Alnylam Sues Cipla Over Generic AMVUTTRA (Vutrisiran) Injection.

Alnylam Pharmaceuticals, Inc. filed Alnylam Pharmaceuticals, Inc. v. Cipla USA Inc. et al., No. 1:26-cv-01166 (D. Del.), on September 16, 2026. Defendants are Cipla USA Inc. and Cipla Ltd. (together, Cipla). The suit follows Cipla's August 3, 2026 Paragraph IV notice letter for ANDA No. 221202 seeking approval of vutrisiran sodium injection, 25 mg/0.5 mL, as a generic version of AMVUTTRA.

Patents and accused products

The complaint lists five patents in the case: U.S. Patents 10,612,024; 10,208,307; 10,683,501; 11,286,486; and 12,049,628. The accused product is Cipla's ANDA Product under ANDA No. 221202 - generic AMVUTTRA (vutrisiran) injection, 25 mg/0.5 mL. Alnylam pleads Hatch-Waxman infringement under 35 U.S.C. § 271(e)(2) from the ANDA filing, plus inducement and contributory infringement tied to proposed labeling, and seeks declaratory judgments of infringement for each patent.

Example claims pleaded in the counts include claim 17 of the '024 patent, claim 22 of the '307 patent, claim 21 of the '501 patent, claim 21 of the '486 patent, and claim 1 of the '628 patent. The complaint further states that Cipla's notice letter did not contest infringement of claims 1-30 of the '024 patent; claims 1-13, 17-27, 30-35, and 38-75 of the '307 patent; and claims 1-33 of the '628 patent, other than on invalidity grounds. The '501 and '486 counts do not recite comparable non-contest ranges.

What the patents cover

U.S. Patent 10,612,024 (Modified double-stranded RNA agents) covers double-stranded RNAi agents designed to silence a target gene, with specified chemically modified sense and antisense strands. Asserted claims: one or more claims, including for example claim 17; notice letter did not contest infringement of claims 1-30 except on invalidity. Claim 17 covers a claim-1 dsRNA agent whose sense strand carries 2'-fluoro modifications at positions 7 and 9-11, whose antisense strand carries 2'-fluoro modifications at positions 2, 6, 14, and 16, and whose strands together include six phosphorothioate internucleotide linkages.

U.S. Patent 10,208,307 (Transthyretin (TTR) iRNA compositions and methods of use thereof for treating or preventing TTR-associated diseases) covers double-stranded RNAi agents that target the TTR gene, including agents with defined sense and antisense sequences and GalNAc ligand conjugation. Asserted claims: one or more claims, including for example claim 22; notice letter did not contest infringement of claims 1-13, 17-27, 30-35, and 38-75 except on invalidity. Claim 22 covers a dsRNAi agent with the specified sense strand ending in L96 (GalNAc) and the matching antisense strand, using defined 2'-O-methyl, 2'-fluoro, and phosphorothioate chemistry.

U.S. Patent 10,683,501 covers methods of prophylactically treating a human subject at risk for a TTR-associated disease by administering a prophylactically effective amount of a defined TTR-targeting dsRNAi agent. Asserted claims: one or more claims, including for example claim 21. Claim 21 covers that prophylactic method using the GalNAc-conjugated sense/antisense pair matching the vutrisiran sequence chemistry pleaded in the complaint.

U.S. Patent 11,286,486 covers methods of treating a subject suffering from a TTR-associated disease by administering a therapeutically effective amount of a defined TTR-targeting dsRNAi agent. Asserted claims: one or more claims, including for example claim 21. Claim 21 covers that treatment method using the same GalNAc-conjugated sense/antisense pair.

U.S. Patent 12,049,628 covers a salt of a double-stranded RNAi agent for inhibiting TTR expression built from the same core sense and antisense sequences with defined 2'-O-methyl, 2'-fluoro, and phosphorothioate chemistry. Asserted claims: one or more claims, including for example claim 1; notice letter did not contest infringement of claims 1-33 except on invalidity. Claim 1 covers that TTR-inhibiting RNAi salt with the recited sense and antisense sequences.

What the lawsuit is about

Alnylam ties Cipla's ANDA Product to AMVUTTRA's vutrisiran RNAi sequence and chemistry, as described in Cipla's notice letter, and alleges that commercial launch and label-directed use will infringe composition and method claims across the five patents. Alnylam asks to delay FDA approval until patent expiry and for injunctive relief against manufacture, use, sale, and importation of the ANDA product.

What it means

This is a Delaware Hatch-Waxman case on generic AMVUTTRA, centered on chemically modified TTR-silencing RNAi agents and related prophylactic and treatment methods. Expect validity fights on the composition and method patents, claim-scope disputes over sequence, modification pattern, and GalNAc conjugation, and coordination questions with any other Alnylam-Cipla Delaware captions.

What to watch next

Watch Cipla's answer and any early invalidity or noninfringement contentions, especially where the notice letter already narrowed the infringement fight to validity. Also watch the 30-month stay clock tied to the August 3, 2026 Paragraph IV notice and whether related Alnylam-Cipla Delaware matters are coordinated.