Shares of Myovant Sciences (MYOV) had crashed by 23.4% as of 11 a.m. ET on Tuesday. The steep decline came after the company and its partner, Pfizer (PFE -0.61%), announced that the Food and Drug Administration (FDA) had identified deficiencies in the Supplemental New Drug Application (sNDA) for Myfembree in managing moderate-to-severe endometriosis pain.
The FDA had previously established a PDUFA date of May 6 to complete its review of the sNDA for Myfembree. This issue may set the schedule back, but the regulator stated in its letter to Myovant and Pfizer that it hasn't made a final decision on the supplemental approval.
Investors reacted so negatively to the news because Myovant was counting on a May U.S. launch of Myfembree in the endometriosis indication. The FDA approved the drug as a treatment for heavy menstrual bleeding associated with uterine fibroids in May 2021.
But Myovant isn't solely dependent on Myfembree. The company's top-selling product is the prostate cancer drug Orgovyx. Also, it's not yet known how extensive the deficiencies were in the Supplemental New Drug Application for Myfembree. The agency hasn't yet provided details, other than to say that the issue or issues in question "preclude discussion of labeling and/or post-marketing requirements and commitments at this time."
Myovant and Pfizer said in a press release that they will "work with the FDA to determine next steps" regarding the sNDA for Myfembree. This likely isn't the end of the road for the drug in treating pain associated with endometriosis.