Alnylam Pharmaceuticals Reports Fourth Quarter and Full Year 2018 Financial Results and Highlights Recent Period Activity Achieved Fourth Quarter 2018 ONPATTRO Global Net Product Revenues of $12.1 Million, with Over 200

Pharmaceuticals Reports Fourth Quarter and Full Year 2018 Financial

Results and Highlights Recent Period Activity

Achieved Fourth Quarter 2018 ONPATTRO Global Net Product Revenues of

$12.1 Million, with Over 200 Patients on Commercial Product in U.S. and

EU as of Year-End 2018 -

Obtained Regulatory Alignment on APOLLO-B Phase 3 Study of Patisiran in

ATTR Amyloidosis with Cardiomyopathy and Initiated HELIOS-A Phase 3

Study to Advance Vutrisiran to Market, Supporting Plan for Sustained and

Continuous Growth of ATTR Franchise -

Advanced Additional Phase 3 Programs, Including Givosiran, with Rolling

Submission of New Drug Application (NDA) Initiated and Topline ENVISION

Phase 3 Results Expected in March, and Lumasiran, with ILLUMINATE-A

Phase 3 Study Initiated -

Maintained Strong Balance Sheet with $1.13 Billion in Cash as of

Provides 2019 Non-GAAP R&D and SG&A Expense Guidance -

CAMBRIDGE, Mass.--(BUSINESS WIRE)--February 7, 2019--Alnylam

Pharmaceuticals, Inc. (Nasdaq: ALNY), the leading RNAi therapeutics

company, today reported its consolidated financial results for the

fourth quarter and full year ended December 31, 2018 and reviewed recent

commercial and R&D highlights.

"In 2018, we saw the approval and launch of ONPATTRO, the world's first

RNAi therapeutic, heralding the arrival of a whole new class of

medicines. With our planned APOLLO-B Phase 3 study to support potential

expansion of ONPATTRO to ATTR amyloidosis patients with cardiomyopathy

and advancement of subcutaneously administered vutrisiran in the

HELIOS-A Phase 3 study, we are committing further efforts to help ATTR

amyloidosis patients and to support our plans for the sustained and

continued growth in our ATTR amyloidosis franchise for years to come,"

said John Maraganore, Ph.D., Chief Executive Officer of Alnylam. "While

executing on our efforts to bring ONPATTRO to patients around the world,

we also made great strides advancing our pipeline of investigational

RNAi therapeutics. In 2019, we intend to execute on six Phase 3 programs

- of which two are being advanced together with partners - with Phase 3

data expected from three of these programs, and expect two NDA

submissions, assuming positive results. In the meanwhile, we'll continue

to benefit from a sustainable RNAi research engine that we expect will

fuel future innovation and deliver important medicines for patients."

"We are pleased with our commercial progress to date, as we strive to

make ONPATTRO available to patients around the world. Specifically, we

are encouraged by our fourth quarter 2018 results, with over 200

patients receiving treatment with commercial ONPATTRO in the U.S. and EU

since launch, reflecting what we believe to be strong patient and

physician demand and excellent performance by our customer-facing field

teams," said Barry Greene, President of Alnylam. "In 2019, we're focused

on continued execution of our ONPATTRO launch in the U.S. and EU, while

expanding our global commercial presence in Asia and Latin America.

Longer term, we're excited by the opportunity for positive impact for

patients, patient families and caregivers, and meaningful growth

potential for our ATTR amyloidosis franchise."

Fourth Quarter 2018 and Recent Significant Corporate Highlights

Commercial Performance at Year-End 2018

Achieved global net product revenues for the fourth quarter of 2018 of

$12.1 million for ONPATTRO, and $12.5 million for the full year ended

Attained over 200 patients in the U.S. and EU on commercial ONPATTRO

Including patients on commercial drug and patients in clinical

studies and in the Company's global Expanded Access Program (EAP),

approximately 550 total patients worldwide were being treated with

Received a total of 250 Start Forms in the U.S., with approximately 50

percent from patients not previously treated in the ONPATTRO EAP.

Start Forms came from a diverse range of prescribing physician

specialties, including 44 percent from neurologists, 35 percent

from cardiologists, and 21 percent from other specialties.

For Start Forms received, 62 percent of patients were covered by

Medicare, 32 percent were covered by commercial insurers, and 6

percent were covered by other government insurers.

Continued significant progress with value-based agreements (VBAs) with

commercial payers in the U.S. and with market access efforts in the EU.

Since launch, Alnylam has completed definitive VBAs with Harvard

Pilgrim Healthcare, Humana, and another top five U.S. payer.

Additional VBAs are under negotiation with over 15 other

commercial payers with the potential to cover over 90 percent of

commercial lives in the U.S.

The Company announces today that it has advanced pricing &

reimbursement procedures with authorities in 15 EU countries -

representing the vast majority of the hATTR amyloidosis

opportunity in Europe - with positive feedback from several EU

payers. Recent examples include positive technology assessment

reports from authorities in Germany and Sweden, the special

innovation designation of ONPATTRO by the Italian authorities, and

favorable alignment with authorities in The Netherlands, among

Advanced patisiran (the non-branded name for ONPATTRO), an

intravenously administered investigational RNAi therapeutic in

development for the treatment of ATTR amyloidosis.

Continued global efforts to bring ONPATTRO to patients with filing

of a New Drug Submission (NDS) in Canada and a Marketing

Authorisation Application (MAA) in Switzerland, which has now been

Obtained alignment with the U.S. Food and Drug Administration

(FDA) on the design of APOLLO-B, a randomized, double-blind,

placebo-controlled Phase 3 study of patisiran in hereditary and

wild-type ATTR amyloidosis patients with cardiomyopathy, with the

goal of starting the trial in mid-2019.

Advanced vutrisiran (ALN-TTRsc02), a subcutaneously administered

investigational RNAi therapeutic in development for the treatment of

Initiated HELIOS-A Phase 3 study in hereditary ATTR amyloidosis

with polyneuropathy.

Announced plans to initiate an additional Phase 3 study, HELIOS-B,

of vutrisiran in hereditary and wild-type ATTR amyloidosis with

cardiomyopathy in late 2019.

Advanced givosiran, an investigational RNAi therapeutic in development

for the treatment of acute hepatic porphyria (AHP).