4D pharma PLC (AIM:DDDD, NASDAQ:LBPS) soared about 30% in London trading after the company said it had hit its primary efficacy target in a phase I/II trial of one of its lead assets in kidney cancer.
MRx0518 was used in combination with KEYTRUDA, the Merck blockbuster, which is a part of a class of drugs called immune checkpoint inhibitors (ICIs).
While very effective for certain patients, the impact of these types of treatments can wane.
4D was focused on a group of heavily-pretreated metastatic patients (so, late stage) who had previously benefited from ICIs.
The hurdle it needed to overcome was to show clinical benefit, defined as complete response, partial response, or stable disease, in three out of 30 extremely sick trial participants for at least six months.
Part B of its study of people with renal cell carcinoma (RCC) revealed that four of the 16 'evaluable' patients achieved clinical benefit. Each of them saw the disease stabilise for at least six months.
"Today's results in renal cell carcinoma, meeting the predefined primary efficacy endpoint early in this difficult to treat population, marks another important step forward for MRx0518 and the increasing importance of the microbiome in cancer treatment," said Dr Alex Stevenson, 4D’s chief scientific officer.
"Meeting the primary efficacy endpoint for this group is crucial for the future development of MRx0518, and these data are highly informative for our strategy going forward as we determine next steps in RCC."
To date, the kidney cancer cohort evaluation has enrolled 20 people, while the wider Part B assessment has begun treating 47 people with solid tumours, including non-small cell lung cancer, bladder cancer, and head and neck squamous cell carcinoma.
4D said MRx0518 continues to be safe and well-tolerated.
It also told investors it will discuss the next steps with its advisory board.
The company is a pioneer in microbiome-focused drugs that use good human bacteria to treat illness.
The shares traded up 13.2 pence to 58p apiece.
(Updates with share price move.)