Meeting tomorrow’s biopharmaceutical process needs

The introduction of biologicals has necessitated the rapid development of new biopharmaceutical process technology. Andrew Bulpin, Executive VP, Process Solutions, EMD Millipore, talked to Manufacturing Chemist about supplying this fast-moving sector and future process developments

Process technology has evolved rapidly from laboratory to production scale

Since the start of their development in the 1970s, biologic therapies have transformed the lives of millions of patients with serious illnesses. Today, biologic agents continue to outpace small molecule medicines in terms of market growth. The latest Visiongain study predicts the world market for biologics will reach US$270bn in 2019, with strong revenue expansion from 2015 to 2025.1

A whole life science industry has grown up around their development to provide the building blocks, production and analytical equipment and services required for their manufacture. Process technology has evolved rapidly from laboratory to production scale, and a number of major suppliers have grown alongside it.

EMD Millipore is one of those companies. Founded in 1954, the Millipore Filter Co started as a filtration company, pioneering the use of membrane technology. Since then the company has increased its product range and acquired new businesses. In 2010, the Millipore Corporation was acquired by Merck KGaA, Darmstadt, Germany and operates under the brandname EMD Millipore in the US and Canada (and is known as Merck Millipore in the rest of the world).

Today, as the life science division of Merck KGaA, its offering includes more than 60,000 products and revenue stands at €2.6bn, and a growing part of that is biopharmaceutical technology and services. Andrew Bulpin, Executive VP, Process Solutions, says the company is always looking for better ways of doing things so it is important to understand the process from end to end. The biologicals route is far more complex than small chemical process routes, involving: cell line development, cell expansion, cell culture, harvest clarification, chromatography, virus filtration, ultra filtration, sterile filtration, final fill and finish, quality assurance and characterisation.

Andrew Bulpin

‘Strategically Merck KGaA, Darmstadt, Germany wants to be a leader in all of these,’ says Bulpin. ‘In this industry, if you are not on the podium, the pickings are thin. Customers will have one approved vendor, maybe two, but rarely three. If you are not one, two or three, you are not going to make it work.’

Despite its size, the company is happy to serve all potential biopharma customers, ranging from small virtual companies to established multinational biotechs. It also aims to serve all geographies, including the emerging markets. The main biotech growth markets are India, China and Korea, says Bulpin, but some Eastern European countries, such as Turkey, and Latin American markets, such as Brazil and Mexico, look promising.

The needs of this client base vary, however: ‘In the established markets, companies that have done their apprenticeship and are on their second generation molecule have the infrastructure and know-how to process it; they are looking at the process step-by-step to find what is going to be the most efficient fit for their molecule. They will look at what is out there and choose the product that gets the best results, most technical support and is easy to validate.

‘In the emerging markets, companies may be developing their first molecule and may not have the same infrastructure or the institutional knowledge of some of the established companies; they are looking for somebody who can develop a whole process train. In this situation, we are talking about end-to-end solutions and they won’t necessarily be looking to optimise to the “nth” degree. In many cases they just want to get their molecule to the next level and speed is important,’ Bulpin explains.

With many biologicals emanating from small biotechs, single use technology is readily suited to use in the lab and thus has gradually moved into the pilot factories and the production space

An immediate question is, does the customer want stainless or single-use (SU) equipment? With many biologicals emanating from small biotechs, SU technology is readily suited to use in the lab and thus has gradually moved into the pilot factories and the production space. The cheapness of SU also takes away some of the capital risk.

However, despite its capital costs, stainless steel still has its role to play, says Bulpin: ‘My personal opinion is that up to about 2,000L, SU makes most sense: it gives more flexibility, less capital investment up front and gives a certain autonomy. Above 2,000L, in all honesty, stainless is more economical.’

An example of where the company has looked to improve its offering is in scaled-up SU bioreactors. ‘We have a 3L bench scale, a 50L, a 250L and now a 2,000L – the biggest out there – and we will have a 1,000L on the market soon. We have taken our time, seen other models and spoken with customers to see what we can fix for them.’

An example of where the company has looked to improve its offering is in scaled-up SU bioreactors

The latest 2,000L bioreactor vessel is a case in point. Unlike conventional models it does not require a hoist for access at the top. Instead, the base is on castors and acts like a pull-out drawer so that the bag can be easily inserted at the bottom of the vessel and air then inflates it. It also has a magnetic stirrer in the bottom and so does not require an impeller shaft. This removes any need for the high ceilings that were traditionally needed to get an impeller shaft into the bioreactor.

‘Because there is no shaft, we can incorporate baffles into the bag. This breaks up any vortices to give quicker mixing,’ says Bulpin. ‘When carrying out a pH adjustment, If you don't have adequate mixing, the addition can be detrimental to the cells,’ he says.

An additional advantage is that the turn-down ratio is 5:1, so effectively the reactor vessel can operate at a fifth of total volume successfully, whereas many competitor products have a turn down ratio of 2:1.

The company has also introduced a different approach to sensing technology. ‘Whereas usually the sensors are located in the main chamber but with only a limited number of ports, ours are mounted on an extraneous loop which gives enormous sensing flexibility.’

This strategy of redesigning what has gone before extends to all parts of the process, but the industry has already seen a lot of change. ‘Years ago, when the first mAbs were produced you were getting about 200µg/L; today, with current processes on an industrial scale, up to 5g/L is now reasonable, so that is effectively a 25-fold increase in productivity in the bioreactor,’ says Bulpin. ‘This means that instead of needing a 15,000L stainless vessel, you can now get the same yields in a 1,000L–2,000L SU bioreactor.’

Latterly, in process development there was a distinct disconnect between what was done upstream and downstream

However, latterly, in process development there was a distinct disconnect between what was done upstream and downstream. ‘For the upstream guys, their basic efforts were to get the titre as high as possible. Traditionally, the upstream team would throw everything into getting the best titre they could and they would effectively end up with a thick “stew”, which they would then pass to the downstream guys.

‘Today we take a more holistic view over the whole process train and question whether getting the highest titre is the best option if you cannot purify it down stream. Basically, if what the upstream guys are producing is impossible to clarify downstream, it is not going to work, so it is all about getting the balance right between upstream titres and downstream clarification.

‘With these high titres process people have been working on new expression platforms – still CHO but different cell types, different varieties that can be used in animal origin-free media and more recently chemically defined media – so offering full traceability.’

Down stream, historically clarification and centrifugation have been in vogue, says Bulpin. ‘Now the sector is moving towards flocculation techniques where they are using smart polymers or pH changes to cause impurities or cell residues to precipitate and then to carry out clarification through filtration before they go on to chromatography. We are looking to develop and optimise devices that compress the processing template but in parallel we also do research into what the template could look like in the future.

‘Take the clarification steps: currently there are still a lot of people using centrifugation, which means hard stainless steel equipment. It is somewhat limited, so to turn that into a more continuous process you are looking at smart polymers and circulation technology that can achieve the same process but in a continuous and cyclical way – in the same way that people are looking at achieving continuous chromatography. At the bench scale it is doable, as the technology already exists,’ says Bulpin.

At the moment the company’s offering covers seven out of the 10 key bioprocess areas and it has been working hard to gain expertise in the remaining three – cell culture media being one of them.

At the moment the company’s offering covers seven out of the 10 key bioprocess areas and it has been working hard to gain expertise in the remaining three

In September 2014, Merck KGaA and Sigma-Aldrich agreed a deal in which Merck KGaA acquired Sigma-Aldrich for US$17bn – $140 cash per share. With the deal, Merck will gain access to the portfolio of SAFC, a supplier of cell culture and sera products to the biopharma industry. Another area of particular interest for the company is antibody drug conjugates (ADCs) and the deal would give Merck SAFC’s not insubstantial competency in ADCs. ‘ADCs are really hot area right now,’ states Bulpin, but whereas regular biologicals are produced in an aqueous milieu, ADC's require a solvent-water mix. This has implications for which SU films can be used and, in particular, the E&L profiles.

Another general biopharma challenge is virus removal. After the harvest and purification steps come dedicated steps to ensure virus inactivation or removal. ‘Instead of being reactive and looking to get the viruses out should they by chance have got in somewhere, we are looking at being proactive and assessing whether there are opportunities for viral filtration or clearance upstream, to prevent things getting in,’ Bulpin says. ‘For example, should we be filtering cell culture media? We already do sterile filtration before it goes in the bioreactor but could we carry out a tighter virus filtration?

‘Historically you could not do a virus filtration step upstream with media containing bovine derivatives because the bovine plasma would just clog the filter, and there are still a number of classical cell cultures that are difficult to filter due to clogging, but it is an area that we are working on, so watch this space,’ he says.