Merck & Co., Inc. (MRK) Earnings Call Transcript & Summary

Good afternoon, everyone. My name is Clémence Justine. And today, we will talk about challenges and improvements in cell line development, how to achieve a high productivity on a reduced time line. First of all, I will present to you the BioReliance End-to-End Solutions, and our CHOZN program, then we will discuss our -- today's challenges and our answers to them. And then I would like to share with you the improvement that we want to implement on the cell line development process to finish via conclusion. The BioReliance End-to-End Solution is divided into several sites worldwide, each with its own specific activities, including a few biodevelopment centers at Boston, Bordeaux and Shanghai. The cell line development for external customer projects is available in France and in China. We cover all your process developments and clinical supply needs with one package, from the cell line development, cell banking, to analytical and process developments, manufacturing and testing. When your project is ready to go to market, we also support your commercial manufacturing plan. You have the freedom to take and transfer anytime to anywhere. If you want to manufacture in-house, we do facility design, equipment specification and commissioning. We train the staff to make sure that they are ready to take over after takes and transfer. We make sure you are generally ready. Concerning the CHOZN program, we have 2 cell lines which are implemented in each biodevelopment center. For each cell line, protocols in the cell line traceability are available. The expression vector and the media impacts are defined. For the CHOZN CHO-K1 cell line, which is multiplied after the glutamine synthetase activity, we use fluorescein as selective pressure. It has good growth performance, thanks to its low-to-blink time, and a short-term process is available. For the CHOZN GS cell line, which is depleted of its glutamine synthetase activity, thanks to the use of zinc finger technology, the drug selection is needed. We just remove the glutamine from the medium. It gives high stability for the clones in production processes. The short-term process to these are ongoing. For the cell line development process, we have 2 offers. The platform process for our cell line development includes 4 weeks of expression vector construction. During these steps, the old cell line is probed and extended to wind time. When cells have recovered from the frame, the transfection is performed and stable millipores are generated. The best millipores are selected after a pre-round of screening in the batch of evaluation. The best millipores are then probed, and a single cell clone via a limiting-dilution cloning and the same free one in upstreaming are performed to select the best clones. The cell line stability is then assessed by a limit of cell stability over a 60-population doubling level and will conclude master cell bank is generated. The short-term process called direct single cell cloning is available for the CHOZN CHO-K1 cell line, in which the millipore step is replaced by a single pool generation. This pool is for a single cell clone at a specific time during its recovery. I will come back to this point in 2 slides. Concerning the clone generation, it remains unchanged compared to the standard process. During these talks, I will discuss about a different pool, and I just want to make sure that it is clear the difference between each pool. So we have a stable pool, the stable mini-pool and a direct single cell cloning pool. At the time of transfection, the composition of each pool remains the same, meaning that we have untransfected cells. And as we do not use the targeted acceleration, we have low, medium and high producers. The only difference at this step is that for the stable mini-pool, we divided the diversity into a small volume, meaning that inside each mini pool, the diversity is reduced. At the time of limiting-dilution cloning, all the untransfected cells will have died. For the stable pool, the diversity will have evolved a lot. Indeed, for a clone with a low doubling time, their proportion into the population will have increased. On the contrary, for the clone with a high doubling time, their proportion into the population will have decreased. This means that the diversity will be reduced. Among the remaining mini pool, the one with the best titer will be selected to increase the chance to find the best producers. For the pool from the direct single cell cloning, the limiting dilution will be performed after around 2 weeks. This means that the recovery has not ended. The idea is here to preserve the diversity among clones with different growth rates, while making sure that cells are ready to undergo a limiting dilution cloning. The stable pool was the original process. Around 2010 appeared the stable mini-pool strategy. Nowadays, new strategies are emerging, such as the direct single cell cloning, to answer to our new customer needs. Today, we have 3 main challenges, which are reducing the time line, while maintaining a high productivity and a stable cell line. To adjust time lines, we perform the filtering and expansion of parental cell line in parallel of the construct generation. This enabled a gain of 2 weeks. We also gained 10 additional weeks by the separation of the stable mini-pool generation. To ensure high productivity, we played up to 1,300 clones, and they are screened via a free screening step in batch and fed batch mode to find the best producers. To ensure the cell line stability, we perform a stability to see over a 60-population doubling level, and this makes high-clone stability in production processes. But we want to do more than that. To reduce project time lines, some steps might be performed in parallel depending on customer needs. Before starting the project, discussions occur to find the best option, taking into account customer timing requests and risk mitigation. As an example, the process development could be performed on the pool where the clone generation is carried out. In the standard offer, the clone stability study performed in parallel of the USP development is already implemented. COVID created an unprecedented crisis, where the need for diagnostic reagents and treatments are becoming urgent. In such context, the whole scientific community had to rethink the real rudimentary needs to provide as fast as possible biological material. As a consequence of the development of a new molecule, the requirements are a producing time line, a GMP production and the minimum associated testings for the drug substance release. Here is an example of what we can propose to a customer in this case, starting from the cell line development, to the drug substance in 1 year, without any process development. Indeed, the process development is not a requirement, but a way to increase the productivity and process consistency. Now let's focus on what we can do on the cell line development timing. After the reduction of 10 weeks, thanks to the implementation of the direct single cell cloning, we hope to shorten again some steps. By reducing the pool creation by 1 week and putting in place the 96 deep-well plate and the 24 deep-well plate cell culture, the global process could be reduced by 5 additional weeks. With any time addition, an optional fit screening is also possible at 24 deep-well plate stage. In order to do so, some studies have started and overall will take place all along this year. Concerning the transfection step optimization, a transfection media and reagent screening study is ongoing. Indeed, in the direct single cell cloning, cells will undergo in less than 3 weeks a transfection, the selective pressure and the limiting dilution cloning. In order to survive through these stressful steps, that will have to be in the best condition. We also need to reach the appropriate cell culture condition to ensure cell recovery. We will be focused on cell density, cell culture parameter and the selective pressure addition. In order to optimize the single cell cloning step, as already mentioned, we need to determine the optimal timing to ensure plan diversity, taking into account cell recovery. We also want to implement new technologies to reduce lab work and increase capacity. I will come back to this point in a few minutes. Today, the determination of clonality is assessed by 2 independent technicians, and this is time-consuming. In order to reduce this time, we want to implement fluorescence-assisted monoclonality determination, and this study will start soon. It will also strengthen the proof of monoclonality. To increase predictability from scale-to-scale, we try to replace one of our productivity testers from in batch via fed batch mode. Indeed, our last productivity test is performed in agitated spin tube with EX-CELL Advanced CHO Fed-Batch Medium and with the use of EX-CELL Advanced CHO Feed 1. We tested in 96-well plates and in 6 well plates a different condition in static mode. Some conditions were performed in EX-CELL CD CHO Fusion with or without EX-CELL Advanced CHO Feed 1, and other conditions were performed with EX-CELL Advanced CHO Fed-Batch Medium with or without the EX-CELL Advanced CHO Feed 1. In order to assess the predictability, we choose the correlation as an indicator. A correlation from the spin tube to the other scale will be considered as a good correlation when the value is close to 1. A value close to 1 means that the ellipse in well will look like a line. And no correlation, meaning a correlation of 0, the ellipse will look like a circle. Here, if we look at the scale, we can see that the 6-well plates correlate more with the spin tube. This was an expected result as a screening step has already been performed. But if we look at during the 96-well plates or among the 6-well plates, all the conditions, we can see that the ellipse shapes remain the same. This means that the predictability has not been increased by adding EX-CELL Advanced CHO Feed 1 medium or using the EX-CELL CD CHO Fusion medium instead of the EX-CELL Advanced CHO Fed-Batch Medium. We then decided to test -- to replace the 6-well plates for 24 deep-well plates. On the left, you can see a graph where we have the 6-well plate data compared to the spin tube data, and we can see that we have a correlation of 0.64, with a good p-value. When we replace the static 6-well plates for unoptimized agitated 24 deep-well plates, we can see that the correlation has increased to 0.73, with a remaining good p-value. This means that the predictability has been increased from scale-to-scale. With this, we need to improve small-scale cell culture conditions to ensure the right clone selection. And for that, we need to adapt the cell counting to small cells. This -- both studies are ongoing. Concerning the fit screening during the cell line development, the idea is to test productivity capacity with a predetermined platform in order to assess cell line potential, reproduce cost and no time addition as performed in parallel of cell banking. Here, you can see some results obtained in a bioreactor, where we tested a different platform on one clone. You can see that 2-platform testing gave a better titer compared to the standard platform. This result is not always the same for clones, so that's why, for each clone, we have to determine what is the best platform. The platform frame will be a part of the talk presented by Kimberly Mann during this week. By this way, you can see that we can reduce the time line, but also increase the productivity. In order to increase productivity performances, it is also possible to use a cell seeder or a cell sorter. The cell seeder will enable a reduction of lab work and increase capacity. The cell sorter will enable a fast productivity test to select the most promising clones, but the productivity test has to be adapted to each type of molecule. In this, today's technology are mainly focused on monoclonal antibody and Fc-fusion protein. But some solution has to be found for the older molecules. On the slide, you can see the results of the study, where the objective was to compare the productivity of clone generated either with a cytokine or with our current process by limiting dilution cloning. What we can see is that the specific productivity is higher for the clone generated with the cytokine. Studies are ongoing to screen the different devices on the market. To increase our productivity performance, it is also possible to test different signal peptide. The generation of a signal peptide library is ongoing and will be available for both cell lines. We also want to work on the old cell line. This work is ongoing, honestly, this, and we are looking for a specific cell behavior, such as low doubling time or low lactate production levels. It is also possible to improve the gene integration into the genome via the use of ubiquitous chromatin-opening element technology. This will be also a part of Kimberly Mann's talk this week. We also have a targeted integration research project ongoing. Even if we want to improve some steps, we have some remaining challenges that are common to the whole scientific community. We need to better characterize our clone. And for that, we need to add clone quality testings earlier in the cell line development process. We also need to add DNA sequencing and gene copy number analysis before the final clone selection. In order to do so, analytical methods should be adapted to the volume and timing constraints. One of the big challenges is that more and more exotic molecules are emerging. In order to be able to screen a large amount of clones, we need the miniaturization and the full automation of the cell line development platform. The development of analytical methods at miniscule is also a requirement. To conclude, we plan a cell line development reduced by 15 weeks for 2021, and we want to integrate miniaturization to perform right screening at small scale. We also need to integrate new technologies adapted to all types of molecules. I'd like to thank the BioReliance End-to-End Solutions and more particularly, our Senior Director, Global Delivery and Sales, Sébastien Ribault, and all the development departments. If you are interested to learn more about us or to work with us, you can reach out to Arthur Misyan, our Global Head of Business Development. I will be available if you have any questions.