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Coming out of the lull of August, the biopharma industry witnessed four billion-dollar acquisition deals in September 2025. Licensing deals involved antibody-drug conjugates, small molecules, and RNAs, with Novartis taking the cake for the highest number of collaborations. New players also forged relationships to develop new therapies.
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Top biotech M&As of September 2025
The month of September was a big one for mergers and acquisitions (M&As) in the biotech industry. There were four billion-dollar acquisitions that were the most notable. The top buyout was Danish antibody therapeutics company Genmab’s $8 billion acquisition of Netherlands-based Merus. The latter, being a bispecific antibody developer itself, adds to Genmab’s antibody pipeline. This includes Merus’ lead asset petosemtamab for head and neck cancers, which has bagged two breakthrough therapy designations from the U.S. Food and Drug Administration (FDA).
Pfizer’s proposed buyout of American obesity treatments company Metsera was the second highest M&A announced last month. It will pay $7.3 billion to gain control of Metsera’s oral and injectable GLP-1 agonists, which are all in clinical and investigational new drug (IND)-enabling stages. Among the most advanced is the injectable GLP-1 MET-097i.
Swiss pharma giant Roche took over California-based metabolic disease therapeutics company 89bio for $7.3 billion. Roche will nab 89bio’s metabolic dysfunction-associated steatohepatitis (MASH) candidate pegozafermin, which is an engineered FGF21 analog. Roche has been immersed in the metabolic disease space for a while, as it has ongoing partnerships with other biotechs like American biotechs Alnylam and Carmot Therapeutics, and Danish company Zealand.
Meanwhile, fellow Swiss multinational biopharma Novartis purchased New York-based Tourmaline Bio for $1.4 billion. Its prized possession is the clinical monoclonal antibody candidate pacibekitug for treating cardiovascular inflammation in atherosclerotic cardiovascular disease – caused by plaque buildup in the walls of the arteries – and abdominal aortic aneurysm, which is characterized by swelling in the arteries. The drug is also being tested in the clinic for the autoimmune disease thyroid eye disease. This comes after Novartis’ collaborations with biotechs such as Swedish biopharma BioArctic and Massachusetts-based Matchpoint Therapeutics in the past couple of months.
Finally, Cambridge, U.S.-headquartered multinational biotech Biogen has announced plans to buy Massachusetts-based Alcyone Therapeutics for $85 million upfront. Biogen will now take the reins of Alcyone’s pipeline of gene therapies and small molecules, the leading one being gene therapy CLN-301 for Batten disease, a fatal neurological condition. It will also obtain Alcyone’s implantable device for the delivery of antisense oligonucleotides to the spinal cord to treat spinal muscular atrophy, a genetic disease characterized by progressive muscle weakness.
Biotech deals by approach in September 2025
Antibody-drug conjugates draw interest from biopharmas
In September 2025, Indian pharmaceutical Glenmark and Chinese biotech company Hengrui Pharma have signed a deal over the latter’s HER2 antibody-drug conjugate. Glenmark can assume control over the drug’s development in countries excluding China, Hong Kong, Macao, Taiwan, the U.S., Canada, Europe, Japan, Russia, Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Tajikistan, Turkmenistan and Uzbekistan. Hengrui will pocket $18 million upfront and $1.093 billion in regulatory and commercial milestones. The drug that is being licensed is called trastuzumab rezetecan for HER2-positive solid tumors. Hengrui has ramped up its involvement with other biopharmas of late, as it forged another deal in September as well as one with GSK in July.
Netherlands-based ADC developer Synaffix has inked an agreement with fellow ADC player Qurient Therapeutics, based in South Korea, to develop a dual payload ADC. These are designed to deliver two cytotoxic agents to kill cancer cells. The collaboration will utilize Synaffix’s anticancer technology and Qurient’s CDK7 inhibitor to target unmet medical needs in solid tumors. The latter will now have access to Synaffix’s antibody conjugation platform. The financial terms were not disclosed.
Meanwhile, Adagene, an antibody developer in China, and California-based cancer drug discovery company Exelixis have plans to develop the third ADC in their continued partnership, which began in 2021. Using Adagene’s SAFEbody technology platform to generate a masked monoclonal antibody, the two will create an ADC that works against a target selected by Exelixis. The financial terms were not disclosed.
Moreover, Taiwanese biologics company Mycenax and Japanese research company spun out of pharma giant Takeda, SperaPharma, want in on ADCs too. The alliance will leverage Mycenax’s biologics capabilities as well as Spera’s expertise in chemistry, manufacturing, and controls (CMC) to develop ADCs. The financial terms were not revealed.
RNAi gaining ground in biopharma partnership circles
In the RNA interference space, two licensing deals stood out in September 2025. Chinese startup Argo Biopharmaceutical has granted an option to license the rights to two discovery-stage molecules to address conditions caused by an abnormal amount of fat molecules in the blood such as severe hypertriglyceridemia and mixed dyslipidemia to Swiss giant Novartis. It has also offered a right of first negotiation to its small interfering RNA (siRNA) BW-00112 (ANGPTL3), which is currently in phase 2 in the U.S. and China. Plus, another one of Argo’s siRNA candidates in IND-enabling studies is up for grabs for Novartis. Argo will reel in $160 million upfront and is eligible to receive up to $5.2 billion in milestone payments.
In its third deal last month, Novartis collaborated with California-based Arrowhead Pharmaceuticals for the latter’s preclinical stage siRNA therapy for the treatment of synucleinopathies, a group of neurodegenerative diseases characterized by the abnormal accumulation of alpha-synuclein protein like Parkinson’s disease. Arrowhead will haul in $200 million upfront and is eligible to receive up to $2 billion in milestone payments.
Small molecules: the usual licensing favorites
Hengrui Pharma penned its second deal of September 2025 with American biotech Braveheart Bio. Braveheart will attain exclusive global rights to develop, manufacture, and commercialize the phase 3 small molecule HRS-1893 to treat hypertrophic cardiomyopathy, a disease in which the heart muscle becomes thickened. The deal excludes development in China, Hong Kong, Macao, and Taiwan. The Chinese biotech will snag $65 million upfront and is eligible to draw in up to $1.013 billion in milestone payments.
Moreover, California-headquartered multinational Genentech and Oxford-based OMass Therapeutics have joined forces for the Roche subsidiary to take over the latter’s small molecule program for inflammatory bowel disease. OMass will pull in $20 million upfront and more than $400 million in milestone payments.
Top biotech deals of September 2025: T-cell engagers, glue degraders, drug delivery, and gene therapies in the mix
Novartis was on a roll last month, as it signed its fourth deal in September with Massachusetts-based Monte Rosa Therapeutics, further solidifying its position in the molecular glue degraders space in its second collaboration with the company in recent times. The Swiss company has nabbed the licensing rights to an undisclosed discovery target as well as the options to license two preclinical candidates. In exchange, Monte Rosa will obtain $120 million upfront and is eligible to earn development, regulatory, and sales milestones.
Meanwhile, Massachusetts- and London-based Vertex Pharmaceuticals and California-based protein therapeutics developer Enlaza Therapeutics have united to develop T-cell engagers as well as a new type of therapy called war-lock drug conjugates, a term coined by Enlaza. These drugs differ from ADCs in that the war-lock drugs form a permanent bond with their target. These therapies will be used to treat autoimmune diseases. Enlaza will bag $45 million in an upfront payment and equity investment and is eligible to receive up to $2 billion in milestone payments.
In the drug delivery field, Amsterdam-based VectorY Therapeutics and Washington-based Shape Therapeutics have forged relations. The American company will pocket up to $1.2 billion in upfront and milestone payments in exchange for VectorY gaining access to Shape’s AAV5-derived capsid for vectorized antibodies against three targets.
Finally, Pennsylvania-based Ocugen and South Korean company Kwangdong Pharmaceutical have signed on to advance gene therapies. Kwangdong has secured the rights to develop and commercialize Ocugen’s phase 3 gene therapy OCU400 for retinitis pigmentosa, a condition that causes vision loss. The American biotech will receive $7.5 million in upfront and near-term development milestones and up to $180 million in sales milestones in the first 10 years of commercialization.
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