The 212.0 percent increase in Molecular Diagnostics sales, excluding the effect of foreign exchange, was driven by demand for Abbott’s laboratory-based molecular tests for COVID-19 on its m2000 and Alinity m platforms as well as growth in the base business from the continued roll-out of the Alinity m platform. Molecular Diagnostics COVID-19 testing-related sales were approximately $310 million in the first three months of 2021. In March 2021, Abbott received an EUA in the U.S. for its multiplex molecular test on its Alinity m system to detect COVID-19, influenza A, influenza B, and respiratory syncytial virus (RSV) in one test. In the first three months of 2021, Molecular Diagnostics sales increased 33.9 percent, excluding COVID-19 testing-related sales, and increased 31.5 percent excluding the impact of foreign exchange and COVID-19 testing-related sales.
In Rapid Diagnostics, sales increased 295.0 percent, excluding the effect of foreign exchange, due to strong demand for Abbott’s COVID-19 tests on its rapid testing platforms including the Panbio system, the ID NOW platform, and the BinaxNOW COVID-19 Ag Card test. Rapid Diagnostics COVID-19 testing-related sales were approximately $1.8 billion in the first three months of 2021. In January 2021, Abbott received CE Mark for two new uses of its Panbio rapid antigen test: asymptomatic testing and self-swabbing under the supervision of a healthcare worker. On March 31, 2021, Abbott announced that it had received an EUA in the U.S. for its over-the-counter, non-prescription BinaxNOW COVID-19 Ag Self Test for individuals with or without symptoms. In the first quarter of 2021, Abbott also received EUAs that allow the non-prescription use of the BinaxNOW COVID-19 Ag Card Home Test and the BinaxNOW COVID-19 Ag Card test for professional use for individuals with or without symptoms.
Excluding the effect of foreign exchange, total Medical Devices sales grew 8.8 percent driven by double-digit growth in Diabetes Care and Structural Heart as well as growth in Electrophysiology and Rhythm Management. Growth in Diabetes Care sales was driven by continued growth of FreeStyle Libre®, Abbott’s continuous glucose monitoring system, internationally and in the U.S. FreeStyle Libre and Libre Sense™ sales totaled $829 million in the first quarter of 2021, which reflected a 29.8 percent increase, excluding the effect of foreign exchange, over the first three months of 2020 when Libre sales totaled $604 million. Libre Sense, which received CE Mark in the third quarter of 2020, is Abbott’s glucose sport biosensor specifically designed for athletes.
While procedure volumes across Abbott’s cardiovascular and neuromodulation businesses were negatively impacted early in 2021 by elevated COVID-19 case rates in certain countries, including the U.S., volumes improved over the course of the quarter for many products. Growth in Structural Heart was broad-based across several areas of the business, including TriClip®, the world’s first minimally invasive, clip-based device for repair of a leaky tricuspid heart valve which was launched in Europe in May 2020, and MitraClip®, Abbott’s market-leading device for the minimally invasive treatment of mitral regurgitation (MR), a leaky heart valve. In January 2021, the U.S. Centers for Medicare & Medicaid Services expanded reimbursement coverage eligibility for MitraClip.
Excluding the effect of foreign exchange, the 6.2 percent decline in Heart Failure sales reflects fewer left ventricular assist device (LVAD) procedures as such procedures, which require a stay in the hospital’s intensive care unit, continued to be negatively impacted by the COVID-19 pandemic during the first quarter of 2021. The sales decline also reflects the initial spread of the pandemic driving higher demand in the first quarter of 2020 for Abbott’s CentriMag™ circulatory support systems which are used in acute hospital care. Excluding the effect of foreign exchange, the 2.0 percent decline in Vascular sales reflects price reductions on drug-eluting stents across various geographies and lower sales in China due to a new national tender program instituted in the fourth quarter of 2020, partially offset by the improvement in procedure volume trends in various countries.
The gross profit margin percentage was 53.0 percent for the first quarter of 2021 compared to 50.3 percent for the first quarter of 2020. The increase primarily reflects higher sales volume in various businesses, higher utilization at various manufacturing sites, and a decrease in intangible amortization expense in 2021.
Research and development expenses increased $76 million, or 13.3 percent, in the first quarter of 2021. The 2021 increase in R&D expense was primarily driven by higher spending on various projects to advance products in development. For the three months ended March 31, 2021, research and development expenditures totaled $317 million for the Medical Devices segment, $168 million for the Diagnostic Products segment, $45 million for the Nutritional Products segment and $50 million for the Established Pharmaceutical Products segment.
Selling, general and administrative (SG&A) expenses for the first quarter of 2021 increased $235 million, or 9.2 percent, due primarily to charges related to certain litigation and higher selling and marketing spending to drive growth across various businesses.