The patent – which covers a method of producing the active pharmaceutical ingredient (API) that contains fewer transhalogenated impurities than commercial supplies – will allow Provectus to seek licensing deals in China, according to CTO Eric Wachter.
“As we discuss with Chinese interests licensing PV-10 for other indications, it is important that we defend our intellectual property in this way” he said, adding that “we will continue to protect our stockholders’ interests in this way as we seek out partners globally.”
Provectus was issued with a US patent for the same synthesis method in 2013, which meant it met with International Conference on Harmonisation (ICH) guidelines on API production for Phase III trials.
PV-10 completed a single, open-label Phase II melanoma trial in 80 metastatic melanoma patients in 2012. The drug achieved a 51% overall response rate in lesions that were directly injected and a third of patients showed shrinkage in bystander tumors.
Since then, Provectus has repeatedly signaled its intention to begin a Phase III programme. However, while a study is registered on Clinicaltrials.gov website it has not begun enrolling patients.
Melanoma market
The melanoma market has changed in the two years since the end of the Phase II study. In 2011, Bristol Myers Squibb’s Yervoy (ipilimumab) was approved for melanoma.
Also that year, Roche had Zelboraf (vemurafenib) approved to treat skin cancers caused by a mutation of the BRAF gene. In 2013 the agency cleared two similar mutation-targeting skin cancer drugs made by GSK.
The pace of new melanoma drug approvals has not slowed down. Last September Merck & Co’s monoclonal antibody Keytruda (pembrolizumab) was cleared for skin cancer by the FDA.
The Merck drug – which sells for $150,000 per patient per year - belongs to a new class of therapeutics called PD-1 inhibitors that stimulate immune cells to attack tumours by blocking a protein the immune system would otherwise recognize as “self.”
The FDA approved a second PD-1 inhibitor in December, clearing Bristol-Myers Squibb’s Opdivo (nivolumab) for the treatment of advanced melanoma. The drug costs $143,000 for a one year course according to a report in the Wall Street Journal.