising for hard-to-treat breast cancers

Biotech company Zelda Therapeutics (ASX:ZLD) has announced positive results from its ongoing preclinical research into the use of cannabinoids as anticancer agents. The results were generated by cannabis cancer researchers at Complutense University of Madrid, led by Professor Cristina Sánchez and Professor Manuel Guzmán.

Therapeutics is bringing together leaders in the field to develop a natural cannabis-based therapy which has the potential to provide patients with more comfort and increase survival rates. The company’s focus is to generate data packs in a form typically expected by the biopharma industry, with the ultimate aim to license this intellectual property to a major group better resourced to progress into formal human clinical trials.

Building on its initial proof-of-concept results announced in November 2016, the latest experiments expanded the number of cancer cell lines being tested to include:

• Hormone-receptor positive (ER+/PR+) — typically treated with surgery and chemotherapy agents such as tamoxifen, although resistance can build to standard drugs;
• HER2+ — typically treated with antibody drugs such as Herceptin, with relatively high success rates; and
• Triple negative — an aggressive form of breast cancer with limited treatment options.

The experiments tested THC-rich and CBD-rich cannabis extracts supplied by Zelda’s partner, Aunt Zelda’s. The in vitro study was carried out in at least two different cell lines of each of the three cancer subtypes.

The study demonstrated that a statistically significant anticancer effect was produced across multiple cell lines and all three cancer subtypes. In particular, the THC-rich formulation showed significantly greater anticancer effect than pure synthetic THC, suggesting that full extracts have greater efficacy than pure compounds. This effect was consistent across all cancer subtypes, suggesting a novel mechanism of action that could form the basis for the development of future therapies.

“We … believe there is growing evidence to consider cannabinoids as part of the future treatment regimes for breast cancer, particularly for triple negative tumours that currently have limited treatment options,” Zelda Therapeutics Executive Chairman Harry Karelis said. There is a long way to go before this approach reaches formal human clinical trials but importantly, this data supports the anecdotal experiences already seen in patients in California.”

The results provide support to continue the study of Zelda formulations as anticancer therapeutics in their own right or in combination with current chemotherapy and radiotherapy regimes. A series of follow-on in vitro studies are expanding the study of CBD-rich extracts alone and in combination with THC-rich extracts to determine if there is a synergistic effect.

In addition, an expanded in vivo/animal study is examining the anticancer effect of Zelda’s extracts compared to pure THC and pure CBD, as well as certain chemotherapy agents against HER2+ and triple negative human tumours hosted in rodents (orthotopic tumours). Initial results of these studies are expected in Q317.

“These new results are very exciting and provide additional evidence that strongly points in favour of using whole-plant extracts over single cannabinoid molecules,” said Professor Sánchez. “We look forward to completing our next round of studies in coming months.”

Zelda Therapeutics (ASX:ZLD) shares closed a whopping 48.21% higher at $0.083 on 2 June, the day of the announcement.

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