Another proxy advisory firm has given its support to the board at Illumina in its long-running battle to prevent Roche taking control of the US gene sequencing specialist.

Glass Lewis has followed in the footsteps of Institutional Shareholder Services and Egan-Jones in advising investors to reject Roche's $51.00 per share offer, which values Illumina at about $6.60 billion. In a report, Glass Lewis says the Swiss major's bid to get its nominees elected to the Illumina board at the latter's annual general meeting on April 18 "is intended to serve as little more than additional pressure to complete the transaction on Roche's terms, irrespective of whether they appropriately reflect Illumina's forward value or the board's ability to execute the company's stand-alone business plan in the current operational climate".

The report adds that "we find no cause for shareholders to support Roche's candidates, nor do we find any reason for shareholders to accept such an expeditious engagement as appropriate in the context of multi-year lows in share price and valuation for Illumina".

The San Diego-based group's chief executive Jay Flatley said "we are very pleased that all three of the leading proxy advisors…have now recommended that their clients support the re-election of Illumina’s slate of directors and vote against all of Roche’s proposals" at the AGM. He added that “the simple fact remains that Roche’s unsolicited offer clearly undervalues Illumina and that our highly-qualified and experienced directors are best positioned to create value".

Mr Flatley concluded by saying that the board is confident stockholders "will reject Roche’s hostile and opportunistic efforts to acquire Illumina at a grossly inadequate price".

At time of writing, Roche had yet to respond but earlier this week, chief executive Severin Schwan said his firm "firmly believes that our present offer is more than adequate to serve as a basis for negotiation [and] we remain willing to consider additional value if given the opportunity to enter discussions and perform due diligence". Most analysts expect Roche to sweeten its offer and ultimately win the day, though for the moment Illumina's board is in the lead.