Nanoantibody Development Shows Momentum —Join the Dance Now Or Play Catch-up Forever

Oct 8, 2017, San Diego, CA: Last week, Belgian company Ablynx Inc. announced IPO plans based on robust results from a Phase III study with caplacizumab, the very first nanoantibody drug ready for market.

Caplacizumab targets von Willebrand factor (vWF), will benefit patients afflicted with acquired thrombotic thrombocytopenic purpura (aTTP), a life-threatening autoimmune blood clotting disorder.

The Phase III study (named as HERCULES) met the primary endpoint, namely a statistically significant reduction in time to platelet count response in patients, besides providing standard-of-care. Patients on caplacizumab were 1.5 times more likely to achieve platelet count response at any given time point, compared to placebo control. In addition, the study also met two key secondary endpoints, namely, a 74% reduction in the percentage of patients with recurrence of aTTP or related death, and absence of any major thromboembolic event during study. In addition, the proportion of patients with a recurrence of aTTP during the study period (including the 28 day follow-up period after discontinuation of the drug) was 67% lower in the caplacizumab arm compared to the placebo arm, demonstrating the sustained benefits from the treatment.

Ablynx immediately sought to capitalize the outstanding clinical benefits provided by caplacizumab. On the same day of publicizing their clinical trial results, Ablynx announced filing of a Registration Statement on Form F-1 with the U.S. Securities and Exchange Commission for a proposed stock offering (IPO in the US in the form of American Depositary Shares (“ADSs”) and private placement of ordinary shares in Europe). Ablynx plans to obtain $150 million to finance its commercialization of their new nanoantibody in the U.S. and Europe. With the new developments, the company also expects to accelerate the clinical development of other nanoantibodies, including ALX-0171 which targets respiratory syncytial virus (RSV) infection.

With these exciting news out on the market, now is a great time for the traditional players in the pharmaceutical industry to take a good look and seriously evaluate the possibility to add nanoantibody to their development portfolio. The time is now because success of the new Ablynx drug has minimized the investment risk by proving the feasibility, potential, and advantages of nanoantibodies. The time is now because the field of therapeutic nanoantibodies is still wide open, unlike other crowded, highly competitive arena of conventional antibodies. The time is now, also because with nanoantibodies just starting to get onto the map, an investment in nanoantibodies has the potential of delivering extraordinary returns.

Allele is actively involved in the preclinical development of therapeutic nanoantibody for the past several years, and has accumulated significant IP and technological know-how in this space, and a dozen or so programs ranging from oncology to inflammation. We have a high-speed new technology by which we can get dozens of new nanoantibodies per year, and a pipeline by which we routinely perform humanization, bi- or multi-valency, and expression optimization. We welcome inquiries into our development program, collaboration or joint development proposals, and in exploring investment opportunities with us.

Contact Alleleblog or the Allele nAb team: Dr. Jenny Higginbotham, jhigginbotham@allelebiotech.com; Dr. Nobuki Nakanishi, nnakanishi@allelebiotech.com

Tags: bivalent, llama antibody, mAb, multivalent, nAb, nanoantibodies, nanoantibody, nanobodies, nanobody, single domain antibody, VHH

Researchers use GFP nano antibody to study organ growth

Single-domain nano antibodies have a broad range of applications in biochemistry due to their small size, high affinity, and high specificity. Now, a team of researchers from the University of Basel and the University of Zurich has demonstrated that nano antibodies can be used for research in complex living organisms such as Drosophila, uncovering another new and exciting application for nano antibodies.

The team used nano antibodies to develop an assay for studying morphogens, molecules that regulate the pattern of tissue growth and the positions of various cell types within tissue. Morphogens form long-range concentration gradients from a localized source, ultimately determining the fate and arrangement of cells that respond to that gradient. Drosophila is a classic model system for understanding how morphogens regulate organ development. One morphogen called Dpp controls uniform proliferation and growth of the wing imaginal disc. Yet because Dpp is an extracellular, diffusible protein, it is difficult to immobilize in situ. Therefore, despite over 20 years of studying the role of Dpp as a morphogen, the lack of a dynamic system for controlling Dpp gradients has prevented researchers from understanding precisely how Dpp governs development of the wing disc.

By developing a novel synthetic system using nano antibodies, the researchers were able to modulate the concentration gradient of Dpp at the protein level. Their system—coined “morphotrap”—uses a membrane-bound GFP nano antibody to “trap” GFP-tagged Dpp at different locations along the wing imaginal disc. By tethering Dpp in a controlled spatial manner, researchers were able to determine how Dpp gradients affect wing disc development. They discovered that the gradient of Dpp is required for the patterning of the wing disc but not for lateral growth, disproving one of the field’s popular theories that address the role of Dpp. In addition to resolving the controversy with respect to the role of Dpp as a morphogen, this study pioneers a new method for using nano antibodies in situ.

“Dpp spreading is required for medial but not for lateral wing disc growth.”
Harmansa S., Hamaratoglu F., Affolter M., Caussinus E.
Nature. 2015 Nov 19;527(7578):317-22. doi: 10.1038/nature15712. Epub 2015 Nov 9.

Tags: Allele Biotech, anti-GFP, camelid antibodies, Fluorescent proteins, morphogens, nanobodies, VHH

Lab Skills You Stopped Being Proud Of

Molecular biologists who were in graduate school in the 90’s learned how to isolate plasmid DNA from E. coli cultures by a method called “boil-prep” during their first lab rotation. This process involved mixing the bacterial cell pellet in a little bit of detergent, salt and sucrose, dabbed with some fresh lysozyme, and then you are ready to cook, literally! Bacterial cell membranes are disrupted by boiling this soup in a beaker of water over a Bunsen Burner for one minute, and the debris (containing the broken cell membrane and attached chromosomal DNA) is collected by centrifugation in a microfuge at top speed for 10 minutes. Then comes the step that differentiates a true master of lab skills versus a rotation student—if you knew just the right amount of bacterial culture to begin with and handled the E coli pellet by the right techniques, a skillful lab person could collect nearly all the liquid without disturbing the pellet. Pouring out the plasmid-containing supernatant without dislodging the goo on the side/bottom of the tube was such a desirable skill that would not only give you your plasmid but also give you admiration from fellow lab members. That is, of course, if you were doing it before the mid-90’s, because after the introduction of miniprep spin columns by Qiagen, nobody, even the true masters of boil-preps (or its contemporary alkali prep that also involves pelleting by centrifugation and careful removal of tiny volume of liquids surrounding small pellets) would be showing off those skills any longer.

It is actually never easy or fun to collect liquid surrounding small amount of beads or pellets as you always have to struggle to remove as much liquid as possible while trying not to lose any of the beads

Some of the old-timers used to also be very proud of being able to pour a “sequencing gel” (a very thin ~40 cm x 30 cm polyacrylamide gel). I still remember the first time I reported to the second rotation lab at USC. After describing the lab research, the PI showed me around the lab and complained how “Sarah destroyed all my sequencing gel plates”. But consider this, in order to avoid any greasy spot on either plate, you needed to wash both of them fanatically if not religiously. Why? You would have just about a minute’s time to pour non-polymerized acrylamide without leaking from the sides or bubbles forming anywhere in the DNA running lanes, and then inserting a pair of paper-thin combs, all at a speed quicker than TEMED/AP-catalyzed acrylamide polymerization. Good thing that after capillary sequencing was invented, we all happily retired our sequencing-gel pouring skills with a collective sigh of relief.

Technology will always move forward, so will the skills lab researchers will be required to perfect. Using a spin column is very much a “skill-less” technique in contrast to collecting pellets and washing beads after centrifugation, but when there is a choice, people will chose the method that requires “less skills”, such as the spin-column format as the preferred platform for the new FP-nAb™ products.

BTW, like to have information on the spin column kit? Here it is: http://www.allelebiotech.com/gfp-nab-agarose-spin-kit-20-reactions/

Tags: agarose beads, camelid antibody, capture reagent, co-IP 101, GFP, gfp affinity tag, gfp antibody, GFP co-IP, GFP-nAb, magnetic beads, mNeonGreen-nAb, nano antibodies, nanobodies, polyacrylamide beads, RFP, spin column, Trap, VHH domain

When Great is not Good Enough—VHH Antibodies Engineered for 10 Fold Affinity Increase

Single Domain antibodies (VHH fragments, nanobodies, or as we call them, nAbs) have been generated by injecting llamas with ligand-bound GPCR for the purpose of obtaining crystals of active-state structures. Such structural information could be critical in understanding drug functions and screening for new drugs. The unique ability of VHH fragments to fit into protein-protein complex crevices and hold proteins together was demonstrated by two Nature publications from Brian Kobilka’s group at Stanford ([1, 2], also see Allele Newsletter of Sep 4th, 2013). The nano antibody used in those studies, Nb80, showed affinity towards only the active state of the target GPCR.

However, even with an antibody as great as Nb80, the authors were only able to co-crystal GPCR beta2-adrenoceptor (b2AR) with high affinity agonists, not its natural agonists such as adrenaline. In yet another Nature paper published just now, the Kobilka lab showed that Nb80 could be further improved by 10 times in affinity, through in vitro evolution [3]. They presented Nb80 on the surface of yeast using an existing yeast display system, then applied standard limited mutagenesis and magnetic separation technologies for screening. After about 5 rounds of selection, a new version of VHH Nb6B9 was isolated that bound to ligand-loaded GPCR with a kD of 6.4 nM. For the first time, a co-crystal of b2AR-adrenoline was made.

Rasmussen et al. Nature, 2011 Structure of a nanobody-stabilized active state of the b2 adrenoceptor
Rasmussen et al. Nature, 2011 Crystal structure of the b2 adrenergic receptor–Gs protein complex
Ring et al. Nature, 2013 Adrenaline-activated structure of b2-adrenoceptor stabilized by an engineered nanobody

Update here http://www.allelebiotech.com/nab

Tags: alpaca antibodies, camelid, Co-IP, GFP as tag, GFP fusion, GFP-Trap, nAb, nAbs, nanobodies, nanobody, nanobody 101, pull down, RFP-Trap, single domain antibodies, VHH, VHH antibodies

Visualizing Endogenous Synaptic Proteins in Living Neurons

The recently published method is based on the generation of disulfide-free “intrabodies”, a structure from the 10th fibronectin type III domain known as FingRs. These affinity molecules were fused to GFP for direct fluorescence miscroscopy. The FingRs do not need di-sulfite bonds and are therefore better folders in mammalian cells. Specifically, a library was screened with in vitro display to identify FingRs that bind two synaptic proteins, Gephyrin and PSD95. After the initial selection, the researchers from USC secondarily screened binders using a cellular localization assay to identify potential FingRs that bind at high affinity in an intracellular environment. As it turned out, only 10-20% of the original positive clones bind well inside the cells, suggesting this type of further screening was a critical step.

The expression of intrabody is transcriptionally regulated by the target protein through a ZFN-repressor fusion. This transcriptional control system matches the expression of the intrabody to that of the target protein regardless of the target’s expression level. This design virtually eliminates unbound FingR, resulting in very low background that allows unobstructed visualization of the target proteins. As result, the FingRs presented in this study enabled live cell visualization of excitatory and inhibitory synapses, and apparently without affecting neuronal function.

Technically, the reason to use in vitro mRNA display was required by the need to use a large library (>10exp12, beyond the limit of the more commonly used phase display) to find good binders. A similar visualization system can be established using more potent affinity domains such as the VHH single-domain antibodies that have only one, sometimes dispensable, di-sulfite bond. The VHH domain nanobodies can be more easily isolated from camelid animals. Another improvement to the visualization system can be made by using stronger, superresolution-ready FPs such as mNeonGreen or mMaple to enable single molecule imaging, which is particularly interesting for studying synapses and applied to the BRAIN initiative.

Gross et al. Neuron, June 2013, http://www.ncbi.nlm.nih.gov/pubmed/23791193

Tags: alpaca antibodies, BRAIN, FingR, fluorescent protein tag, intrabodies, mNeonGreen, nAb, nanobodies, neuron, single domain, Synapses, VHH, VHH antibodies