On a scale of 1 to 5 (1=definitely no confidence; 3=equivocal, 5=high confidence), what is your degree of confidence in setting safe doses and exposure limits for chemicals, pesticides, pharmaceuticals based solely on NAMs available today (February 2022)? (Please feel free to explain)

The spirit is not only about the toxicity the chemicals might cause but definitely, the behaviors also matter.

precedence is necessary to comment on this aspect, it will be incomplete without human data

Using human tissues in non-animal models to assess safe doses of chemicals and pesticides might be a better benchmark.

I believe that in the current state it's still not completely reliable to set safe doses and exposure limit based solely on NMAs.

Beside many disadvantages in vivo animal testing has a big advantage, namely, one does not need to know the mechanism of action to see the overall result. This is not the case for NAMs. To replace one "whole animal" test one would need a huge battery of in vitro tests and there will anyway remain an uncertainty whether all important mechanisms of toxic action where covered.

There are lists of commercial products currently available for which NAMs could be used to set limits, experience is long.

Considering there are plenty of historical animal data on safe doses, exposure limit, drug potency, these can be easily correlated with appropriate in vitro method/assay and used in development of new drugs.

I have no related experience.

We are a bit far from applying NAMs today. More work is needed in the coming 5-10 years.

Based on HBM data in vitro technologies in silico methodologies, I think the picture is complete... testing using microfluidics (OoC) is the future. Still mapping Uncertainties and map all in a WOE approach.

In some cases, this may be possible, but a replacement system must be very sophisticated and also tested and compared to current animal models.

NAMs need to be developed further and need to be standardized to increase their reliability and enhance acceptance.

And what happens when we get it wrong? Or what do we do when the regulators decide, based on NAMs, that none is best when in fact some would be best if this was determined using animal studies. Happens now.

As above

The depth and breadth of knowledge generated by testing drugs and vaccines in live animals is simply unprecedented and it may be very challenging for any artificial system to compete with this. Thus, I have limited confidence for NAM to equate or excel the limits with respect to animal experiments.

Pharma companies have started to use advanced in vitro models to evaluate the pharmacokinetics of chemicals. One example is https://journals.plos.org/plosbiology/article/authors?id=10.1371/journal.pbio.3001624

Only fir specific chemicals where the database is sufficient

Currently, the measurement of safe doses and exposure limits for chemicals, pesticides, pharmaceuticals is mainly performed by means of animal experimentation, and much time will be need to change this.

I believe we are on the path, but not there yet.

We are already doing this using our knowledge of exposure and the available in vitro models for the dermal and inhalation routes.

Much confident

That would very much depend on the context, the type of exposure, the degree with which these limits are respected...

Without living systems, distribution, metabolism, elimination... Is very difficult to predict...
Toxicities are unpredictable...

I think you don't need alot of trials to gain high degree of confidence regarding safety

The repetition of the same test, with small variations, in different regions of the planet. Followed by multicenter studies, I believe it is the best way to release any substance for direct or indirect use to the human population.

At present there is not sufficiently safe imitation of the complex interrelations of the many control entities of an entire mammalian organism by in vitro and/or in silico methods to ascertain product safety for human use.

La componente personale si dimostra sempre più rilevante:i sistemi di difesa del.nostro organismo,le cosiddette sentinelle, sono variabili sia per qualità che per quantità

This answer is case specific (see answer question #2).

See above comment.

As of today, both methods (in vivo and NAMs) should be applied. This increases costs. Who pays for this extra-work?

AS long as risk can be based on the dose-response for biological activity rather than predicted toxicity, then it will be feasible. After all, toxicologists' job is to identify safe exposures to chemicals, not sort out the mode of action.

We lack a the data for extrapolation at this time.

NAMs are appropriate for setting priorities and reducing number of animals for testing. But I think that the uncertainties in dose extrapolation from in vitro to in vivo are sufficiently large that NAMs are not an adequate replacement.

See above - there are no standardized methods for organotypic models. 2D cell cultures have been standardized but these are not mechanisatically relevant at all.

There's currently still some uncertainty regarding inter-species differences and population effects. But especially when relying more on a precautionary approach (more weight on hazard) we should be able to base assessment of effects solely on NAMs already today.

Currently, reporting standards, FAIR data, etc exists but is not yet routinely applied. Lack of open data requirements further holds back the field. Safety dossiers must become public domain by default.

The scientific knowledge and computational models are not accurate enough yet.

Uncertainty is similar (or even lower) than the NOAEL derived from animal tests

I can use knowledge of chemistry , physiology, pathology, biochemistry, medicine, vetetinary medicine and mathematics to set safe doses and exposure limits for different toxic chemical if EPA can give me grant.

Animal methods appear necessary for safety testing of some chemicals, pesticides and pharmaceuticals for human use. More research is needed to advance NAM. NAM is a broadly descriptive reference to any non Vertebrate Animals technology, methodology, approach, or combination thereof that can be used to provide information on chemical hazard and risk assessment. NAMs are functionally equivalent to “alternatives" to mammal testing.

The science supporting the exclusion of animal testing as ONE step in the evaluation of drugs and chemicals is not justified in my opinion.

I based my response based on my interpretation of this question as referring to all regulatory decisions, not just those for priority setting and for skin sensitization and the like for which alternative approaches have been developed, evaluated and applied. For, major regulatory decisions affecting large population, with potential adverse effects that have the possibility to seriously adversely impact health much more development characterization and evaluation of the alternative approaches is needed to show that they are as good if not better than the current animal testing approach and this has not happened yet and as noted above will take decades to achieve in my opinion. Also, while science is important other factors are equally, if not more important, with respect to regulatory acceptance and use such as legal, economic, social, cultural and lower case "p" politics before they will be used and this too will take decades. So in my opinion there is (near) certainty that safe doses and exposure limits for chemicals, pesticides and pharmaceuticals will be based solely on alternative approaches across the board. Though it is important to note a few have been evaluated by competent regulatory authorities and found to be fit for purpose to inform certain regulatory decisions (e.g., skin sensitivity)

We are a long way off from thinking we can rely on nonanimal testing for determining what chemicals are safe or harmful.

Existing NAM based approaches, such as transcriptomics, can be used to confidently establish biological effect points of departure.

Safety testing today is already bad enough now even with all the animal testing. Using NAMs alone would make it much worse.

Not all assessments need to be of the same depth, refinement, and scope. Depending on the exposure scenario (magnitude/duration of exposure) along with the physical/chemical and PK characteristics, and the level of uncertainty that is acceptable, NAMs could be sufficient for setting standards.

Acceptance of NAMs by regulators, especially FDA, is a necessary first step. Regulated companies trying to bring their candidate new products forward to receive marketing orders must invest $millions to conduct a combination of in vitro and in vivo tests to gain FDA approvals. Companies don't want to make such investments if FDA's whims might reject them, so they are inclined to stick to 'tried and true' conventional animal test methods, despite the serious flaws that they have been found to have.

It depends on the NAM - a TTC for example is a highly health protective NAM, so if exposure was below TTC, would have high confidence. Other NAMS like Key Characteristics of Carcinogens have low confidence - hey have been shown not to predict cancer classifications

See comment to #2.

Again, its good for screening but the tests still have massive uncertainty and the extrapolation from NAMs to whole body exposure is still not mature.

This depends on the validity of the applied test system.

I just dont think the risk assessment models have been adapted to relay on NAMs as the point of departure.

I am not quite sure we can do this right now. In general we rely on studies that have already been done, or on read across.

If we would have to rely solely on in vitro today the outcome would probably have to be extremely conservative to be on the safe side for many endpoints.

I haven't seen enough data comparing the current procedures to their corresponding NAMs.

Validation remains a problem, as does biological coverage.

Many xenobiotics interact with gut bacteria. Therefore, NAMs available today do not address real life exposure.

Understanding the complexity of human immunobiology cannot be achieved by NAMs

Small humans? Maybe not always

Combination of in vitro testing and kinetic modelling will cover many applications, use of concepts such as TTC and refined exposure assessment will also need to be integrated

Using only NAM is actually using humans as an experimental animal after marketing/using.

Even todeay full-blown animal testing by the best laboratories in the world under regulatory reviews cannot always set safe doses and exposure limits. So it is not reasonalbe to expect this of NAMs by 2035.

Again, having regulators focusing against assessing and approving the use of non-animal methods will greatly facilitate getting to this goal. There are already a number of good non-animal approaches available but lack of regulatory acceptance makes it hard to move them forward.

Dosage is not the only aspect to consider even the toxicity is dose-dependent.

If we could get COVID vaccines developed in less than a year, we can achieve anything

feel quite non-confident about the dose adjustment, mainly on its responses, and its applicability to humans.

Depends on use case and exposure risk. Also depends on how large of a battery of NAMs are applied - e.g. testing 100s of targets is probably sufficient to identify most hazards, although likely to be overly conservative. A smaller number of NAMs may not be sufficient for setting safe doses and exposure limits.

Do not agree at all

There is still uncertainty which can be great in some cases

Same as number 1

How will you set a safe daily dose based solely on in vitro data? At the very least you would need to have in vivo ADME data with blood levels, so still a need for animal testing. Besides, as mentioned above, in the absence of validated NAM's the point is moot.

I would be more confident if the decision rule (guidelines) using only NAMs was developed and published

To rely on NAMs is just wishful thinking. They can be considered alongside a range of relevant experimental data.

Not being tried.

Time of exposure depends on the objective of the study.

Limits of chemicals use are solely determined on in vivo models

All non animal testing results show a semiquantitative results. Animal tests are needed to adjust quantities.

animal testing demonstrate the actual metabolic interactions between drugs and certain organs or site of action, which can not be replaced.

See answers above. Moreover, and disconcertingly, there could be a large hazard to developing and adult humans in this NAM approach.