The biggest biotech funding rounds in September 2025

The companies uniQure, Dianthus Therapeutics, and Mineralys Therapeutics bagged the biggest biotech funding rounds overall in September 2025 across private and public funding types. In this article, we break down last month’s private and public fundraising activity, looking at the largest rounds in more detail.

Private biotech funding rounds in September 2025

First, let’s take a look at the private biotech investments in September 2025, breaking them down by value, location, funding type, and therapeutic subsector.

Biggest private biotech funding rounds by value

We can see from the table below that, in September 2025, it was Odyssey Therapeutics that managed to raise the biggest private biotech round of the month, as it bagged $213 million in series D funding. According to the company, the proceeds will support the advancement of its portfolio of clinical and preclinical candidates, which are designed to precisely treat the drivers of complex autoimmune diseases.

In second place, meanwhile, was Crystalys Therapeutics, which launched with $205 million in series A funding to transform gout treatment. To achieve its aim, the company has partial rights to a URAT1 inhibitor called dotinurad, which has already been approved in Japan, China, the Philippines, and Thailand. This financing round will now allow Crystalys to advance the candidate into global phase 3 trials toward regulatory approval and commercial launch.

In third place, Treeline Biosciences also raised an impressive amount of money, bagging $200 million in a series A round to bring its total funding to date to $1.1 billion. At the same time, it also announced its first clinical trials: phase 1 studies for two internally discovered programs, TLN-121 and TLN-372, and a third in-licensed program, TLN-254, in oncology indications. 

Private biotech funding rounds by location

Once again, North American companies excelled in the private biotech standings last month, bringing in $1.032 billion from eight rounds. Europe also returned to second place after a bad month in August, as companies in the region brought in $253.8 million from six rounds in September, while Asia-Pacific companies raised $109.4 million from three rounds.

Private biotech funding rounds by funding type

Although last month, more series B rounds took place than any other type of round, with six in total, the most money was raised through series D funding, despite there being just three rounds of this type; altogether, the companies that completed series D rounds – which included the frontrunner of last month, Odyssey Therapeutics – brought in a total of $488 million. Meanwhile, series A rounds came second in the rankings both in terms of total rounds and value, with $439.4 million being raised from four rounds.

Private biotech funding rounds by therapeutic subsector

When looking at the therapeutic subsector standings from last month’s private biotech fundraising, we can see that the subsector of oncology achieved the most rounds, with four in total, and brought in the most money, with $324 million. Drug discovery and inflammatory diseases came joint-second in terms of the number of rounds, with three each; however, it was the inflammatory disease subsector that came out on top when looking at the amount raised, as companies in this field brought in $281.4 million, versus the $159.8 million raised by drug discovery companies.

Public biotech funding rounds in September 2025

Now, let’s check out the public biotech fundraising rounds that occurred in September 2025, breaking them down by value and therapeutic subsector.

Public biotech funding by value

In the public biotech funding rankings in September 2025, we can see that gene therapy company uniQure came out on top after it brought in $345 million from a public offering. The company said that it intends to use part of the net proceeds from the offering to fund the potential commercial launch of its current lead candidate AMT-130, which is being developed for Huntington’s disease. 

Dianthus Therapeutics came second in the standings last month after raising $288 million from a public offering, which it will use to advance its preclinical and clinical development activities, and Mineralys Therapeutics came very close behind in third place after bagging $287.5 million from a public offering, which it will use to fund clinical development of its lead candidate lorundrostat, including research, development and manufacturing, and pre-commercialization activities.

Public biotech funding by therapeutic subsector

Oncology players also came out on top last month in the public biotech fundraising landscape when looking at the number of rounds, as they bagged $228.5 million between them from four rounds. However, it was endocrine disorder companies that raised the most money overall, bringing in $374.9 million from just two rounds.

Month-to-month comparison of biotech fundraising

Below is a graph showing a month-to-month comparison of private and public biotech fundraising, looking at the total amount of money raised per month in 2025.

September 2025 proved to be another very strong month for public biotech fundraising, where for the third time this year, it outperformed private biotech fundraising over the course of the month. Additionally, public biotech fundraising also achieved its second largest total of the year so far, as $2.442 billion was raised from public rounds. Private biotech fundraising, meanwhile, achieved a better total than it did in July or August.