Tenax Therapeutics’ TNX-103 failed to hit the primary efficacy goal in a Phase 3 trial for heart failure associated with pulmonary hypertension (PH-HFpEF), triggering an early investor retreat. In the LEVEL study, the oral formulation of levosimendan improved six-minute walk distance by 14 meters versus 10.4 meters with placebo at 12 weeks, but the between-group difference was not statistically significant. Tenax also reported no significant separation on symptom burden at the 12-week timepoint. Leerink Partners characterized the results as “very disappointing,” citing a “surprising” placebo response as a key contributor to the late-stage stumble. Despite the miss, the company pointed to prespecified subgroup signals—particularly among older patients and those with worse baseline exercise capacity. Tenax CEO Chris Giordano said the full LEVEL dataset will “guide us toward approval,” arguing that the analyses could sharpen the target population for future development. The sharp selloff underscores the commercial stakes in heart failure—where modest functional gains and clear statistical significance often determine whether an asset can progress to registrational discussions.