In Vitro vs. In Vivo Preclinical Drug Testing

Often, new drug makers come across a potential anticancer agent—and as they consider evaluating that agent further, they tend to confront this central question: Should I do in vitro or in vivo testing?

Ample studies—and even pros and cons lists—have dissected the question bit-by-bit. Put simply, the answer, like many things in oncology research, depends on my factors—from budget and timeline concerns to the type of anticancer agent and stage of research in identifying drug safety and efficacy.

With the evolution of in vivo drug testing, the screening process has overcome the shortcomings and can discern the overall effect of an experiment on a living body—but still, both in vitro and in vivo studies play an appropriate and very important role in different situations. Let’s walk through them:

What Is In Vivo Preclinical Drug Testing?

As a Latin term that means the “whole body,” in vivo refers to tests that are performed in a live environment of a whole body—usually on live animals such as murine models.

This step supports drug safety testing before the launch of human clinical study—but there are challenges, too. Namely:

  • In vivo testing is generally more expensive and time-intensive than in vitro studies.
  • For obvious reasons, this form of testing is subject to strict regulation and compliance standards.

What Is In Vitro Preclinical Drug Testing?

In vitro, on the other hand, means “in the glass” in Latin, and refers to just that—when live cells are removed from the organism and tested in an artificial, controlled environment.

Unlike in vivo, in vitro bypasses drug safety in favor of assessing drug efficacy.

When to Use In Vivo Testing

While in vivo testing is more specific and reliable, researchers need to balance the benefits with the cost and length of time to complete these tasks. If both budget and time are on your side, it’s certainly a smart step in any preclinical strategy.

When to Use In Vitro Testing

In the last several years, in vitro testing has served as the primary testing model for cancer drugs. While it does help bring new drugs to clinical trial faster and with less cost, it doesn’t give the best picture of how a patient will react to the drug—which makes clinical trials especially important.

So Which One is Best?

In an ideal scenario, doing both is best. Researchers would launch an anticancer project under in vitro clinical review, and if results show anticancer activity—they would follow-up with a more robust in vivo strategy.

But there’s a caveat—the preclinical tools involved in both in vivo and in vitro study should support well-characterized cell lines and ample model selections, even for rare cancers, a point made by an essay author in Oncoscience in 2015.

Two years later, another author reinforced those arguments in Oncotarget—adding that strategic errs such as data misinterpretation and lackluster study design add to the growing problem of anticancer drug development failure.

So regardless of which path you choose—in vivo only or in vitro combined with in vivo—the project can’t succeed without a robust preclinical strategy and an arsenal of tested preclinical tools.

Get Started

Need help with your preclinical strategy? Contact TD2 to get more information about in vivo and in vitro testing capabilities ready for immediate use.
Need help with your preclinical strategy? Contact TD2 to get more information about in vivo and in vitro testing capabilities ready for immediate use.

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About Translational Drug Development (TD2)

TD2 is an oncology development organization that provides innovative services for oncology-focused companies. Using a dedicated team of professionals with broad experience and understanding in drug development, TD2 is uniquely positioned to support improved and accelerated development of medicines for life-threatening oncology diseases. TD2 applies rigorous and high-throughput translational preclinical development, combined with regulatory affairs expertise, to customize clinical trial design and execution. TD2’s suite of capabilities encourages the timely selection of patient populations who are most likely to benefit from a new agent, and the rapid identification of clinically significant endpoints. TD2 is committed to reducing the risks and uncertainty inherent in the drug development process and to the acceleration of patient access to promising treatments. For more information, visit

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