Sinovac, Merck and Other Companies Pause Some Clinical Programs


One day after Pfizer and BioNTech electrified the world with news the mRNA vaccine candidate the companies are developing against COVID-19 demonstrated 90% efficacy after an interim analysis, another vaccine developer, Sinovac, stumbled.

CNN reported that health authorities in Brazil suspended ongoing trials of Sinovac’s vaccine candidate, CoronaVac, in that country following reports of serious adverse events. Citing a note from Brazil's National Health Surveillance Agency, CNN reported that an Oct. 29 incident “led to a decision to suspend the trial in order to better evaluate the data and assess the risk.” The Brazilian health authority did not specify what kind of adverse event was reported or where it took place due to privacy concerns. The Brazilian Butantan Institute in Sao Paulo, which is conducting the study of the Sinovac vaccine, will hold a press conference today, according to the report.

Sinovac, one of China’s largest vaccine developers, said in a statement on its website that the serious adverse reaction is not related to the vaccine.

“After communicating with the Brazilian partner Butantan Institute, we learned the head of Butantan Institute believed that this serious adverse event (SAE) is not related to the vaccine.  Sinovac will continue to communicate with Brazil on this matter.  The clinical study in Brazil is strictly carried out in accordance with GCP requirements and we are confident in the safety of the vaccine,” Sinovac said this morning.

Last month, AstraZeneca’s COVID-19 vaccine study in Brazil was marred by reports of a patient death.

Brazil has the third highest number of reported infections of COVID-19 following the United States and India. According to the Johns Hopkins COVID-19 dashboard, there have been more than 5.6 million reported infections and 162,628 related deaths.

Sinovac isn’t the only company this week to see a pause in a clinical study. This morning, Merck announced it was halting a Phase III study assessing its vaunted checkpoint inhibitor Keytruda with Bristol Myer Squibb’s Yervoy as a potential first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors express PD-L1 with no EGFR or ALK genomic tumor aberrations. The decision to halt the trial followed the recommendation of an independent Data Monitoring Committee, which determined the benefit/risk profile of the combination did not support continuing the trial.

At an interim analysis, the combination of Keytruda and Yervoy showed no incremental benefit in overall survival or progression-free survival, which were the study’s dual primary endpoints, compared to Keytruda alone. While there were no new safety signals from Keytruda as a monotherapy, Merck said the combination treatment was associated with a higher incidence of adverse events.

Massachusetts-based Voyager Therapeutics also announced a pause in a clinical study – the company’s second pause in a month’s time. On Monday, Voyager said the Independent Data Monitoring Committee attached to its Parkinson’s disease study recommended a pause pending a review of additional data. The RESTORE-1 Phase II study is assessing VY-AADC (NBIb-1817) as a one-time AAV-based gene therapy encoding the gene for human AADC that is designed to help produce the AADC enzyme in brain cells where it can convert levodopa to dopamine. VY-AADC is administered into the brain using magnetic resonance imaging-facilitated targeted delivery.

The study was halted following the review of patient imaging data. Voyager said trial sites participating in RESTORE-1 are not currently screening and enrolling patients as a result of the COVID-19 pandemic. In response to the DSMB’s recommendation, Voyager and Neurocrine have decided to delay the planned resumption of patient screening in the RESTORE-1 trial until the DSMB is able to complete its evaluation.

For Voyager, the pause in the RESTORE-1 study comes about a month after the company was forced to pause its experimental gene therapy treatment for Huntington’s disease. The U.S. Food and Drug Administration placed a clinical hold on the company’s Investigational New Drug (IND) application for VY-HTT01 for the treatment of Huntington’s disease. The FDA placed the hold onto the program hold pending the resolution of certain chemistry, manufacturing and controls matters.

Praxis Precision Medicines also reported the FDA placed a clinical hold on its IND for a major depressive disorder treatment. This morning, Praxis said the FDA did not provide a reason for its decision to place the hold on the planned Phase II/III study of PRAX-114 for MDD. Praxis said it intends to receive final comments from the FDA within 30 days and intends to work closely with the agency to understand and resolve key issues for the study.

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