We all like to root for the underdog. Following an arid spell stretching over three decades that in 2017 led to the ouster of Immunomedics founder/CSO and his CEO wife, the company (and analysts) were hopeful the drug developer would finally win its first FDA nod for its treatment for a difficult-to-treat form of breast cancer. The management shakeup, at the behest of an activist shareholder campaign, had rejuvenated the company’s fortunes by attracting investment and ramping up the drug’s development. But the FDA on Thursday handed the biotech a rejection citing manufacturing issues, adding yet another delay to the regulatory timeline.
The New Jersey-based company’s shares plummeted about 33.5% in early Friday trading.
The drug — called IMMU-132 or sacituzumab govitecan — is an antibody drug conjugate (ADC) or an armed antibody which is designed to deliver a specific payload of a chemotherapy directly to a tumor, to reduce the toxicity associated with the conventional administration of chemotherapy. The FDA granted the drug priority review on the basis of data from an ongoing single-arm Phase II study in patients with metastatic triple-negative breast cancer (mTNBC) who have undergone prior therapy. Sacituzumab govitecan, which is also being tested in a confirmatory Phase III study in mTNBC patients, was expected to win accelerated approval on January 18. Analysts had suggested available mid-stage drug data indicated it was a significant improvement over standard-of-care and had assigned it peak sales expectations of $1 billion and more.
In its last update in December, Immunomedics reported data from the 108-patient mid-stage study — as assessed by independent review — demonstrated the drug induced partial or complete tumor shrinkage in 34% of patients, with a median duration of response of about 9 months.
To be sure, the company was not expecting the rejection. It hired a sales force back in November in anticipation of the January approval and told analysts in December that manufacturing issues the US health regulator had flagged in August had been since addressed.
In a December 20 note, Jefferies analysts said that while manufacturing issues could be a source of concern, they remained “confident in ‘132 as the company believes all issues have been resolved and it has invested heavily in the commercial infrastructure prior to approval. Additionally, we would highlight that IMMU has secured an agreement with Samsung Biologics as a secondary manufacturer…providing risk mitigation if issues cannot be resolved at current site.”
On Thursday, Immunomedics underscored the sacituzumab govitecan rejection had nothing to do with the drug’s clinical data.
“The issues related to approvability in the CRL were exclusively focused on Chemistry, Manufacturing and Control matters and no new clinical or preclinical data need to be generated,” Immunomedics chief Michael Pehl said in a statement, adding that the company intended to request a meeting with the FDA to better understand the agency’s requirements.
But with no light at the end of the government shutdown tunnel, who knows how long that will take.
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