This panel discussion was originally published in the eBook “ Monoclonal Antibody Manufacturing Trends, Challenges, and Analytical Solutions to Eliminate Bioprocessing Bottlenecks” You can download all the articles in the series, by downloading the eBook.   Panel discussion members: Carrie Mason - Associate Director, R&D at Lonza Biologics Laura Madia - Independent Industry Consultant Alan Opper – Director of HaLCon Sales at RedShiftBio David Sloan, PhD – Senior Vice President, Life Sciences at RedShiftBio Brandy Sargent, Editor in-chief, Cell Culture Dish and Downstream Column (Moderator) In this panel discussion, we talked with industry experts about antibody process development and manufacturing. Specifically focusing on current antibody titer expectations, analytical challenges and how real time titer measurement is a game changer for bioproduction moving forward. Where is the industry at today with titer expectations and what are the best practices for measuring titer? Laura Madia With respect to expectations regarding titer over the years, what we’ve seen is a need for increased titer within the upstream development of a drug. As an industry, we have moved from the 80s where titers were closer to .2 to .5 grams per liter to the early 2000s where concentrations of titer production rose to 3 to 5 grams per liter. What we see today is a continued increase in titer concentrations, which creates a challenge to make sure that you have technologies that can accurately measure titer concentration without introducing any errors. The other thing that we have seen within the industry is the need for more data to not only understand what is happening in the tank, but also to be able to make decisions about the product as the process is running or shortly after. Lastly, it is important to consider people and resources. It has been exacerbated by COVID, but it is difficult to find people to work within the industry and there are fewer people within a production suite. This has helped to drive the need for online and remote monitoring and automation to make it easier to get the necessary measurements. David Sloan To follow up on the lack of workers, one of the things that we constantly hear from the customers we are working with is that training employees can be a real challenge and a very time-intensive process. Technologies that are easier to use and require less expertise help get people up and running and minimize errors amongst new users of a technology. Laura Madia As for the current best practices for measuring titer, HPLC is the gold standard. But HPLC presents some challenges including training and HPLC requires a highly skilled person to get accurate results. There is a need for something that is simple and easy to use when it comes to measuring titer. You will still need HPLC results for approval and decisions at the end, but to be able to monitor titer throughout the process is important. What are the challenges associated with the way that titer is measured today and what can we do as an industry to improve? Laura Madia One of the challenges is that most of the assays available today are batch processes, so that lends itself to providing a retrospective look and means that most people don’t run samples throughout the process. This is because most people save these tests until the end when they can run a batch and make it more cost effective, and it is typically a long time to result so running it during the process isn’t helpful. Systems today are more for batch process and are not set up for at-line measurement, unless you are lucky enough to be able to have an HPLC that’s dedicated to that tank. Another challenge is speed and accuracy. Many of the techniques that are offline today are longer assays because they’re running as a batch. You must wait for the entire batch, which is a long time to first result. That is where having a system like the HaLCon, which you can move online and do a simple one or two injections to get the concentration is a nice thing. To be able to move measurements online and closer to the tank with an easy to use system is critical. David Sloan One of the challenges with some technologies is that they just don’t have the dynamic range that’s required to cover from the low concentrations you see earlier in the tank to those high concentrations that you’re getting later or at the end of the production run. With a technology like HaLCon, you can measure from the low concentrations of the .1 grams per liter all the way up to the higher concentrations of 8-10 grams per liter without needing to do any sort of dilutions or serial dilutions. What it really comes down to is accuracy and how closely does it agree with HPLC and do you have the dynamic range that’s required to be able to cover the whole concentration range without needing to do multiple dilutions. As soon as you start bringing dilutions into the equation, you’re increasing the chance of error and the variability sample to sample, run to run, and user to user. If you have a technique that is user friendly and even better if it’s automated to some extent, you minimize the human aspect of it and the potential error that the lab analyst brings to the assay, thus providing a more reliable and reproducible result. Alan Opper I typically see that the instruments out there, except for HPLC, are not fit for purpose. They are used for a lot of different things. For example, there are some instruments that can only measure titer after it’s purified, not prior to purification or not in the upstream lab. There are other instruments that analyze dozens of metabolites, and they can measure titer, however, they’re using methods such as turbidity, which is not as accurate throughout the whole entire production run. Results could be anywhere from 10 to 30% off the expected value. Second, retrospective analysis. Why are we doing retrospective analysis? Why are people pulling samples at the end of the run to send it to an analytical lab? Well, it’s because the current methods besides HPLC, which takes a long time, are not very accurate. End users don’t trust the results or making process controlled decisions based on the results. Lastly, HPLC is a wonderful test, but it is complex to run. It’s often in a separate analytical lab which can take, depending on the company and whether it’s production or development, anywhere from hours to days to weeks. HPLC also requires a very well trained and well versed operator. With the HaLCon, it is a small instrument that sits directly in the lab, it takes 5 minutes to run using liquid chromatography Protein A. It is very accurate, and you don’t need to do batch methods of the cells because you could take daily samples and rest assured, you’re going to know that those are very accurate and reproducible. What benefits can be gained from real time titer measurement? Carrie Mason In the development laboratory, a lot of time you’ll do a batch study for bioreactors. You’re running small scale bioreactors to optimize the process and taking samples. The process may run 10-15 days and then you batch the samples all together and send them to get results. One of the exciting aspects of real time titer measurement with the HaLCon is seeing that it really simplifies the end use, and it allows the bioreactor operator to run a test on the HaLCon, as easy as injecting any of the other types of methodologies, they use for monitoring a bioreactor. It allows you to get titer results within the day, so now your researcher has an actual snapshot of what’s happening. They can start charting that information and see what their titer looks like in relation to all the other bioreactor parameters. That’s very powerful, because now instead of having to wait until the end when you gather up all your results and see if bioreactor one was better than bioreactor two conditions, you can now start understanding what’s happening and speed up the time to decide on what conditions are the best. In a perfect world you can use this information to start making changes in your bioreactors, to start tweaking media feeds or other conditions to get optimal titer. In the past you were just extrapolating cell growth as you know best cell growth gave you the best titer, but that’s not always what we see in a bioreactor. So, in the development lab, this gives a lot of power to the end user and now allows them to see insights in their process and make faster decisions. Looking at continuous manufacturing, you are not going to have the liberty of waiting for an HPLC result because your process is running continuously. We are going to have to have controls within that process to ensure that we’re running within the set points that we want the process to execute in. With technology like the HaLCon and it’s fast results, you could have this sitting next to your continuous process and be taking small samples across a day. This would ensure that what you’re putting into your downstream process that is coming out of your continuous upstream process is exactly what you think it is. This would ensure good process control when it comes to continuous manufacturing. Alan Opper Real time monitoring and real time data can lead to much more accurate process adjustments or real time process adjustments, which will also increase your process understanding and that will enable you in the development scheme to save a tremendous amount of time, resources and money in bringing the product to market. On the flip side, when you get into CGMP production, typically they’ll close down the bioreactor and then take the sample and measure titer. Based on the titer, they will properly load their columns, because Protein A can be quite expensive. With the HaLCon,