The open-label mid-stage trial of SFX-01, which was launched in January 2017, was carried out in 46 patients with estrogen-positive (ER+) metastatic breast cancer.
SFX-01 is a synthetic and stabilized version of the naturally occurring plant compound sulforaphane, which is known to be an anti-cancer agent and for having neuro-protective characteristics.
The STEM trial had the objectives of assessing SFX-01’s safety and tolerability in combination with an aromatase inhibitor (AI) or tamoxifen or fulvestrant, and also for determining the clinical benefit rate (CBR) at 24 weeks.
For safety and tolerability, the primary endpoint was the number and severity of adverse events recorded after treatment with the investigational drug. Evgen Pharma said that the drug had a favorable side effect profile, especially in comparison with other cancer drugs.
For efficacy, the primary endpoint was defined as CBR at 24 weeks, which is the percentage of patients who showed an objective response with their tumor shrinking by at least 30% or having stable disease for at least 24 weeks.
The company said that 24% of patients showed a durable clinical benefit for at least six months, in spite of the late stage of disease and their established resistance to hormone therapy. This demonstrated conclusive evidence of anti-cancer activity, said Evgen Pharma.
STEM chief investigator Sacha Howell said: “We are very excited by the STEM trial results. This level of disease stabilisation, coupled with objective evidence of tumour shrinkage, bodes well for testing SFX-01 earlier in the treatment path.”
The clinical-stage company plans to advance SFX-01 into a randomized, double-blind, clinical trial for earlier stage patients as an adjunct to a second line hormone therapy to slow down onset of resistance.
Evgen Pharma CEO Stephen Franklin said: “We are absolutely delighted with the trial result and it has galvanised our enthusiasm and commitment to ensure SFX-01 continues its development in breast and other cancers.
“In the context of this particular patient group, the clinical benefit observed is very encouraging and we have a high level of confidence that it will perform even better when used to delay the resistance to a newly presented second-line hormone therapy.”