A BioCentury report on Sydnexis’ complete response letter (CRL) has reignited criticism about the FDA’s transparency and shifting review standards, and hundreds of biotech leaders have sent a letter urging agency stability. Sydnexis’ CRL was cited as an example of opaque agency decision-making that could have been clearer through public advisory committee discussion, according to industry sources. Separately, a broad coalition of biotech CEOs warned FDA director Marty Makary that regulatory volatility threatens US innovation and called for predictable review pathways and clearer communications. Together the two developments sharpen industry concerns around review consistency and the need for more transparent dialogues between regulators and sponsors.