Schall, Brown & Schwartz LLP announced a securities fraud investigation into Alnylam Pharmaceuticals on Aug. 3, joining Kirby McInerney LLP and Bronstein, Gewirtz & Grossman LLC. The probe centers on whether the company misled investors about its TTR product launch in the ATTR-CM market. No lawsuit has been filed.
Alnylam Pharmaceuticals faces a securities fraud investigation after cutting 2026 TTR revenue guidance by $200 million, sending shares down 28 percent.
"Our practice centers on restoring investor capital and ensuring corporate accountability, which serves to uphold the essential integrity of the marketplace," Peretz Bronstein, founding partner at Bronstein, Gewirtz & Grossman LLC, said.
Alnylam reported second-quarter 2026 results on July 30, saying it "lowered our TTR product sales guidance for full-year 2026 to reflect learnings from the initial phase of our launch in the evolving ATTR-CM market, in particular the normalization of growth in second line volume after satisfying pent-up demand from patients waiting for a new therapy." Shares fell $81.14 to close at $205.48 that day, with an intraday drop of as much as $81.25, or 28.35 percent.
The investigations focus on whether Alnylam or its senior management violated federal securities laws by failing to disclose information pertinent to investors about the TTR launch trajectory. The company's TTR franchise, anchored by its RNAi therapeutic patisiran, is a core growth driver as Alnylam expands beyond hereditary ATTR amyloidosis into the broader ATTR-CM indication, where it competes with Pfizer's tafamidis franchise and Ionis Pharmaceuticals' emerging candidates.
The guidance cut reflects a slower-than-expected ramp in second-line therapy volume after an initial surge from patients who had been waiting for a new treatment option. Kirby McInerney LLP opened its investigation on July 31, and Bronstein, Gewirtz & Grossman followed on Aug. 2, with SBS Law announcing its probe on Aug. 3. Each firm is examining whether the company issued false or misleading statements about the pace of its launch in the ATTR-CM market.
The ATTR-CM market represents a significant expansion opportunity for Alnylam, which built its commercial base in the smaller hereditary ATTR amyloidosis patient population. The company's guidance revision implies a more gradual adoption curve for its therapy in the broader cardiomyopathy indication, a dynamic that could affect revenue projections for the full year and beyond. Alnylam's stock now trades well below its pre-announcement levels, and the multiple investigations compound the negative sentiment around the name.
The ATTR-CM treatment landscape has become increasingly competitive, with multiple therapeutic approaches vying for market share. Pfizer's tafamidis has established a strong position in the first-line setting, while Alnylam's RNAi approach targets the underlying production of transthyretin protein. The company's guidance revision suggests that second-line adoption is progressing more slowly than management had projected, raising questions about the durability of the initial launch momentum.
The legal scrutiny adds uncertainty to a stock already down sharply from pre-announcement levels. Investors holding ALNY shares should watch for a potential class action filing and any further disclosures from the company about TTR launch dynamics in its next earnings call.
This article is for informational purposes only and does not constitute investment advice.
