- Ironwood Pharmaceuticals intends to push a high dose of its heartburn drug into Phase 3 testing following initial mid-stage data showing the drug's efficacy.
- The Phase 2b trial enrolled nearly 300 patients with gastroesophageal reflux disease (GERD) who weren't adequately responding to standard of care proton pump inhibitors (PPIs). All participants stayed on PPI therapy during the study, but those who received a 1,500 mg regimen of Ironwood's IW-3718 demonstrated a 58% reduction in heartburn severity, the study's primary endpoint, versus a 46% reduction for those in a placebo arm.
- Investigators also tested two other regimens, 500 mg and 1,000 mg doses, of IW-3718, but those lower doses didn't individually meet the primary endpoint. Ironwood stock opened 4% down to $17.80 on Thursday, and dropped further in morning trading.
Other topline data showed that nearly 53% of patients on the 1,500 mg regimen had at least 45% reductions in their heartburn severity during at least four of the trial's eight week duration, while just 38% of patients taking PPIs alone signaled the same improvement.
In addition to meeting the primary endpoint, the 1,500 mg dose also appeared to lower regurgitation. Patients on that treatment showed a 55.4% mean decrease in regurgitation from baseline versus 38% for those not taking Ironwood's drug.
"To me, [these results are] very encouraging, not just in heartburn severity relief, but for the very first time we're seeing a really significant improvement in regurgitation, which is often one of the primary complaints these people have," Ironwood's Chief Commercial Officer Tom McCourt said during a July 20 investor call.
Should Ironwood's drug gain favor with regulators, it could bring in much-needed funds for the company. Market intelligence firm Grand View Research, for example, expects the global GERD drug space to reach $4.3 billion by 2025, according to a February report. Currently, the condition is largely treated by low cost, over-the-counter products like Nexium (esomeprazole).
The drugmaker had only $289,000 in net product revenues during the first quarter, and most of its income — about $52 million — came from collaborative arrangements. Ironwood has two marketed products — Linzess (linaclotide), which it partners on with Allergan, and Zurampic (lesinurad), though the later drug doesn't contribute almost anything to boost bottom lines. Ironwood also helps promote Allergan's irritable bowel drug Viberzi (eluxadoline).
"So as I look at the market opportunity in front of us — you look at the size of the market, the fact that these patients are very motivated, highly compliant and very active, I'm very much looking forward to taking this to market," said McCourt.
One element weighing on investor minds, though, looks to be the size of the 1,500 IW-3718 dose. Ironwood said patients take three pills in the morning and three at night. But as the industry is well aware, adherence tends to diminish as regimens get larger or more complicated. Ironwood said the treatment was well-accepted by over 80% of trial participants.