The U.S. Food and Drug Administration (FDA) has rejected the approval of Cempra Inc.’s antibiotic for community-acquired bacterial pneumonia because of a lack of data on the drug’s effect on the liver and unspecified manufacturing issues.
Cempra received a Complete Response Letter (CRL) from the FDA Thursday saying that more research needs to be done before the drug solithromycin is approved. Shortly after Cempra received the CRL, the company’s stock experienced a drastic fall.
Before the letter was sent, shareholders were hopeful that the agency would approve the drug because the FDA hasn’t approved a drug for the treatment of bacterial pneumonia for decades. An independent FDA panel narrowly voted in favor of the drug 7 to 6 in November, but the concerns over data were too strong.
“Based on their review of the NDAs, the CRL stated that the FDA determined the risk of hepatotoxicity had not been adequately characterized,” said Cempra in a statement. “The FDA noted the size of the safety database is limited to 920 patients who received solithromycin at the proposed dose and duration, and is too small to adequately characterize the nature and frequency of serious hepatic adverse effects.”
Despite the fact that the Cempra data showed no evidence of acute liver injury, the FDA recommends Cempra conduct a study exposing around 9,000 patients to solithromycin to determine the occurrence of drug-induced liver injury with better accuracy.
What is Solithromycin?
Solithromycin is the descendant of a controversial drug called Ketek used to treat certain types of pneumonia caused by bacteria. However, the drug was discontinued after it was linked to serious and fatal liver problems.
Even without a case of serious liver injury, the FDA would likely require labeling of solithromycin to include information about the risk of hepatotoxicity. This would restrict the use to patients with limited therapeutic options.
Cempra Drug Also Rejected Over Manufacturing Issues
Along with limited data, the FDA mentioned unspecified manufacturing issues in its CRL. During recent inspections of manufacturing facilities, the FDA field investigator conveyed deficiencies to representatives at the facility.
The FDA has previously notified Cempra of poor manufacturing practices at Wockhardt, which is based in India. There are also manufacturing issues at Pfizer’s Hospira facilities. The company has already found another manufacturer in India called Uquifia to make the drug if necessary.
While specific details were not in the CRL, the manufacturing issues must be resolved before solithromycin is approved.
Path Forward For Cempra Unclear
The rejection of solithromycin is a huge blow to Cempra. The company will need to meet with the FDA to discuss the details of the recommended clinical safety study and how to resolve manufacturing problems.
“As the rates of antibiotic resistance continue to rise, there is an unmet medical need for new antibiotics to treat patients with CABP and Cempra is committed to working with the FDA to achieve the approval of solithromycin as quickly as possible,” David Zaccardelli, acting chief executive officer of Cempra, said in a statement.
While Cempra plans to continue pursuing the approval of solithromycin, the drug likely won’t be approved until at least 2018. The company will need to determine whether it’s financially viable to keep pursuing approval.
“With more than $225 million of cash on hand, patent protection for solithromycin through 2032 and a pipeline that includes fusidic acid and other potential programs for solithromycin, including an ophthalmic formulation, we have flexibility to determine the best course forward for solithromycin and Cempra,” Zaccardelli added.