Chimerix’s first approved drug had several high-profile setbacks, resulting in a much narrower regulatory approval than initially hoped. Now, the company is selling the rights to the drug to Emergent BioSolutions as a way to raise capital as it looks ahead to a pivotal late-stage trial of its lead asset, which treats a rare form of cancer.
The drug Emergent is acquiring, Tembexa, is officially recognized Last June as a treatment for smallpox infection. In collaboration with the Biomedical Advanced Research and Development Authority (BARDA), Chimerix developed the antiviral drug as a medical countermeasure to prevent smallpox from being used as a biological weapon. For the app, the drug’s customer base is essentially one customer — BARDA. So far, Durham, North Carolina-based Chimerix has not recorded sales of the approved drug with the agency.
Emergent has agreed to pay Chimerix $225 million at closing and an additional $100 million in up to four milestone payments of $25 million, under the terms of the deal announced Monday. Each of these milestone payments is related to BARDA’s exercise of a purchasing option on Tembexa. Chimerix said it is negotiating the procurement contract with BARDA and will continue to lead the process until completion.
If circumstances were different, Tembexa might be more widely used as a broad-spectrum antiviral. The drug, known under the name brincidofovir for much of its history, is expected to offer an advantage over the injectable Gilead Sciences antiviral cidofovir. In addition to a pill formulation that’s easier for patients to take, Chimerix wants brincidofovir to be safer than the Gilead drug, which has been linked to kidney damage. The first indication targeted by Chimerix is the treatment of cytomegalovirus infection in transplant patients.
In 2009, early in brincidofovir’s clinical development, Chimerix also began offering the drug under the FDA’s Compassionate Use Program, which allows patients with no treatment options to access the experimental treatment. As the antiviral drug progressed in clinical trials, Chimerix closed its compassionate use program to focus on pivotal testing of the drug in support of an application seeking FDA approval.But in 2014, Chimerix found itself in a National debate on ‘right to try’ experimental drugsVirginia boy Josh Hardy contracted adenovirus after cancer treatment and bone marrow transplant. His doctor recommended treatment with brincidofovir in compassionate cases. The debate over access to the still-experimental drug has drawn widespread attention on national news and social media. The company’s CEO even received death threats.
Chimerix found a way to give the drug to Hardy, but didn’t use it out of compassion. The company worked with the FDA to design an open-label clinical trial to test brincidofovir against adenovirus. Hardy was the only patient. He reportedly responded to treatment and was able to go home.
Brincidofovir has performed poorly in late-stage clinical development. In 2015, the drug Phase 3 study in cytomegalovirus infection failedThis leads to the company Stop two additional late-stage studies for drugs. The remaining drugs are the BARDA-funded smallpox program. The study continues, but the Phase 3 failure of brincidofovir in cytomegalovirus infection essentially marked the end of Chimerix as an antiviral drug developer.
In 2019, Chimerix licensed global rights to brincidofovir to SymBio Pharmaceuticals to develop all human indications except for orthopoxviruses such as smallpox. Tokyo-based SymBio paid $5 million up front and could pay up to $180 million more if the drug hits regulatory and commercial milestones. If SymBio commercializes the drug, the deal would allow Chimerix to receive royalties from sales. Under the terms of the deal with Emergent, Chimerix is eligible to receive up to $12.5 million in regulatory milestones from SymBio’s collaboration with the drug.
The Tembexa deal could close this quarter, Chimerix and Emergent said. When it happens, it will be the necessary cash injection.in its report First Quarter 2022 Financial Results, Chimerix said it has $53.4 million in capital to fund its operations. The biotech’s lead program, ONC201, is preparing to advance pivotal testing in H3-K27M mutant glioma, a rare brain tumor that develops in children. This cancer cannot be treated with chemotherapy and is difficult to remove with surgery. Chimerix said in its quarterly report that it expects to begin clinical trials of ONC201 later this year. To conserve cash and focus its resources on its lead drug candidate, Chimerix terminated work on DSTAT, which has reached Phase 3 testing in acute myeloid leukemia. CEO Mike Sherman said in a statement that the decision followed an internal pipeline review.
“This narrower focus on developing resources will ensure that we optimize our execution to bring ONC201 to patients as quickly as possible,” he said.
Photos by Flickr users Paul Joseph through Creative Commons license
