Switzerland-based drugmaker Roche has described its $5.7bn hostile offer for US gene sequencing company Illumina as "full and fair", confirming that it does not plan to increase its bid.

The bid values Illumina’s shares, of which Roche currently owns a limited number, at $44.50 each.

Roche launched its bid for Illumina as the company hopes to progress into the gene technology field, with Roche’s cancer drug portfolio expected to benefit greatly from gene analysis and sequencing. The current offer price represents an 18% increase over Illumina’s closing price on Tuesday and is 60% more than the price before rumours of a bid surfaced.

The hostile bid comes after Illumina expressed an unwillingness to negotiate, with Roche financial chief Alan Hippe adding, "Roche has made multiple efforts to engage with Illumina in order to reach a negotiated transaction, but Illumina has been unwilling to participate in substantive discussions."

Roche hopes to finance the deal, which would be the largest since the company’s $47bn acquisition of Genentech, through available cash and borrowings from credit facilities. Illumina responded to the bid by urging shareholders not to act until a recommendation from the board had been made.