U.K. biotech Scancell ($SCLP) says it will need to delay the trial of its experimental skin cancer immunotherapy vaccine SCIB1-001 due to its meds batch going beyond its shelf-life.
The Phase I/II trial for the drug, which is targeting melanoma in 35 patients, began all the way back in 2010 and was expected to last only to last 6 months--but encouraging signals have seen the study extended by 6 years.
This has had the apparently unanticipated effect of the drug now unable to work, given that the stored treatment is “no longer within the original specification,” according to the AIM-listed biotech.
Scancell said it is “suspending dosing with the current clinical trial supplies of SCIB1 with immediate effect” as a result, and will need a specialist manufacturer to make more of the drug--a complicated process that could take 9 – 12 months.
When the new batch is made, Scancell said it will be used in a new study in combination with a checkpoint inhibitor (although just which one has not been named), as well as giving it to those patients currently in the long-term extension of SCIB1-001 who wish to continue receiving the drug.
Currently, 8 out of the 35 patients will be affected by the delay. But the company said this should not hit those patients’ outcomes.
“While it is expected that there will be a delay of approximately 9-12 months before the new SCIB1 material will be available for clinical use, it is anticipated that the anti-tumor response induced by SCIB1 should persist and eliminate any remaining tumor cells,” the biotech said.
A formal statement from the company added: “Further doses of SCIB1 have been given for added protection to ensure the immune cells continue to patrol for any emerging cancer cells; subsequent administration of the new SCIB1 material should reactivate these memory immune cells to eliminate any recurring tumours.”
The trials have been taking part across England in late-stage melanoma patients. Up until this announcement, 20 patients with resected tumours were still alive with 5 having progressed.
Dr Richard Goodfellow, CEO of Scancell, added: “Patient safety has always been our primary responsibility. Although we have seen no new adverse events it is unfortunate, but nevertheless appropriate, that we suspend dosing of SCIB1 at this time while we work as quickly as possible to secure new supplies of this promising potential treatment for melanoma.
“Starting further efficacy studies with SCIB1 is only possible due to the results we have seen so far in the long-running SCIB1-001 study and we would again like to convey our thanks to the patients in that trial for their participation and support over the past 6 years.”
But the market has reacted badly to the news and the delay, and by midday BST its shares had slumped by 19%.
SCIB1 is a plasmid DNA which encodes a human antibody molecule engineered to express two cytotoxic T cell epitopes derived from the melanoma antigens Tyrosinase-Related Protein 2 (TRP2) and gp100 plus two helper T cell epitopes.
Following immunisation, the engineered antibody is expressed and taken up by dendritic cells, resulting in the development of immune responses against tumour cells expressing the TRP2 and gp100 antigens.
There are already a number of immunotherapies already on the market for melanoma--which until 2011 had few options outside surgery and chemotherapy--with checkpoint inhibitors from Bristol-Myers Squibb ($BMY) in the form of Yervoy and more recently the major PD-1 blockbuster Opdivo, as well as Merck’s ($MRK) PD-1 drug Keytruda.
The immunotherapy cancer market for this new class of drug is expected to hit $35 billion by the middle of next decade.
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