Regeneron cites success of PhIII anti-NGF pain drug after big rival bails out

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Regeneron says that its anti-NGF pain drug fasinumab came through in a Phase II/III study for osteoarthritis patients, posting significant improvements on a key pain score. 

Once part of one of the most closely watched niche fields in R&D, the nerve growth factor antibody was put on ice 5 years ago after patients started blowing out their joints after beginning treatment. But developers were able to map a path forward that satisfied the FDA’s safety concerns, putting Pfizer’s ($PFE) tanezumab--partnered with Eli Lilly ($LLY) in a deal worth $1.8 billion--and Johnson & Johnson’s ($JNJ) fulranumab back on track alongside Regeneron.

Just a month ago, though, J&J tossed all rights to its drug back to Amgen ($AMGN), where it came from, writing off four big late-stage studies after describing the move as the result of a mere reprioritization of its assets.

Regeneron’s 16-week data on a monthly injection help underscore the promise of this class, though the data also include a strong placebo response. The four doses studied in the II/III trial reduced the baseline pain scores of patients by half or more. The placebo arm saw a drop of 2.25 points on a baseline score of 6.3, not as high as the drug arms but still significant, underscoring the problem that many pain drugs have with a placebo response.

The drug also posted a sharply higher set of adverse events for arthralgia, paraesthesia, hypoaesthesia and peripheral edema--raising the risk of neuro-musculoskeletal adverse events. And a close eye on patients’ joints led investigators to wash out 2% of screened subjects.

“While we are encouraged by the efficacy of the drug, safety questions remain--especially with dosing beyond 16 weeks,” noted Barclays’ Geoff Meacham this morning. “As a reminder, this trial dosed patients for 12 weeks, with primary efficacy measured at 16 weeks. Safety will continued to be examined through week 36, with patients off treatment. Recall, the company announced plans to proceed with a longer trial in February after discussions with regulators. This asset is not part of the antibody collaboration with Sanofi.”

The company is pursuing a 10,000-patient phase IIB/III safety study, Meacham added, which will look at the drug over longer time periods. “In addition to this trial, the company will need to complete a pivotal Phase III for regulatory approval.”

Given alarming levels of opioid addiction in the U.S., though, there’s a significant market waiting on a nonopioid like this.

“There is a real need for new, non-opioid pain therapies that can provide relief to patients without the toxicity and potential for abuse of currently available opioid treatments,” said Regeneron CSO George Yancopoulos in a statement. “We had previously evaluated an intravenous formulation of fasinumab in osteoarthritis patients, and this is our first trial of a convenient subcutaneous monthly regimen. We look forward to continuing to study the safety and efficacy of fasinumab in our Phase 3 program."

- here's the release