The FDA has gone on to publish new guidance, which is aimed at reducing or stopping toxicity studies of monoclonal antibody-based drugs in non-human primates – NHPs, in the latest stage of a continuous effort in order to decrease animal testing of new medicines.
The new draft guidance goes on to remove the need for single-target or monospecific antibodies, which need to be tested for six-month toxicity in NHPs such as cynomolgus macaque or rhesus monkeys as well as marmosets.
Rather, antibody developers can go ahead and extrapolate from three-month studies pertaining to non-rodent species such as NHPs, dogs, and also mini-pigs, supplemented by a weight-of-evidence – WoE risk evaluation that’s based upon the data from similar antibodies.
It is worth noting that the eight-page document notes that, unlike the small-molecule drugs, antibodies are not metabolized by way of biotransformation in the liver; hence, they do not carry the same risk of generating the potentially toxic metabolites.
The guidance does not go on to apply to multispecific antibodies, antibody-drug conjugates, or even drugs based on antibody fragments, as per the FDA.
Earlier in 2025, the regulator remarked that it intends to decrease or replace animal testing of numerous medicines, including the likes of antibodies, with certain other methods that it hopes are going to be more relevant when it comes to human physiology.
Among the other options that are under consideration are artificial intelligence – AI and computational methods, which could as well forecast safety in silico, and human cell lines as well as organoids, which apparently are organ-like structures that are made from human cells as well as tissues, which could as well serve as lab models.
There are similar efforts that are being put forth so as to decrease animal testing of new medicines, and these have also been announced by the EU as well as the UK in recent times.
As per the FDA Commissioner, Marty Makary, they are delivering on their roadmap commitment in order to eliminate animal testing needs in drug assessment and their promise to speed up cures and meaningful treatments for Americans.
He further said that modern science has given a far more effective as well as humane way of assessing drug safety than going ahead with animal testing. He added that this reform may go on to decrease the amount of time it takes to get a drug to the market and lower the research and development expenditures, which can lead to much lower drug prices.
Notably, the FDA also estimates that a typical non-clinical programme having a monoclonal antibody product could also include over 100 NHPs, incurring costs of around $50,000 per animal. But many products that clear toxicity testing within animals do not get the FDA approval, majorly because of safety or efficacy challenges within humans.
Richard Pazdur, who may be retiring from the position of director of the Center for Drug Evaluation and Research of the FDA just a few weeks after starting the job, remarked that knowledge-based risk evaluation of toxicity goes on to reflect scientific progress along with their responsibility to make use of the most effective tools when it comes to drug evaluation.
