Regeneron and Teva’s fasinumab hit with FDA clinical hold

Drug development partners Teva ($TEVA) and Regeneron ($REGN) have seen a midstage study of their experimental pain med fasinumab put on a clinical hold by the U.S. regulator due to safety concerns.

The pair’s anti-NGF fasinumab was being studied in a Phase IIb trial in chronic low back pain, among others tests including osteoarthrosis pain.

This study has now been placed on clinical hold by the FDA, with the agency asking the partners for “an amendment of the study protocol” after seeing a case of adjudicated arthropathy (a disease of the joint) in a patient receiving high-dose fasinumab, who had advanced osteoarthritis at study entry.

Since the hold was placed, Regeneron and Teva said in a statement that they have “completed an unplanned interim review of results” and have now stopped dosing in the study.

Their analysis showed “clear evidence of efficacy with improvement in pain scores in all fasinumab groups” when compared to placebo at the 8- and 12-week time points, they said, adding that safety results “are generally consistent with what has been previously reported with the class.”

It said that patients will continue to be followed for up to 36 weeks.

As a result of this hold, both said they would now set about designing a pivotal Phase III study in chronic low back pain that specifically excludes patients with advanced osteoarthritis in the hope this was a one-off related to this disease. 

“We are making data-driven decisions on Phase III fasinumab dosing that we believe will maximize potential benefit for patients in need, while minimizing the likelihood of side effects,” said George Yancopoulos, CSO at Regeneron.

“We look forward to working with global health authorities to advance this important investigational therapy for patients with often difficult-to-treat osteoarthritis pain and chronic low back pain.”

“We believe fasinumab represents an important potential innovation for patients with osteoarthritis pain and chronic low back pain who currently have clear unmet need and limited treatment options,” added Michael Hayden, president of global R&D and CSO at Teva.

When an ongoing FDA-approved test is placed on clinical hold, no new subjects may be recruited to the study and placed on the investigational drug. The regulator also says that patients already in the study “should be taken off therapy involving the investigational drug unless specifically permitted by FDA in the interest of patient safety.”

Back in May, the two posted positive data from a Phase II/III study for osteoarthritis patients that saw it notch significant improvements on a key pain score.

But in updated data, also shared today, the two said this study also showed some safety signals, with a higher rate of patients experiencing arthropathies in the higher dose groups of its med.

“Based on these data, the companies are planning to advance only lower doses in the ongoing fasinumab osteoarthritis pivotal Phase III program, subject to discussion with the FDA and other health authorities,” they added.

The anti-NGF field has seen safety setbacks before, when around 5 years ago patients started blowing out their joints after beginning treatment. This was addressed however with later research restarting--and although a few Big Pharmas pulled out of development, Teva, Regeneron, Lilly ($LLY) and Pfizer ($PFE) pushed on with testing.

This also comes a month after Teva said it would pay $250 million to help finish off mid- to late-stage work and then team up on selling with Regeneron for fasinumab.

Lilly and Pfizer restarted trials of their tanezumab anti-NGF candidate last year in the wake of the relaxation of the FDA's original 2011 clinical hold, focusing on osteoarthritis, chronic lower back pain, and cancer pain indications.

Given the sheer scale of opioid abuse and the need for new options, analysts have previously predicted that safe and effective NGF inhibitors could become a multibillion-dollar market opportunity.

Teva and Regeneron were down by 1.8% and 1.9% this morning ET on the news.