Roche has pulled the plug on its collaboration with Inovio after stepping away from the development of the second candidate, the hepatitis B DNA immunotherapy INO-1800.

The companies signed a deal in 2013 giving the Swiss drugs giant exclusive access to two of Inovio's DNA-based immunotherapies - INO-1800 and INO-5150 for prostate cancer, the rights to both of which have now been returned.

Inovio said it would continue development of the drug independently, progressing the current Phase I study which is enrolling as planned in 30 clinical sites in the US and Asia-Pacific regions.

The trial is designed to evaluate the safety, tolerability, and immunogenicity of INO-1800, alone or in combination with INO-9112, Inovio's IL-12-based immune activator in adults with chronic hepatitis B infection. Enrollment should complete in the first half of 2017 with results expected sometime in the second half of the year, the firm said.

"While we acknowledge Roche's strategic decision in the area of hepatitis B, we are optimistic that our potent immunotherapy platform will make a difference in this globally important chronic viral infection, similar to what we have demonstrated in HPV-related disease," noted Dr Joseph Kim, Inovio's president and chief executive.

"Inovio was already managing the Phase I clinical trial so the study will continue on track without disruption."