Recent levelling-off signals a maturing sector, says Ian Lloyd, Senior Director, Citeline.
The pharmaceutical R&D ecosystem has never been bigger. The global drug pipeline now approaches 24,713 active targets, with numbers increasing 145% from January 2010 to January 20251 – a new peak for the industry.
At the heart of this ecosystem is oncology. Over the past decade, the therapy area has been at the forefront of many pharma companies’ research agendas, fuelled by scientific advances and high unmet need. The number of oncology drugs in development hit a record 9,476 in early 2025, rising about 3.7% from the prior year.2 By comparison, the next-largest field (neurology) has fewer than half as many candidates, showing just how essential oncology is as pharma R&D progress continues its upward trajectory.
Quantifying this in terms of the wider R&D pipeline, oncology now commands an outsized 39.7% share. While pharma majors continue to invest in cancer, market dynamics are shifting the primary battleground for pharmaceutical innovation today, so pharma investors are increasingly questioning whether this dominance will continue.
A peak or just a plateau?
Amid oncology’s long ascent, 2025 brought a subtle but noteworthy shift: For the first time in ten years, oncology’s pipeline share ticked downward. Cancer-related projects made up 39.7% of all pipeline candidates as of January 2025 – just narrowly below the 40.1% observed the year before.
This small drop interrupts a decade-plus trend of oncology increasing its slice of the R&D pie. And it raises the question: Have we reached peak oncology?
One might point out that an inflection point was inevitable; oncology could not command an ever-growing share forever. Indeed, oncology’s growth rate has lately lagged the overall pipeline. In 2024 the global pipeline expanded 4.6%, outpacing cancer’s 3.7% uptick.
Meanwhile, a few other areas are now surging, loosening oncology’s dominance. Notably, anti-obesity drugs have exploded onto the scene. The number of active anti-obesity projects jumped over 35% last year,3 driven by the success of GLP-1 therapies.
Such trends suggest that oncology’s commanding role, while secure, may be plateauing as the industry’s attention diversifies slightly toward metabolic diseases, neurology, and others. Still, at nearly 40% of all pipeline drugs, cancer R&D remains colossal. It’s too early to declare a sustained downturn for oncology, but this levelling-off signals a maturing sector. The coming years will reveal whether 2025 was a brief pause or the start of a gradual decline in oncology’s pipeline share.
The broader R&D context: rare diseases and pipeline progress
Oncology’s trajectory must be viewed considering broader R&D trends. The overall pipeline continues to grow in size as well as complexity. A significant portion of new R&D focus lies in rare diseases, which now account for almost one-third of all pipeline drugs. In 2025, 7,721 drugs are in development for at least one rare disease, up 7.4% from the prior year.4
Notably, oncology overlaps heavily with this trend – many oncology agents target rare cancers – giving cancer the largest share of rare disease projects as well. This reflects pharma’s pivot to more specialised, targeted therapies across the board. The pipeline is also advancing in terms of development stages. After a period of stagnation, the number of drugs at the Phase III development stage rebounded in 2024, rising by over 100 candidates (an 8.8% increase).5 This means more oncology drugs (and others) are progressing into late-stage testing, a positive sign that earlier investments are maturing. However, these shifts come with challenges.
Clinical success rates have been trending downward, especially in oncology.6 Cancer programs have a lower probability of approval (around 4–5% from Phase I) than most other disease areas, which drags down overall success averages. Additionally, the massive volume of trials is straining patient recruitment. The biopharma pipeline’s rapid expansion has not been matched by an equivalent growth in patients available for clinical studies. Oncology and rare disease trials, often narrowly targeted, face some of the slowest enrolment rates in the industry. These factors temper the optimism around an ever-growing pipeline – more isn’t automatically better if bottlenecks prevent those drugs from reaching the finish line.
Oncology at an inflection point
All told, oncology R&D in 2025 sits at a fascinating juncture. By scale, it remains the juggernaut of pharmaceutical R&D, with thousands of cancer therapies in play and virtually every big company and biotech vying for a slice. The oncology pipeline’s sheer size and breadth – spanning immunotherapies, cell/gene therapies, radiopharmaceuticals, and beyond – has driven remarkable progress, with significant numbers of new cancer drugs launched in recent years.
Now, the data hint at a possible inflection: Oncology’s share of the pipeline has flattened, and other therapeutic areas – from rare metabolic diseases to neurology – are accelerating. This could mark the start of a more balanced distribution of R&D effort in the long term.
Even so, one year of modest decline is not a definitive trend. It may simply reflect a cyclical correction or reporting artifacts rather than a lasting pivot away from cancer. Oncology’s pipeline still grew in absolute terms and continues to yield the lion’s share of novel therapies and investments. In fact, industry appetite for oncology innovation (e.g., next-generation immunotherapies and precision medicines) remains intense, as evidenced by substantial oncology deal-making and clinical activity, including AbbVie’s almost £7.5 billion acquisition of ImmunoGen, and Pfizer’s £31.8 billion acquisition of Seagen to acquire stronger ADC portfolios.
Going forward, stakeholders will be watching closely to see if 2025 was a turning point or a plateau. If oncology’s share continues to slip in coming years, it would signal a strategic broadening into other fields. If it resumes growth, oncology will further cement its role as the engine of pharma R&D. Either way, oncology R&D is entering a new phase – one defined not just by its enormous scale, but by how efficiently that investment translates into medical advances for patients.
References
1 https://www.norstella.com/patient-availability-conundrum/
2 Citeline, Pharma R&D 2025, https://www.citeline.com/rd25
3 Ibid
4 Ibid
5 Ibid
6 https://insights.citeline.com/IV154612/Why-Are-Clinical-Development-Success-Rates-Falling/
