Clinical trials: From bench to bedside to improve outcomes for cancer patients

Clinical trials are crucial to understanding how drugs and therapies work, how safe they are in humans, and how effective they are in treating cancer. They are vital for making advances that improve patient outcomes, and the prize for companies – regulatory approval to market a treatment – is huge. Hardly surprising, then, that the clinical trial phase accounts for around 44% of R&D spend on drug development[1], which in 2021 was estimated at USD 238 billion globally.

In oncology, clinical trials involve significant risk[2]. According to the Journal of the National Cancer Institute, only 38% of Phase 3 randomized controlled clinical trials in oncology achieved statistically significant results[3]. While the report attributed this result to “investigators consistently making overly-optimistic assumptions regarding treatment”[4], in reality the story is more complex, and starts long before a drug reaches patients.

The long and winding road to market

Clinical trials in oncology are more time-consuming than in other therapeutic areas. Trials planners need to take into account a complex set of factors including tumor heterogeneity (including disease staging), biomarkers, patient eligibility criteria, clinical endpoints that best mimic readouts for efficacy, as well as follow-up timelines. As a result, oncology clinical trials often rely on novel designs: basket trials, for example, test one drug in several tumor indications (this is the approach that invIOs has taken with its APN401 cell therapy candidate).

For precision cancer treatments such as invIOs’s novel cell therapies, which are personalized to each patient, success involves working closely with multiple stakeholders. Trial protocols must be well designed; trial sponsors have to comply with the specifications of regulatory bodies, as well as common standards such as GCP, to ensure that the highest standards are maintained. Drug developers must develop robust processes and structure the trial design to ensure that the data gathered during the trial is consistent and clear. Finally, trial execution must be efficient and effective, with accurate data collection, monitoring and analysis.

The future of clinical oncology trials

Despite these challenges, oncology is one of the leading areas for innovation in the growing global therapies market. A record 30 oncological novel active substances were launched globally in 2021, and a total of 159 since 2012. And the pace of innovation shows no sign of slowing, with the trial pipeline for immune oncology therapies growing by 233% in 2017-2020[5].

This staggering growth has been driven by years of fundamental cancer research that have yielded pioneering discoveries such as immune checkpoints – like the well-known PD-!/PD-L1 axis or Cbl-b, which invIOs targets with APN401 and INV441 – and other advances in cell engineering including chimeric antigen receptors (CARs)[6].

The revolution in cancer treatment is being paralleled by similarly seismic shifts in the design, pre-authorization and execution of clinical trials. In immune oncology, greater patient stratification and more nuanced efficacy measurements are becoming the norm. As treatment strategies and trial design continue to advance, it is vital that regulatory approaches and education of medical staff, hospital workforces and key opinion leaders (KOLs) also evolve so that patients can benefit from safe, well tolerated and highly effective treatments.

With more and more novel treatments entering clinical trials, the potential for finding treatments for rare and complex cancers continues to increase. Precision and individualized therapies such as those being developed by invIOs have the potential to transform the lives of patients, offering new tools to fight cancers. Optimal clinical trial design and execution will be key to making these breakthroughs possible.

Preclinical testing: Start early to solve the problem

Before a cancer therapy is deemed suitable for clinical trials, preclinical proof of concept, safety and tolerability, as well as a potential target indication, must be demonstrated in a range of in vitro tests and in vivo models. Failures further down the line in clinical trials can sometimes be attributed to research gaps at this early stage – particularly if preclinical models failed to accurately represent the human tumor and its microenvironment, which is of particular interest for immune-oncological therapies for solid tumors. Recent advances such as improved 3D models[7], studies of novel treatments in organoids and the use of artificial intelligence (AI) can be employed to streamline the process and reduce overall risk[8].

Phase 1: Safety first

Unlike most diseases, Phase 1 oncology trials involve cancer patients rather than healthy volunteers. This is often based on the balance of risks and benefits associated with cancer therapies, especially in indications with high unmet medical need. The primary goal of Phase 1 trials is to establish a safe dose regimen and a potential maximum tolerated dose (MTD) in a small patient cohort, with in-depth analysis of systemic effects being important in determining whether the treatment should progress to a larger scale trial. Initial chemistry, manufacturing and controls (CMC) processes are also completed at this point, so that issues can be identified and rectified in time for later approval and larger scale development of GMP batches.

Even despite prior preclinical testing, some Phase 1 clinical trials highlight safety concerns that cause drug developers to revise their plans. While severe side effects discovered in Phase 1 trials can eventually be attributed to factors such as the administered dose, health authorities and drug developers may agree to conduct more stringent dosage assessment or establish closer monitoring at this early stage. Additionally, there is sometimes the option to pursue alternative trials, possibly in a subset of patients that are more likely to benefit from the novel therapy.

Phases 2 and 3: Scaling up to assess impact

Once a safe dosage has been established, treatments can then progress to Phase 2 and Phase 3 trials in patients deemed eligible for treatment. Phase 2 trials focus on efficacy, while Phase 3 studies compare the therapy against the current standard of care in a larger cohort at the final dose. These trials are vital but costly: A report in JAMA Internal Medicine estimated the median cost of a Phase 3 trial at approximately USD 19 million (data across a wide range of indications)[9], based upon an analysis of 138 “pivotal” drug trials for novel medicines with a median of 488 patients enrolled per trial. Novel, personalized cell and gene therapy approaches may even top these numbers.