FDA Slaps Clinical Hold on Concert Pharma (CNCE)'s Hair Loss Drug

The U.S. Food and Drug Administration (FDA) placed a clinical hold on Concert Pharmaceuticals (CNCE)’ CTP-543 Phase IIa clinical trial for alopecia areata, a common autoimmune skin disease that causes hair loss.

The FDA had previously given the go-ahead for the trial, but before patient dosing began, the FDA asked for some non-clinical toxicology studies to be reviewed. Safety concerns were not a problem. The company plans to submit the non-clinical reports as quickly as possible. The FDA has 30 days from receipt of the company’s response to notify Concert if the clinical hold is lifted.

Concert focuses on using deuterium chemistry to replace hydrogen molecules in drugs, resulting in longer-acting treatments. CTP-543 is a modification of ruxolitinib, a Janus kinase 1 and 2 inhibitor that is marketed in the U.S. by Incyte (INCY) under the trade name Jakafi for blood disorders. The drug has been used in academic settings to treat alopecia areata, including in an investigator-sponsored clinical trial.

In March, Vertex Pharmaceuticals (VRTX) acquired Concert’s cystic fibrosis (CF) drug candidate CTP-656. As was later revealed in filings with the U.S. Securities and Exchange Commission (SEC), Vertex attempted to acquire the company in November 2016, offering $250 million. However, Concert turned down the offer.

Concert argued that the deal "substantially undervalued the company as a whole." But the board then discussed the possibility of a more specific, limited deal involving CTP-656. Eventually, Vertex acquired the drug for $160 million upfront and $90 million in possible milestone payments.

CTP-656 is an investigational CF transmembrane conductance regulator (CFTR) potentiator. It is being developed as part of a once-daily combination regimen of CFTR modulators. CTP-656 is essentially the same drug as Vertex’s Kalydeco. The difference is that hydrogen atoms are replaced by deuterium atoms, which makes it last longer. CF patients take Kalydeco twice daily. Concert’s data indicates that CTP-656 could be taken once a daily. Deuterium, known as "heavy hydrogen" is a stable isotope of hydrogen.

Vertex plans to combine CTP-656 with tezacafator so that patients would only take one per day. Currently, Vertex has a combination of tezacaftor and Kalydeco in a late-stage clinical trial for a single tablet in the morning, but would also require a second dose of Kalydeco at night.

During Concert’s first-quarter financials earnings call on April 27, the company’s president and chief executive officer, Roger Tung, noted, "Last month, Incyte filed an IPR petition, which in essence challenges the validity of our patent covering CTP-543. We’ve anticipated that such a challenge might be raised. We’re preparing our response now and will file it within the statutory three-month response period. The Patent Trial and Appeal Board, or PTAB, will then have an additional three months to decide whether to grant or deny Incyte’s petition. If the PTAB institutes a review of our patent, we would expect a final PTAB decision in the fourth quarter of 2018. We’re confident in our patent’s validity and intend to vigorously defend it."

Concert’s CTP-543 for alopecia areata is in a competition to hit the market before Aclaris Therapeutics’ ATI-50001. Aclaris announced earlier this mount that it would start a mid-stage clinical trial the second half of this year.

On May 5, Aclaris announced that ATI-50001 had completed a Phase I clinical trial for alopecia areata. It was well-tolerated in 12 healthy volunteers and had a safety profile similar to placebo. The company is also planning to develop a topical formulation, ATI-50002, to treat alopecia areata, vitiligo and androgenetic alopecia.

Concert Pharmaceuticals shares are currently trading for $14.81. Shares traded at $16.05 on May 16 and a high of $18.43 on March 22.