Biosimilars: They May Look the Same, but One is a Real Stinker

Biosimilars by nature look much like their comparator products, but they sometimes behave quite differently. That’s because the two products often originate from different cell lines or expression systems. And no matter how hard you strive for parity in the way they’re cultured, minor differences in manufacturing can lead to sticky variations in primary amino acid sequence, glycosylation chemical modifications and protein folding issues. The FDA understands biosimilar products sometimes behave differently than their name-brand counterparts. But, they do expect you to understand why those differences occur, and to demonstrate that they have no clinical significance. That’s where ABC Laboratories comes in.

Choosing the Right Analytical Partner May Be the Most Economically Important Decision You Make

FDA guidance calls for a “complete and thorough” CMC section that begins with extensive comparative characterization of the biosimilar and... click here for more.

Challenges in the Characterization of Antibody Drug Conjugates

By Glenn Petrie, Ph.D.
Senior Scientific Advisor
ABC Laboratories
www.abclabs.com

Antibody Drug Conjugates (ADC) provide a unique new treatment for a variety of cancers. ADCs consist of a monoclonal antibody (mAb) targeted to the receptor of interest and linked to a highly cytotoxic payload. The mAb binds to the cell and enters the cytoplasm. Once inside the cell, the linker is cleaved and the toxin released. This provides the ability to use highly cytotoxic compounds without the serious side effects of systematic chemotherapy. It is estimated that there are 100-150 ADCs currently in preclinical development. ADCs present unique analytical challenges.

In addition to the complicated mAb, there is the added complexity of combining a cleavable linker and a cytotoxic drug. This introduces the necessity for determining drug loading, linkage sites and Drug Antibody Ratio (DAR). The critical technique for analysis on ADCs is ultra-high resolution QToF mass spectroscopy. This allows for determination of relative loading, DAR and linkage sites, as well as PTMs, disulfide linkages and related substances/degradants (deamidation/oxidation, truncations, and amino acid substitutions). Due to their high resolution, UHR-QTof instruments have the ability to sequence proteins up to 25-30 kDa. The specific protease IdeS (which cleaves just below the hinge region of IgG) under reducing conditions results in three polypeptide chains of ~ 25kDa: Fd region, Fc/2 region and the LC region. Analysis of these digests by UHR QTof MS yields complete sequencing of each polypeptide, DAR, payload and glycan distribution. If necessary, other proteases may be utilized for more detailed analysis. Additional characterization includes the following:

• Intact mass
• Deglycosylated mass
• IEX
• Imaging CIEF
• CE-SDS
• SEC
• N-linked glycan analysis
• HIC (secondary DAR analysis)
• Binding assay
• Bioassay
• Higher Order Analysis (CD, AUC, DSC, etc.)

The FDA considers the mAb a drug substance so both the mAb and ADC must be fully characterized. In addition, the agency has been requesting characterization of charge variants of the mAb and ADC. This necessitates preparative IEX followed by characterization of the acidic and basic fractions. Based on all these considerations, characterization of ADCs require careful planning and attention to detail.

Download ABC's 3 Presentations from AAPS 2015

Below are recent presentations by ABC at this year's AAPS in October.

Don’t Leave Method Transfers to Chance

When planning your development strategy, you probably didn’t give much thought to method transfers. But when an analytical method doesn’t perform as expected, it can take precious days of investigative work to find the problem, and even more to resolve it. Learn about common pitfalls that cause method transfer failures, how to decide what type of method transfer makes sense for your study, and how to implement a fail-safe communication plan that will help put your outsourcing relationship on the right course.

To download this presentation, click here.

 

The Critical Role of CMC in your IND Submission

Early stage drug developers generally have their sights firmly set on the initiation of clinical trials, focusing on toxicological and pharmacological studies. Often, the importance of Chemistry, Manufacturing and Control (CMC) data is underestimated. But the CMC package is critical to IND approval, and meeting all FDA requirements demands careful planning and sound execution. This discussion will cover the risk/reward criteria for determining the level and degree of method validation, reference standard characterization and formulation; as well as potential pitfalls and ways to streamline the entire development process.

To download this presentation, click here.

Are Extractables & Leachables Going Phase-Appropriate?

Not long ago, it was more or less conventional wisdom that E&L studies should be performed late in the development cycle—even after the final container/closure system is known. But current regulatory trends suggest that, like many things GxP, expectations for early E&L data are on the rise. In recent years, many drug sponsors have been required to address E&L questions as early as phase I/II. It isn’t just CTM containers causing concern; questions often involve the equipment used in manufacturing and dosing devices. Phase-appropriate E&L program design can help you avoid related clinical holds and unplanned expense.

To download this presentation, click here.

Gene Editing - A New Frontier

By Glenn Petrie, Ph.D.
Senior Scientific Advisor
ABC Laboratories
www.abclabs.com

A new technology for “editing” genes has scientists excited about an entirely new method for treating disease. The CRISPR technique, along with other gene-editing technologies (TALENS, zinc finger nucleases) allow for the precise deletion of specific DNA sequences. CRISPR involve a Cas9 protein linked to an RNA strand. The RNA sequence serves to target the specific DNA sequence of interest and once bound the Cas9 enzyme cleaves both strands of the DNA.

Above graphic credit (link) to Scitechweb.com 

Since RNA synthesis is relatively cheap and easy this technology has exploded in the last 2 years. Feng Zhang and Eric Lander at MIT have created CRISPR libraries that target essentially the entire human genome. The promise of the technology is to delete genetic mutations and replace them with the correct genes.  Initial targets involve only a single mutation, e.g. sickle-cell anemia, progressing to diseases involving multiple mutations.

As with any new technology there are calls for caution. Chinese scientists reported attempts to repair defective genes in human embryos. This held up the specter of future “designer babies” enhanced in their embryonic stages. Others warn that this technology could be used to “weaponize” bacteria or viruses. Several prominent scientists have proposed a complete moratorium on gene editing until proper safeguards are in place.

Despite these concerns several biotech start-ups have been founded in the last 2 years including Intellia Therapeutics, Editas Medicine and Crispr Therapeutics. Successful in vitro results have been reported for the repair/modification of clinically important genes in hematopoietic stem cells, fibroblasts and T-cells. A quick internet search yields a number of companies offering their services to utilize CRISPR to perform gene editing in both cell lines and whole animals. Based on the extremely rapid advances in this area, gene-editing using CRISPR and other technologies promises to revolutionize our ability to manipulate the genome and attack genetic diseases.

A Biotech Scientist Answers the Question: "Is JURASSIC WORLD Possible?"

By Glenn Petrie, Ph.D.
Senior Scientific Advisor
ABC Laboratories
www.abclabs.com

As a boy I was fascinated with dinosaurs. But while most children grew out of this by 7 or 8, I remained engrossed in all things “saurus”. As I started my career in biotechnology, I was particularly interested in Michael Crichton’s book Jurassic Park. I read it in a single sitting and went to the first showing when the movie was released. Now that JURASSIC WORLD is a worldwide phenomenon, interest in reviving extinct species, or de-extinction, has been brought to the forefront. But could JURASSIC WORLD actually be possible? The short answer is no. DNA is the key to any attempts at de-extinction, but while stable, it is not stable for millions of years. Therefore, since dinosaurs went extinct 65 million years ago, there is no viable DNA

However, DNA can survive tens of thousands of years in the right environment, particularly frozen. There are numerous articles in both the scientific and popular literature regarding bringing Wooly Mammoths back to life. Frozen carcasses discovered in Russia have yielded partially intact DNA. JURASSIC WORLD scientists use the bottom-up technique, i.e. start with a fairly complete genome and plug the gaps with that of similar species. In reality the top-down approach is more likely since only partial DNA genomes have been recovered. Scientists are attempting to modify elephant DNA with some of the mammoth’s. The goal is to obtain a hybrid, an elephant with some mammoth traits. With the explosion in biotechnology, one could envision a Pleistocene Park. Rather than dinosaurs it would be populated with animals from the Pleistocene era, ~10,000 years ago. Among the possible exhibits could be Wooly Mammoths, Saber Tooth Cats, Wooly Rhinoceros, Giant Ground Sloths and the Giant Short-faced Bear. Think of the La Brea Tar Pits brought to life.

Even if this is possible, should it be attempted (“But John, if Pirates of the Caribbean breaks down, the pirates don’t eat the tourists.”)? While no one is seriously proposing de-extinction as a theme park, many are interested in using this technology to increase biodiversity and bring back species that humans destroyed, e.g. passenger pigeon, Steller seal, Tasmanian tiger and the dodo. Since there are numerous specimens of these species throughout the museums of the world, there is a reasonable chance of success. However, many ecologists see this as a zero sum game. They believe that any money spent on de-extinction represents less money for efforts to save endangered species; protection, habitat, etc. There may be a middle ground in which de-extinction methods could be used with endangered species to increase genomic diversity and increase the chances for a healthy population.

I look forward to following the latest developments in this exciting field and will provide an update with the release of JURASSIC WORLD 2.

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