Lexicon submitted additional clinical data to the FDA from three ongoing investigator-initiated studies of sotagliflozin to address the agency’s December 2024 complete response letter for Zynquista, which cited increased diabetic ketoacidosis risk in type 1 diabetes. The company has a Type D meeting in process and expects FDA feedback by the end of September on whether the package supports a reasonable path to resubmission for use as an adjunct to insulin in adults with T1D.
The filing leans on external programs at Steno Diabetes Center (STENO1), Joslin Diabetes Center (SUGARNSALT), and the University of Dundee (SOPHIST). While the trials are ongoing and not designed as registrational studies, they collectively explore cardio-renal outcomes and safety management in T1D populations using sotagliflozin. The move follows multiple cycles of regulatory friction around SGLT-based adjunct therapy in T1D, where efficacy signals have been consistent but DKA has remained the gating issue. Lexicon has signaled it is no longer funding company-run T1D trials; this submission is therefore a capital-light bid to reopen the label discussion using third-party data and real-world practice patterns rather than fresh sponsor-led RCTs.
Strategically, this is a test of the FDA’s willingness to accept investigator-initiated and pragmatic evidence to rebalance benefit-risk when a safety signal is well-characterized and potentially mitigable. The likely pitch is not that DKA risk disappears, but that it can be managed through structured education, ketone monitoring, and patient selection protocols while delivering glycemic and cardio-renal advantages. Sotagliflozin’s broader clinical experience across diabetes, heart failure, and CKD—spanning roughly 20,000 patients—gives Lexicon more context on class effects, but the T1D use case will rise or fall on contemporary DKA mitigation.
For sites and clinicians, a positive signal from the FDA would foreshadow operational requirements: standardized risk management plans, reliable access to blood ketone testing, documentation of sick-day rules, and tighter coordination with pump and CGM workflows. If approval proceeds with a REMS, training and certification burdens will land on endocrinology practices and integrated delivery networks, and vendors offering connected ketone devices and remote monitoring could become embedded in care pathways. For sponsors and CROs, the submission probes the boundary of how much weight the FDA will place on high-quality IIT data to resolve a CRL—useful intelligence for portfolio teams considering adjunct indications that hinge on risk mitigation rather than new efficacy.
Regulators are balancing patient advocacy and unmet need against a safety profile that previously led to global retrenchment of SGLT use in T1D. If the FDA entertains a resubmission, expect narrow labeling, clear exclusion criteria, and stringent monitoring obligations. Payers would likely layer on prior authorization tied to adherence with mitigation protocols, reinforcing workflow complexity at the site level.
The near-term marker is the end-of-September readout from the Type D interaction. What matters is whether FDA requires a new, prospectively powered U.S. study specifically focused on DKA incidence under modern ketone-monitoring standards, or whether a combined package of IIT data, risk management commitments, and postmarketing surveillance would suffice. Lexicon’s stated stance against new sponsor-led T1D trials means a requirement for fresh randomized data could stall the program. Conversely, if the agency signals openness to a tightly controlled label backed by pragmatic evidence, Zynquista could re-enter the conversation—and set a precedent for using investigator-led data to navigate safety-driven CRLs in niche adjunct indications.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
