Illumina urges shareholders to reject $6.5-billion buyout by Roche Illumina Inc. in San Diego urged its shareholders Monday to reject a sweetened buyout offer from Swiss drug maker Roche, saying the $6.5-billion deal still undervalues the maker of genetic analysis instruments. Illumina Chief Executive Jay Flatley called the deal "opportunistic" and said his company is poised to deliver better returns through higher sales and profits. Roche Holding did not immediately comment on Illumina's statement. Illumina shares fell $1.24, or 2.4%, to $51.73 after word of the latest rejection. Roche proposed to buy Illumina in January for $44.50 per share, or about $5.7 billion. Roche said the deal would strengthen Roche's position in life sciences diagnostics because its technologies are complementary with Illumina's. Illumina's board unanimously turned down Roche's offer, saying it was "grossly inadequate" and that shareholders should not tender their stock to Roche. Last week, Roche raised its offer to $51 per share, or about $6.5 billion, an increase of almost 15%. Earlier Monday, Illumina said that its first-quarter revenue will be about $270 million on strong demand for its research instruments. The estimate tops Wall Street expectations. The company also said that it expects its adjusted earnings for the quarter will match or beat expectations. Analysts expect earnings of 31 cents per share on revenue of $258 million, according to a survey by FactSet. Illumina makes equipment that biotechnology researchers can use to sequence genes or do other tasks.