Silence Therapeutics advanced its small interfering RNA (siRNA) program for polycythemia vera (PV), reporting positive Phase 2 results for divesiran in the SANRECO trial (NCT05499013). The company said divesiran met the primary endpoint with an 88% response rate compared with 19% in placebo-controlled groups. PV is driven by excessive red blood cell production and is managed largely through repeated phlebotomies to keep hematocrit below target levels and reduce thrombotic risk. Silence reported divesiran enabled more consistent hematocrit control and substantially reduced the need for phlebotomy, with infrequent dosing in some patients. Mechanistically, divesiran silences TMPRSS6, a regulator of iron balance and red blood cell production. Silence’s results position the asset as a potential non-phlebotomy approach for a rare hematologic cancer where durable hematocrit control is closely linked to morbidity and mortality risk.