Apellis Pharmaceuticals, Inc., a commercial-stage biopharmaceutical company, focuses on the discovery, development, and commercialization of therapeutic compounds through the inhibition of the complement system for autoimmune and inflammatory diseases. It offers EMPAVELI for the treatment of paroxysmal nocturnal hemoglobinuria, C3 glomerulopathy and immune complex membranoproliferative glomerulonephritis, and hematopoietic stem cell transplantation-associated thrombotic microangiopathy; and SYFOVRE for treating geographic atrophy secondary to age-related macular degeneration and geographic atrophy (GA). The company also develops APL-3007, a small interfering RNA, or siRNA, which is in a Phase 1 clinical trial, as well as an oral complement inhibitor that is in preclinical development. It has a collaboration and license agreement with Swedish Orphan Biovitrum AB (publ) for development and commercialization of pegcetacoplan; and a collaboration with Beam Therapeutics Inc. focused on the use of Beam's base editing technology to discover new treatments for complement-driven diseases. The company was incorporated in 2009 and is based in Waltham, Massachusetts.

Upstream Bio, Inc., a clinical-stage biotechnology company, develops treatments for inflammatory diseases that focuses on severe respiratory disorders. It develops verekitug, a monoclonal antibody that targets and inhibits the thymic stromal lymphopoietin receptor. The company also develops therapies to treat severe asthma, chronic rhinosinusitis with nasal polyps, and chronic obstructive pulmonary disease. Upstream Bio, Inc. was incorporated in 2021 and is based in Waltham, Massachusetts.

PureTech Health plc, engages in the development and commercialization of biotechnology and pharmaceutical solutions in the United States. The company is developing LYT-100, which is under Phase 2 stage, to treat idiopathic pulmonary fibrosis (IPF); and LYT-200, a IgG4 monoclonal antibody, currently under Phase 1/2 stage, targeting galectin-9 for treating solid tumors and hematological malignancies. It also develops SPT-300, an oral drug of allopregnanolone for the treatment of anxious depression; SPT-320, a novel prodrug of agomelatine for the treatment of generalized anxiety disorder; and SPT-348, a prodrug of a non-hallucinogenic neuroplastogen for the treatment of mood and other neuropsychiatric disorders. In addition, the company is developing hydrogels to enable the oral administration of peptide therapeutics in preclinical development. The company was incorporated in 2015 and is headquartered in Boston, Massachusetts.

Astria Therapeutics, Inc., a biopharmaceutical company, focuses on the discovery, development, and commercialization of therapeutics for allergic and immunological diseases in the United States. Its lead product candidate is STAR-0215, a monoclonal antibody inhibitor of plasma kallikrein, which is in Phase 1b/2 clinical trials for the treatment of hereditary angioedema. The company is also developing STAR-0310, a monoclonal antibody OX40 antagonist that is in preclinical development for the treatment of atopic dermatitis, an immune disorder associated with loss of skin barrier function and itching. The company was formerly known as Catabasis Pharmaceuticals, Inc. and changed its name to Astria Therapeutics, Inc. in September 2021. Astria Therapeutics, Inc. was incorporated in 2008 and is headquartered in Boston, Massachusetts.

Invivyd, Inc., a commercial-stage biopharmaceutical company, focuses on the discovery, development, and commercialization of antibody-based solutions for infectious diseases in the United States. The company developed INVYMAB, a platform that combines viral surveillance and predictive modeling with advanced antibody engineering. Its pipeline includes PEMGRADA (pemivibart) injection, a half-life extended investigational monoclonal antibody (mAb) for the prevention of COVID-19 in adults and adolescents; VYD2311, an mAb candidate which is in preclinical studies for the prevention or treatment for COVID-19; and adintrvimab, that is in phase 3 clinical trials for the prevention or treatment of COVID-19. The company also has discovery stage candidates for the prevention of seasonal influenza and COVID-19. It has a collaboration agreement with Adimab, LLC for the discovery and optimization of proprietary antibodies; and the Scripps Research Institute to perform research activities to identify vaccine candidates for the prevention, diagnosis or treatment of influenza or beta coronaviruses. The company was formerly known as Adagio Therapeutics, Inc. and changed its name to Invivyd, Inc. in September 2022. Invivyd, Inc. was incorporated in 2020 and is headquartered in Waltham, Massachusetts.

Q32 Bio Inc., a clinical-stage biotechnology company, develops biologic therapeutics to restore healthy immune balance in patients with autoimmune and inflammatory diseases driven by pathological immune dysfunction in the United States. Its lead product candidate is ADX-097, a humanized anti-C3d monoclonal antibody fusion protein to restore complement regulation, which has completed Phase I clinical trial for the treatment of renal and other complement-mediated diseases of high unmet need, including lupus nephritis, immunoglobulin A nephropathy, complement component 3 glomerulopathy, and anti-neutrophil cytoplasmic antibody-associated vasculitis. The company is also developing Bempikibart (ADX-914), a fully human anti–interleukin-7 receptor alpha antagonist monoclonal antibody designed to re-regulate adaptive immune function by blocking signaling mediated by interleukin-7 and thymic stromal lymphopoietin that is Phase II clinical trial for the treatment of atopic dermatitis and alopecia areata. Q32 Bio Inc. was formerly known as AdMIRx Inc. and changed its name to Q32 Bio Inc. in April 2020. The company was founded in 2017 and is based in Waltham, Massachusetts.

Abpro Holdings, Inc., a biotechnology company, engages in developing antibody therapeutics for patients with immuno-oncology, ophthalmology, and autoimmunity issues. Its platform DiversImmune addresses a bottleneck in the antibody therapeutics industry. Its lead product candidates include ABP-100 for the treatment of breast, gastric, and colorectal cancers; and ABP-201 for the treatment of vascular diseases of the eye. The company has a strategic partnership with Abpro Bio Co. Ltd and NJCTTQ. The company was formerly known as Abpro Corporation and changed its name to Abpro Holdings, Inc. in November 2024. Abpro Holdings, Inc. was incorporated in 2004 and is headquartered in Woburn, Massachusetts.

Aptorum Group Limited, through its subsidiaries, operates as a clinical stage biopharmaceutical company that engages in the discovery, development, and commercialization of therapeutic products for the treatment of oncology and infectious diseases. The company operates in the Therapeutics and Non-Therapeutics segments. Its pipeline products include SACT- 1 for neuroblastoma and other cancer types; SACT-COV19 for the treatment of coronavirus disease; ALS-4 to treat bacterial infections caused by staphylococcus aureus, including MRSA; ALS-1 to treat viral infections caused by influenza virus A; and ALS-2/3 for the treatment of gram+ve bacterial infections. The company is also developing RPIDD, a pathogen molecular diagnostic; NativusWell DOI (NLS-2), a dietary supplement; NLS-1 for the treatment of endometriosis; DLS-1+2 to treat NSCLC with mutation; DLS-3, an autoimmune small molecule; and CLS-1 for the treatment of obesity. Its pipeline products enable the discovery of new therapeutics assets, such as systematic screening of existing approved drug molecules, and microbiome-based research platforms for treatment of metabolic diseases. The company also focuses on therapeutic and diagnostic projects in neurology, gastroenterology, metabolic disorders, and other disease areas. In addition, it is involved in the operation of medical clinics. The company was formerly known as APTUS Holdings Limited and changed its name to Aptorum Group Limited in October 2017. Aptorum Group Limited was incorporated in 2010 and is headquartered in London, the United Kingdom.