Dynavax had said it was the last throw of the dice for its hepatitis B vaccine, Hepislav-B – the data pointed to it entering the market as best-in-class but it had received one knock-back after another, culminating in a final three month user fee action data delay.

It was first rejected in 2013 and then later in 2016, both times requiring more data on safety and post-marketing plans. In the end, the FDA agreed that the data supported an approval and it proved that persistence does pay off for Dynavax.

The positive decision means that the company now expects to begin selling the vaccine in the first-quarter of 2018. Its vaccine will come up against some big pharma competition, with the two largest vaccines in the area being GSK’s Engerix-B and MSD’s Recombivax.

Dynavax needs a serious pay-off on the vaccine, having accumulated a significant debt for a relatively small company, having built up a deficit of $880 million.

In better news for the company, analysts have predicted that the vaccine could reach peak sales of approximately $600 million. This relies on it ousting Engerix-B from its position as leader in the area.

However, the company remains confident it can based on several advantages: it boasts stronger data on protection offered, with a 95% rate of protection comparing favourably against 81% for Engerix-B. Beyond this, in a sub-group of type 2 diabetes sufferers, it offered a 90% rate of protection against 65% for Engerix-B.

"Hepislav-B is the first FDA-approved product for Dynavax and demonstrates our ability to develop innovative products and progress them from discovery to commercialisation," said Eddie Gray, chief executive officer of Dynavax. "We would like to thank the many study participants and clinical trial investigators who contributed to the development of Hepislav-B. We expect that it will become an essential tool in the public health community's fight to prevent hepatitis B, and we look forward to making Hepislav-B available to clinicians and their adult patients."

The next step for the company is to launch its sales force, which will number around 50 sales staff. This may seem to diminutive compared to the force of big pharma’s capabilities but Gray has insisted that this is standard for such a market.