It is interesting that this myth about the lack of independent studies continues to get traction, since independent academic researchers are always doing research on biotech products and evaluating published studies through review articles.
For instance, from 2001 to 2010, more than 50 studies were conducted in Europe alone, funded by the European Commission (at a cost of >200 million euros) and performed by more than 400 independent research groups. These studies are summarized in “A Decade of EU-Funded GMO Research.” This report concluded that “biotechnology, and in particular GMOs, are not per se more risky than, e.g., conventional plant breeding technologies.”
Additionally, as my colleague John Vicini answered here:
“A 2012 literature review by Snell et al. provides a good summary of feeding studies with diets containing large amounts of GMO-derived ingredients (C. Snell et al., “Assessment of the health impact of GM plant diets in long-term and multigenerational animal feeding trials: a literature review,” Food Chem Toxicol. 50 (2012): 1134–48). This paper also includes a section specifically devoted to long-term studies and provides funding information for each of these studies. Independent scientists performed all of these studies, and most of the studies were independently funded as well. However, only 50% of the studies list the funding sources, so we can only verify that those studies were independently funded.”
Also, there are hundreds of independently funded studies that can be found at the BioFortified website. These are just a few examples of the independent studies that have been performed and can be accessed by anyone. You may also find that a blog post entitled “About Those Industry Funded GMO Studies…” addresses your question pretty well.