Protalix BioTherapeutics of Carmiel, Israel, released a new analysis of its early-stage PRX-115 gout-drug study on November 9, reporting that participants with longer-lasting measurable drug levels also maintained lower blood uric acid for longer. The individual-participant analysis supports the company’s work on less frequent infusions, but is not a new Phase 2 result or proof of improved symptoms in people with uncontrolled gout.
The company’s announcement covers three higher-dose groups from its Phase 1 single-dose study: 18, 24 and 36 milligrams, with six participants in each group. These adults had elevated plasma uric acid and received a single infusion, with follow-up lasting 85 days.
Protalix said drug exposure increased with dose and persisted longer at higher doses. Participants whose PRX-115 concentrations remained measurable for longer also kept plasma uric acid below the therapeutic target for longer; declining drug concentrations coincided with a gradual recovery in uric acid levels. The analysis examines how drug levels and the biological response relate over time.
The headline finding that mean plasma uric acid stayed below 6.0 milligrams per deciliter for up to 12 weeks after a 36-milligram infusion was previously reported in 2024. What the company is adding now is individual-participant information about that relationship, not a newly completed trial showing 12-week benefit. A group average also does not mean every participant maintained that response.
Safety remains part of the picture. Protalix said the Phase 1 study’s related adverse events were mostly mild to moderate and transient, but one participant had an anaphylactic reaction that resolved. The company’s account says the reaction occurred six minutes into an infusion after about 5% of the planned dose; antihistamine and steroid premedication was subsequently given to all participants. No other serious adverse events were reported, according to the company.
PRX-115 is a plant-cell-produced, modified uricase enzyme being developed for uncontrolled gout. Gout involves elevated uric acid and can cause recurring inflammatory arthritis and joint damage. The treatment’s proposed value is sustained uric-acid lowering with fewer infusions, rather than simply a larger short-term drop in the laboratory measurement. Whether that approach delivers a useful balance of benefit, convenience and safety still needs testing.
The ongoing Phase 2 RELEASE study is double-blind and placebo-controlled, with five planned treatment groups of 30 patients each. It tests 36 milligrams every four weeks without methotrexate, every four, six or eight weeks with methotrexate, and placebo. The main endpoint is the proportion of patients whose serum uric acid remains below 6.0 milligrams per deciliter for at least 80% of the time during the sixth month.
Protalix expects top-line RELEASE results in the second half of 2027. That is a company forecast, not a completed finding. The new analysis does not establish which repeated-dose schedule will work best, whether the candidate is better than existing treatments, or whether regulators will approve it.
The analysis is scheduled for a poster presentation at the American College of Rheumatology’s meeting in Orlando, Florida, on November 10, from 10:30 a.m. to 12:30 p.m. Eastern time. The November 9 announcement previews that presentation; it does not mean the scheduled poster session has already taken place.
For patients and investors following the program, the distinction is between a small early study’s biological signal and the larger treatment question still ahead. The Phase 2 results will be needed to assess sustained response under repeated dosing and add safety information. The release did not provide those outcomes, and the small single-dose analysis cannot settle them.
JBizNews Desk | Carmiel, Israel
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