#141st Annual J.P. Morgan Healthcare Conference January 10, 2023 Tony J. Hunt President and CEO R REPLIGEN#2Safe Harbor / Non-GAAP financial measures This presentation contains forward-looking statements within the meaning of the federal securities laws. Statements in this presentation which are not strictly historical statements including, without limitation, express or implied statements or guidance regarding Repligen's estimated financial results for full year 2022, future financial performance and other statements identified by words like "estimated," "anticipated," "guidance," or "goal," and similar expressions are forward-looking statements. These statements are subject to risks and uncertainties which may cause our plans to change or actual results to differ materially from those anticipated. In particular, unforeseen events outside of our control may adversely impact future results. Additional information concerning these factors is discussed in our reports filed with the Securities and Exchange Commission including recent Form 8-Ks, our most recent Annual Report on Form 10K and our most recent Quarterly Reports on Form 100, all of which are available on our website. The forward-looking statements in this presentation reflect management's current views and may become obsolete as a result of new information, future events or otherwise. We may not update such forward looking statements to reflect a change of events or circumstances that occur after the date hereof, except as required by law. The industry and market data contained in this presentation are based on management's own estimates, independent publications, government publications, reports by market research firms or other published independent sources, and, in each case, are believed by management to be reasonable estimates. Although we believe these sources are reliable, we have not independently verified the information. This presentation discloses certain financial measures not prepared in accordance with generally accepted accounting principles, or GAAP. Repligen strongly encourages investors to review our consolidated financial statements and publicly filed reports in their entirety and cautions investors that the non- GAAP measures used herein may differ from similar measures used by other companies, even when similar terms are used to identify such measures. R REPLIGEN 2#3Repligen Overview Strong Revenue Growth through Innovation Leadership R REPLIGEN#4We are the innovation leader in bioprocessing Enabling efficient, single-use, high productivity biological drug manufacturing History of exceptional growth and expansion: $800M 2022e Revenue +19%-20% vs. 2021 Differentiated technologies R REPLIGEN +41% 5-year CAGR +26% 5-year avg. base revenue growth Innovation, acquisitions, market strength ~30% 2022e Revenue from new markets (COVID & GT) ~70% mAbs/other Diversified customer base, all biological drug modalities 10 Disruptive technology launches ~26% of our revenue in 2022 65% Clinical 35% Commercial (excl. COVID) 300 person commercial team Late-stage clinical pipeline will drive growth 2022e figures reflects guidance as of our Q3 earnings call Nov. 1, 2022. "Base" excludes COVID-related & inorganic M&A revenue, includes FX impact. 4#5Strong revenue growth driven by innovation and portfolio expansion Analytics ~$57M 7% Chroma $36M 26% 2017 $141M Revenue R REPLIGEN Filtration $49M 35% Proteins $54M 38% 2017-2022 34% 5-year avg. annual organic growth Chroma ~$125M 16% Proteins ~$110M 14% 2022e $800M Revenue Filtration ~$505M 63% Long life-cycle, highly differentiated systems and consumable products 2022e total revenue reflects guidance midpoint as of our Q3 earnings call Nov. 1, 2022. 2022e franchise-level revenue and percent of total reflect franchise-level growth estimates as of our Q3 earnings call Nov. 1, 2022. 5#62022e revenue splits (directional) Consumables, biopharma development and mAb applications were the largest contributors CONSUMABLES/EQUIPMENT % of Total Revenue 25% R REPLIGEN 75% Equipment Consumables BIOPHARMA/CDMO/INTEGRATORS % of Total Revenue 17% 4% 29% 49% Biopharma Developers CDMOS Integrators Other 2022e total revenue reflects guidance midpoint as of our Q3 earnings call Nov. 1, 2022. BIOLOGIC TYPE 17% (COVID) 13% (C&GT) $138M TOTAL: $800M $105M 70% (mAbs) $557M 6#7Market Landscape & Addressable Market Healthy End Markets and Expanding TAM R REPLIGEN#8mAbs, Gene Therapy and mRNA fueling our growth Monoclonal Antibodies Cell & Gene Therapy R REPLIGEN ~$150B Market 2021 Growing at >10% annually >$5B Market 2021 Growing at >25% annually >140 U.S. FDA Approvals incl. 26 Biosimilars 14 U.S. FDA Approvals incl. 9 Cell, 5 GT >800 Phase I-III >1,500 Active clinical trials >500 Phase I-III >1,100 Active clinical trials New approvals and growing biosimilars pipeline Emerging opportunities beyond COVID Data sources: $s Company filings/guidance; Approvals: U.S. FDA website; Industry articles incl. www.genengnews.com/a-lists/top-11-best-selling-covid-19-vaccines-and-drugs-of-h1-2021/mAb approvals: Antibody therapeutics approved or in regulatory review in the EU or US - The Antibody Society/; PHrMA report https://phrma.org/-/media/Project/PhRMA/PhRMA-Org/PhRMA-Org/PDF/A-C/MID-cell-and- gene-therapy-2020.pdf; Repligen internal mAbs tracker; Market research reports (Research and Markets, Allied Market Research, Brandessence Research, Fortune Business Highlights, Qualiket Research.. Candidates C&GT: 2)Cell & Gene Therapy reports: American Society of Gene + Cell Therapy: Q2 2022 Cell, Gene & RNA Therapy Trials C&GT: BioCentury 8#9Biosimilar mAbs market opportunities expanding Global Biosimilar Market Outlook¹ $20B Approved biosimilars² $30B 2022 2025 97 programs in development² 8 years after 1st biosimilar approval 15 $60B 36 2030 21 launched 23 mAbs EU US ¹ McKinsey & Co, An inflection point for biosimilars, June 2021. ² Amgen Biosimilars 2022 Trend Report. 1st approvals: 2006 EU, 2015 US R REPLIGEN "Top 6" mAbs with launched biosimilars US FDA approved biosimilars 81 JH HUMIRA adalimumab LUCENTIS RANIBIZUMAB INJECTION X AVASTIN bevacizumab MALINJECTION FOR Remicade INFLIXIMAB Herceptin trastuzumab 21 mg/mL INJECTION FOR INTRAVENOUS USE Rituxan Rituximab Total Sales 2021 Sales $20.7B $3.6B $3.4B $3.2B $2.9B $2.8B $36.6B ¹2 additional approvals pending for 1H-23 2 1 3 4 LO 5 3 24 approved 14 launched Looking Ahead: 8 Humira biosimilars go commercial in 2023 4 additional blockbuster mAbs² with $29B in 2021 sales come off patent over the next 5 years Opdivo (BMS), Perjeta® (Roche), Stelara® (Janssen), Eylea® (Regeneron) 9#10mRNA is a major new modality and market driver Leading COVID vaccine developers advancing non-COVID mRNA programs moderna +30 programs 20 non-COVID 2Pfizer $470M in mRNA vax, 12.13.22 Moderna, Merck mRNA cancer vaccine slashes melanoma recurrence in Keytruda combo trial MERCK moderna R REPLIGEN BIONTECH 15 programs 15 non-COVID Growing number of large pharma companies with deep pipelines in mRNA CUREVAC 06.26.22 BioNTech/Roche mRNA Therapy for Pancreatic Cancer Inspires Early Optimism BIONTECH COVID program counts are from company presentations and websites December 2022 the RNA people® 7 programs 4 non-COVID 04.20.22 Sanofi breaks ground on first-of-its-kind Evolutive Vaccine Facility in Asia sanofi 10