BioWorld International Correspondent
LONDON - SR Pharma plc said its immune potentiator, SRL 172, failed in a Phase III trial in the treatment of non-small-cell lung cancer. Shares in the company fell by more than 70 percent, from £3.13 to 84 pence, when the results were announced last week.
Tom Lang, the company's business development director, told BioWorld International, "This is very, very disappointing news. It won't change what we are doing in other areas, but we will have to take stock in cancer.
"We can't decide that today," he said. "There is still other data, secondary endpoints, etc., that need to be analyzed over the next week or two. We have to try and see why the encouraging evidence [of efficacy] in Phase II wasn't seen in this trial."
The study was held across Europe in 418 patients, and Lang said the data also would be broken down by individual countries.
The primary endpoint of the yearlong trial was to show that administering SRL 172 as an adjunctive treatment to standard chemotherapy extended survival. In the first 15 weeks the rate of deaths in patients receiving chemotherapy alone was significantly higher, but in the main phase the death rates came together, so overall there was no statistically significant improvement in survival rates. In the Phase II trial there was a 29 percent survival benefit in patients receiving SRL 172.
SR Pharma, based in London, is currently awaiting the results of a Phase II trial of SRL 172 in renal cancer, due at the end of May, and of a Phase I/II trial in prostate cancer. A further, investigator-led trial in small-cell lung cancer also is in progress, and a trial in malignant melanoma is being planned. Lang said there was no reason to stop the ongoing trials.
SRL 172 failed in 1999 in a company-sponsored Phase III trial in tuberculosis. However, a subsequent trial sponsored by the U.S. National Institutes of Health showed that TB patients treated with SRL 172 in addition to standard antibiotics had a better overall quality of cure at 12 months. The compound is also in trials for allergic disorders including asthma and atopic dermatitis.
"We as a company still believe that SRL 172 has significant potential, but of course if you can't produce definitive clinical data, the product won't reach the marketplace," said Lang.
SR Pharma had £11 million (US$15.75 million) cash at the end of December.