Enumeral Explained

Enumeral Biomedical Holdings, Inc.
Type:	Public
Fate:	Assets sold to Xoma Corporation during bankruptcy
Hq Location Country:	United States
Industry:	Biotechnology
Products:	Monoclonal antibodies targeting immune checkpoint proteins
Num Employees:	10 (2017)

Enumeral was a Cambridge, Massachusetts-based biotechnology company which developed monoclonal antibody immunotherapies through an 'immunoprofiling' platform that allowed it to scan the human immune microenvironment and identify and validate potential drug candidates. The company filed for Chapter 11 bankruptcy and arranged to sell its assets to Xoma Corporation in January 2018.

The company

Enumeral was founded in 2009 to bring together various immunoprofiling technologies from Harvard University, Massachusetts Institute of Technology, the Whitehead Institute for Biomedical Research and Massachusetts General Hospital.^[1] The company's Scientific Founder was Christopher Love, Associate Professor of Chemical Engineering at MIT;^[2] the Executive Chairman is John Rydzewskand and its CEO is Arthur Tinkelenberg. In 2014 the company was taken public through a reverse takeover into a shell called Cerulean Group. Its stock is traded OTC in the US, with trading in the OTCQB marketplace tier commencing on 4 August 2014.^[3] The stock code is ENUM.

By 2015, Enumeral had completed pre-clinical development of PD-1 inhibitors and sought partners to enter clinical development with.^[4] In December 2016, Enumeral completed raising to fund long-term development plans, but by May 2017, the company announced it only had sufficient cash on hand to fund operations through June 2017.^{[5] [6]} Shortly thereafter, in June, the company dismissed its R&D research staff.^[7] In August 2017, Enumeral was kicked out of its headquarters in Cambridge due to non-payment of rent and other fees.^[8] The Cambridge headquarters was also the home of Celgene and Unum Therapeutics. By the time the company lost its headquarters, Arthur Tinkelenberg was being described as the company's "former president and chief executive officer". In January 2018, Enumeral struck a deal with Xoma Corporation, located in the San Francisco Bay Area, to sell its assets for, while concurrently filing for Chapter 11 bankruptcy.^{[9] [10]}

Platform

Enumeral's platform consists of various proprietary cellular libraries derived from target-specific immunized sources or from human patient donors. The platform has three main parts:

• Microengraving. This platform has its origins in work which Love et al. published in the journal Nature Biotechnology in 2006. Their foundational paper showed that it was possible to quickly capture a large mass of antibody-producing cells through engraved microarrays based on intaglio printing, where those arrays were carrying the secreted products of single cells.^[11] The Love group elaborated on the utility of this microengraving technology in 2008 in two key papers. In the first they applied it to PBMCs from a Type I diabetic patient and reported that a small percentage of CD19+ B cells were secreting proinsulin-reactive antibodies.^[12] In the second they showed how the technology could be used to describe the different kinds of antibodies produced during a multipart vaccination.^[13] In 2010 the Love lab demonstrated that its microengraving technology could be used to quantify the rates of secretion of up to four cytokines simultaneously released from individual viable primary immune cells, and that, among other things, primary T cells with specific profiles of secretion could be recovered and expanded in vitro.^[14] In 2011 the Love lab provided proof that microengraving would allow multiple fresh CD8+ T cells to be evaluated for their cytotoxic activity and cytokine secretion.^[15] A 2013 paper from the Love lab reported the use of microengraving in evaluating the expression of pro-angiogenic ELR+ CXC chemokines by colorectal tumor and stromal cells.^[16] The Love lab published a review on various single-cell technologies for monitoring immune systems, including the microengraving approach, in Nature Immunology in 2014.^[17]
• Checkpoint discovery. This technology allows new immune checkpoints in T cells to be discovered. It does so through the identification of small hairpin RNA molecules involved in the release of blocks on T-cell proliferation at the time of tumour antigen recognition. This technology was discovered in the laboratory of Dr Kai Wucherpfennig at the Dana–Farber Cancer Institute and was published in Nature in 2014.^[18] Kai Wucherpfennig currently serves on Enumeral's Scientific Advisory Board.^[19]
• Whole-exome sequencing. This technology, first unveiled in Nature Biotechnology in 2014, involves the sequencing of whole exomes of circulating tumor cells by means of cell enrichment and isolation, genomic amplification, library qualification and 'census-based' sequencing.^[20]

Anti PD-1 antibodies

An early commercial interest of Enumeral has focused on PD-1, currently targeted by two FDA-approved monoclonal antibody drugs - Keytruda, from Merck & Co., and Opdivo, from Bristol-Myers Squibb. In 2015 Enumeral reported that it had used its platform to raise anti-PD-1 antibodies that did not compete with Keytruda or Opdivo for binding to PD-1, nor did they appear to compete with PD-1's ligand, PD-L1. These potentially allosteric antibodies also produced more interferon gamma and showed dose-dependent increases in T cell CD25 expression.^[21] Further, Enumeral's antibodies caused higher T cell activation in ex vivo human assays than the currently marketed anti-PD-1 antibodies^[22] and, in that same setting, in combination with one of the marketed antibodies, could elicit an additive effect on T cell activation.^[23] Enumeral expects to take an anti-PD-1 antibody into clinical testing in 2016.^[24]

Merck collaboration

In December 2014 Enumeral announced a collaboration with Merck & Co. in which the two companies would use the Enumeral platform to interrogate the tumor microenvironment in colorectal cancer tissues obtained directly from patients, with the aim of identifying functional cellular responses to Merck-developed immuno-oncology products.^[25] In September 2015 Enumeral announced that the Merck collaboration had achieved its first milestone, enabling Enumeral to receive a milestone payment from Merck.^[26]

Notes and References

1. Web site: 10-Q: Enumeral Biomedical Holdings Inc. Marketwatch.com. 28 December 2015.
2. Web site: 4 August 2014 . Enumeral Biomedical Raises $21.5 Million from New and Current Investors, Begins Public Trading . 2023-12-07 . www.sec.gov.
3. Enumeral Biomedical Raises $21.5 Million from New and Current Investors, Begins Public Trading. August 4, 2014. December 27, 2015. https://web.archive.org/web/20150322141209/http://www.enumeral.com/news-events/pr-2014-08-04.php. March 22, 2015. Enumeral.
4. News: Cambridge Biotech Enumeral Biomedical Has Cash to Fund Its Operations Only Into Next Month. Keown. Alex. May 30, 2017. July 20, 2018. BioSpace.
5. News: Cambridge biotech Enumeral faces uncertain future as cash dries up. Stendahl. Max. May 26, 2017. Boston Business Journal. July 20, 2018.
6. Web site: 26 June 2017 . Enumeral Biomedical believes it has sufficient cash to continue to explore strategic alternatives only into July 2017 . 7 December 2023 . Reuters.
7. News: Faltering Enumeral Biomedical Cuts R&D Staff, Alters Executive Compensation Deal. Terry. Mark. June 20, 2017. July 20, 2018. BioSpace.
8. News: Enumeral Biomedical Gets Evicted as it Winds Down Operations. Terry. Mark. August 29, 2017. July 20, 2018. BioSpace.
9. News: Cambridge's Enumeral Filed for Bankruptcy, Sells Assets to Bay Area's XOMA. Keown. Alex. February 7, 2018. July 21, 2018. BioSpace.
10. Form 8-K: Enumeral Biomedical Holdings, Inc.. January 26, 2018. U.S. Securities and Exchange Commission. July 20, 2018.
11. Love JC . Ronan JL . Grotenbreg GM . van der Veen AG . Ploegh HL . A microengraving method for rapid selection of single cells producing antigen-specific antibodies . Nat. Biotechnol. . 24 . 6 . 703–7 . June 1, 2006 . 10.1038/nbt1210 . 16699501. 2369641 .
12. Bradshaw EM . Kent SC . Tripuraneni V . Orban T . Ploegh HL . Hafler DA . Love JC . Concurrent detection of secreted products from human lymphocytes by microengraving: cytokines and antigen-reactive antibodies . Clin Immunol. . 129 . 1 . 10–18 . October 1, 2008 . 18675591 . 10.1016/j.clim.2008.06.009 . 2577144.
13. Story CM . Papa E . Hu CC . Ronan JL . Herlihy K . Ploegh HL . Love JC. . Profiling antibody responses by multiparametric analysis of primary B cells . Proc Natl Acad Sci U S A . 105 . 46 . 17902–7 . November 18, 2008 . 19004776 . 10.1073/pnas.0805470105 . 2584674. 2008PNAS..10517902S . free .
14. Han Q . Bradshaw EM . Nilsson B . Hafler DA . Love JC . Multidimensional analysis of the frequencies and rates of cytokine secretion from single cells by quantitative microengraving . Lab Chip . 10 . 11 . 1391–1400 . June 7, 2010 . 20376398 . 10.1039/b926849a . 3128808.
15. Varadarajan N . Julg B . Yamanaka YJ . Chen H . Ogunniyi AO . McAndrew E . Porter LC . Piechocka-Trocha A . Hill BJ . Douek DC . Pereyra F . Walker BD . Love JC . A high-throughput single-cell analysis of human CD8⁺ T cell functions reveals discordance for cytokine secretion and cytolysis . J Clin Invest . 121 . 11 . 4322–31 . November 1, 2011 . 21965332 . 10.1172/JCI58653 . 3204845.
16. Adalsteinsson VA . Tahirova N . Tallapragada N . Yao X . Campion L . Angelini A . Douce TB . Huang C . Bowman B . Williamson CA . Kwon DS . Wittrup KD . Love JC . Single cells from human primary colorectal tumors exhibit polyfunctional heterogeneity in secretions of ELR+ CXC chemokines. . Integrative Biology . 5 . 10 . 1272–81 . October 5, 2013 . 23995780 . 10.1039/c3ib40059j . 4034677.
17. Chattopadhyay PK . Gierahn TM . Roederer M . Love JC . Single-cell technologies for monitoring immune systems . Nat Immunol . 15 . 2 . 128–35 . February 1, 2014 . 24448570 . 10.1038/ni.2796 . 4040085.
18. Zhou P . Shaffer DR . Alvarez Arias DA . Nakazaki Y . Pos W . Torres AJ . Cremasco V . Dougan SK . Cowley GS . Elpek K . Brogdon J . Lamb J . Turley SJ . Ploegh HL . Root DE . Love JC . Dranoff G . Hacohen N . Cantor H . Wucherpfennig KW . In vivo discovery of immunotherapy targets in the tumour microenvironment. . Nature . 506 . 7486 . 52–7 . February 6, 2014 . 24476824 . 10.1038/nature12988 . 4052214. 2014Natur.506...52Z .
19. Web site: Enumeral Scientific Advisory Board. Enumeral.com. https://web.archive.org/web/20160105122128/http://www.enumeral.com/about-us/advisors.php. January 5, 2016. 28 December 2015.
20. Lohr JG . Adalsteinsson VA . Cibulskis K . Choudhury AD . Rosenberg M . Cruz-Gordillo P . Francis JM . Zhang CZ . Shalek AK . Satija R . Trombetta JJ . Lu D . Tallapragada N . Tahirova N . Kim S . Blumenstiel B . Sougnez C . Lowe A . Wong B . Auclair D . Van Allen EM . Nakabayashi M . Lis RT . Lee GS . Li T . Chabot MS . Ly A . Taplin ME . Clancy TE . Loda M . Regev A . Meyerson M . Hahn WC . Kantoff PW . Golub TR . Getz G . Boehm JS . Love JC. . Whole-exome sequencing of circulating tumor cells provides a window into metastatic prostate cancer. . Nat. Biotechnol. . 32 . 5 . 479–84 . May 1, 2014 . 24752078 . 10.1038/nbt.2892 . 4034575.
21. Enumeral Announces Identification of Anti-PD-1 Antibodies with Potential for Differentiated Mechanism of Action. September 24, 2015. Enumeral. December 28, 2015. https://web.archive.org/web/20160105104109/http://www.enumeral.com/news-events/news-events-press-release-2015-09-24.php. January 5, 2016.
22. Enumeral Reports That Its Novel Class of Anti-PD-1 Antibodies Elicits Higher T Cell Activation in Ex Vivo Human Assays than Currently Marketed Anti-PD-1 Antibodies. November 3, 2015. Enumeral. 28 December 2015. https://web.archive.org/web/20160105111315/http://www.enumeral.com/news-events/news-events-press-release-2015-11-03.php. January 5, 2016.
23. Enumeral Reports That Its Novel Class of Potentially Allosteric Anti-PD-1 Antibodies Can Elicit an Additive Effect on T Cell Activation in Ex Vivo Human Assays When Used in Combination With A Currently Marketed Anti-PD-1 Antibody. 27 December 2015. Enumeral. November 18, 2015 . https://web.archive.org/web/20160105040218/http://www.enumeral.com/news-events/news-events-press-release-2015-11-18.php . January 5, 2016 .
24. Enumeral Expands Scientific Advisory Board to Support Development of Novel Immunomodulators. 28 December 2015. Enumeral.com. June 4, 2015 . https://web.archive.org/web/20160105111857/http://www.enumeral.com/news-events/news-events-press-release-2015-06-04.php . January 5, 2016 .
25. Enumeral and Merck Form Collaboration for Predicting Clinical Drug Response with Human-driven Immune Profiling Platform. 27 December 2015. Enumeral.com. December 18, 2014 . https://web.archive.org/web/20160105035253/http://www.enumeral.com/news-events/pr-2014-12-18.php . January 5, 2016 .
26. Enumeral Achieves First Milestone in Merck Collaboration. 28 December 2015. Enumeral.com. September 8, 2015 . https://web.archive.org/web/20160105121906/http://www.enumeral.com/news-events/news-events-press-release-2015-09-08.php . January 5, 2016 .