Sophiris Bio is adamant that it’s going to advance its lead drug topsalysin into section 3 testing, after a second dose confirmed no extra profit in a prostate cancer trial.
The firm insists that the midstage data offered after a single administration of the drug is sufficient to warrant a late-stage program. Shares within the firm plunged 40% on the again of the brand new findings, nonetheless, suggesting traders have been hoping re-treatment would add to its efficacy.
Topsalysin (PRX302) is being developed as a therapy for localized (stage I or II) prostate cancer that’s solely activated within the presence of prostate particular antigen (PSA), related to prostate cancer and benign prostatic hyperplasia (BPH).
It is run by injection instantly into the prostate tumor, and within the presence of PSA binds to cancer cells and kind a pore throughout their membrane, inflicting them to rupture. It’s designed to kill tumors with out affecting healthy prostate tissue.
In the sooner readout from the phase 2b trial, 10 out of 37 sufferers handled with drug had a medical response six months after a single administration of topsalysin, with six of them seeing the full destruction of the tumor. Now, it says that “additional benefit was not observed on targeted biopsy six months after re-treatment” in sufferers who confirmed no response to the preliminary dose.
Piper Jaffray analyst Christopher Raymond says the six-month data with the drug stays “compelling” and he thinks the stock might recuperate on future catalysts akin to settlement on a section 3 trial protocol.
The newest share crash comes after a difficult few months for Sophiris and the topsalysin program which have induced its shares to yo-yo. The biotech halted affected person dosing in June after a affected person dying, but restarted trials a few months later after an investigation discovered that it was unrelated to the drug or administration process.
The lead investigator within the trial, Professor Mark Emberton M.D. of University College London (UCL) within the U.Okay., mentioned: “We remain encouraged by both the safety and biopsy data from the first administration of topsalysin and are working with Sophiris to design a protocol for a potential phase 3 registration study using a single administration of topsalysin.”
Sophiris’ CEO Randall Woods says the corporate is within the last phases of finalizing the design for the pivotal trial and will probably be submitting it to regulators, first within the E.U. after which within the U.S., for suggestions.
The newest readout has some extra outcomes that Sophiris reckons again up its optimism for a optimistic section 3 final result. Follow-up biopsy exams reveal that 15 of the 37 sufferers (41%) had a partial response that was nonetheless “clinically significant”, and fewer than a 3rd (32%) had no response to the drug. The therapy was well-tolerated by sufferers all through the research, in accordance to the biotech.
“The outcomes from the second administration on no account impacts our pleasure about topsalysin as a possible focused focal remedy in localized prostate cancer,” says Emberton. Around two thirds of newly-diagnosed prostate cancer sufferers have stage I or II illness.
Topsalysin additionally met its endpoints in a 2015 section 3 research in 479 BPH patients, bettering signs over 12 months.