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Roche’s GA101 (obinutuzumab): Engineering an antibody to beat Rituxan

The following is a guest post from Sally Church (known to many in the twittersphere as @MaverickNY), from the Pharma Strategy Blog.

Survival rates for people with B-cell driven blood cancers, such as non-Hodgkin’s Lymphoma and chronic lymphocytic leukemia, have vastly improved in the last decade thanks to the introduction of Rituxan, marketed by Biogen Idec and Genentech. But the drug, a chimeric monoclonal antibody targeting CD-20, a protein that sits on the surface of B-cells, has its limitations: not all patients respond at first, and others become resistant to the drug over time.

As a result, companies are tinkering with the sugar molecules that decorate antibodies in hopes of coming up with a drug that binds better to its target and, ultimately, is more effective at battling cancer. At the American Society of Clinical Oncology annual meeting, held earlier this year in Chicago, Roche offered Phase III data showing its glycoengineered antibody GA-101 worked better than Rituxan at delaying the progression of CLL. If all goes well with FDA, the drug could be approved by the end of the year.

BACKGROUND:

Although the CD20 antigen is expressed on both normal and malignant cells, it has proven to be a useful target therapeutically.  Rituximab, ofatumumab and most of the anti-CD20 antibodies in earlier development are Type I monoclonal antibodies, which means that they have good complement-dependent cytotoxicity (CDC) and Ab-dependent cell mediated cytotoxicity (ADCC), but are weak inducers of direct cell death.

In contrast to Type I monoclonal antibodies, next generation monoclonals are increasingly Type II, such as GA101 (obinutuzumab) in CLL and NHL and mogamulizumab (anti-CCR4), for T-cell leukemias and lymphomas.  They have little CDC activity, but are much more effective at inducing ADCC and also direct cell death, at least based on in vitro studies performed to date.

How does glycoengineering make a difference?

Glycoengineering is the term used to refer to manipulation of sugar molecules to improve the binding of monoclonal antibodies with immune effector cells, thereby increasing ADCC.

Obinutuzumab is a very different molecule from rituximab, in that it is a novel compound in its own right (originally developed by scientists at Glycart before being bought by Genentech).  It is not a biosimilar of rituximab.  It is also a glycoengineered molecule designed specifically to improve efficacy through greater affinity to the Fc receptor, thereby increasing ADCC activity.GA101

The overall intent with the development of obinutuzumab was to significantly improve efficacy over rituximab and Type I monoclonal antibodies in B-cell malignancies using glycoengineering techniques.

At the recent ASCO annual meeting, data from a phase III trial was presented to evaluate rituximab or obinutuzumab in combination with the chemotherapy chlorambucil versus chlorambucil alone in newly diagnosed CLL.  Patients elderly and had co-existing co-morbidities, excluding them from standard chemotherapy with fludarabine and cyclophosphamide (FC).

This two part trial sought to compare both combinations to the chemotherapy initially, and then against each other in a head-to-head comparison once the survival data matured in the second phase.  Data from the first phase of the study was reported at this meeting.

What did the results show?

When looking at the response rates, both obinutuzumab and rituximab combinations had a higher overall response rate (ORR) than chemotherapy alone (75.5% and 65.9% vs. 30.2% and 30.0%).  Importantly, the combinations had a great proportion of complete responses (CR) i.e. 22.2% and 8.3% compared to 0% in the chlorambucil arms.

Minimal residual disease (MRD), a measure of the number of leukemia cells remaining in the blood, was 31.1% in the peripheral blood of the obinutuzumab combination compared with 0% in the chemotherapy arm.  Corresponding values in the rituximab and chlorambucil arms were 2.0% and 0%, respectively.

Median progression-free survival (PFS) i.e. the length of time during which people lived without their disease worsening for the obinutuzumab plus chlorambucil arm were impressively higher than chemotherapy alone.  PFS was more than doubled (23 months compared to 10.9 months, HR=0.14, p <.0001) when compared to chlorambucil alone.  The corresponding outcome data for the rituximab combination were 15.7 versus 10.8 months for chlorambucil alone (HR=0.32, p <.0001).

Since ASCO, Roche have announced that the FDA granted Priority Review for obinutuzumab in CLL (in addition to the Breakthrough Designation already received in May, when the company filed a new drug application for obinutuzumab), meaning that the PDUFA date is set as December 20th.  In addition, the Data Monitoring Committee decided that the interim data analysis was sufficient to meet the primary endpoint of the trial, ahead of schedule.  The data confirms that obinutuzumab was superior to rituximab in terms of the disease worsening (PFS).  The full data will be presented at ASH in December, when overall survival data (ie did the patients live longer) may be available.

The adverse event profiles were slightly different between the monoclonal antibodies.  Patients in the obinutuzumab arm experienced more infusion site reactions, and a slightly higher degree of myelosuppression (thrombocytopenia and neutropenia), but lower infection rates.

Overall findings

The study demonstrated that both obinutuzumab and rituximab were more beneficial to elderly patients living with CLL and co-existing medical conditions than chemotherapy alone.  The final head to head analysis of the two combinations will be available once the second stage of the study has mature data.  Based on the progress to date, the signs are very encouraging that the chemical engineering behind the development of obinutuzumab may potentially have produced a superior compound to rituximab for treatment of B-cell malignancies.

Should the mature outcome data show a positive survival advantage in obinutuzumab’s favour over rituximab, we may well see similar glycoengineering techniques applied to other monoclonal antibodies in the near future, potentially leading to further improvement in outcomes.

 

New Targets in Advanced Prostate Cancer

The following is a guest post from Sally Church (known to many in the twittersphere as @MaverickNY), from the Pharma Strategy Blog.

Much hullabaloo has been in the medical news over the past year over new options for the treatment of metastatic castrate resistant prostate cancer (CRPC). FDA approval for two new drugs, abiraterone acetate (J&J’s Zytiga) and enzalutamide (Astellas/Medivation’s Xtandi), has meant a sharp focus on drugs that target the androgen receptor. But at the the American Society of Clinical Oncology Genitourinary (ASCO GU) symposium, held last month in Orlando, intriguing data on new targets for CRPC emerged.

Zytiga and Xtandi target the androgen receptor (AR) in very different ways, but the overall effect is similar, in that they can effectively reduce the levels of prostatic serum antigen (PSA), which is reactivated in tumors with advanced disease. Zytiga acts high up in the steroidogenic pathway and one side effect associated with monotherapy is the development of mineralcorticosteroid effects, leading to over stimulation of the adrenal glands and hypokalaemia.  This toxicity must therefore managed with concomitant prednisone therapy. Xtandi, meanwhile, more directly targets the androgen receptor, which tends to be amplified in advanced prostate cancer. The drug doesn’t have same effect on cortisol production as Zytiga, and can therefore be taken without steroids.

The androgen receptor isn’t the only valid target in CRPC, however.  Aldo-keto reductase 1C3 (AK1C3), an enzyme that can facilitate androstenedione conversion to testosterone, is also over-expressed in advanced prostate cancer. Several new agents in early development appear to specifically target AK1C3. At ASCO GU, a couple of abstract particularly caught my eye and are worth highlighting here:

1) Bertrand Tombal et al., presented the initial data on Xtandi monotherapy in advanced prostate cancer in the hormone-naive setting, that is prior to CRPC.  Traditionally, Androgen Deprivation Therapy (ADT) is given to patients with high risk disease.  In the US, LHRH antagonists are used first-line, followed by AR antagonists such as bicalutamide, giving a basis for the rationale testing Xtandi, which is a more complete antagonist of the AR than bicalutamide.

In this trial, the single arm design sought to determine whether not enzalutamide would have activity in patients who had not received standard ADT therapy. The waterfall plots in this study (n=67) were impressive. The results showed that:

a) Ninety-three percent of study participants experienced a ≥80% PSA decrease at week 25.

b) Median change in PSA was -99.6% (range -100% to -86.5%).

In other words, most of the men in this trial responded well to Xtandi, suggesting that a randomized trial is well worth pursuing next.

You can read more about the specifics of this new development and what Dr Tombal had to say here.

2) Ramesh Narayanan et al., presented an intriguing poster on a new preclinical compound from GTX Inc that specifically targets AK1C3. The results demonstrated some nice inhibitory activity of AKR1C3, with reduced androgen signaling and CRPC tumour growth. It is important to selectively inhibit C3 and not the C1 and C2 isoforms, since the latter are involved in production of the sex hormones.  Inhibition of C1 and C2 is also counter-productive because it can increase the androgenic signal and deprive ERβ of its ligand. To date, the challenge has been to develop a C3 isoform specific inhibitor, making GTX-560 a compound that may be worthwhile watching out for in the clinic.

Recently, Adeniji et al., (2011) observed that, “AKR1C3 plays a pivotal role in prostate tumor androgen biosynthesis, inhibitors of this enzyme have the potential to be superior to abiraterone acetate, a CYP17/20 hydroxylase/lyase inhibitor.”

Clearly, this is a promising development in CRPC, however, it is early days yet and we will have to wait and see how the clinical trials progress with this new agent.

New Developments in Advanced Pancreatic Cancer from ASCO GI 2013 – Part 1

The following is a guest post from Sally Church (known to many in the twittersphere as @MaverickNY), from the Pharma Strategy Blog.

The cancer research conference season kicked off in earnest in 2013 with the American Society of Clinical Oncology (ASCO)’s Gastrointestinal Symposium, held in San Francisco in late January. Some of the most anticipated data to be presented at ASCO GI was for drugs that treat pancreatic cancer, with three drugs—Celgene’s Abraxane, AB Science’s masitinib, and Sanofi’s S1, generating the most interest.

With this post, we’ll take a closer look at the most advanced of the three agents, Abraxane, which generated encouraging results in a Phase III study. Later this week, we’ll tackle masitinib and S1.

Abraxane is a nanoparticle albumin-bound form of the breast cancer drug paclitaxel, and is designed to improve the activity of the active ingredient. Abraxane is already approved in the US for advanced breast and lung cancers, and recently showed signs of activity in metastatic melanoma.

At ASCO GI, Daniel Von Hoff, director of the Translational Genomics Research Institute, presented data from a randomized phase III study called MPACT that compared the effects of Lilly’s Gemzar, the current standard of care, to a once weekly combination of Gemzar and Abraxane in patients with metastatic adenocarcinoma of the pancreas. With 861 patients, this was a large global study that sought to determine whether the combination would outdo the regulatory standard of care.

A note on the trial design: Although this study uses Gemzar as the standard of care, in practice, many leading oncologists prescribe FOLFIRINOX (fluorouracil, leucovorin, irinotecan and oxaliplatin) for advanced pancreatic patients. But because FOLFIRINOX is generic, and is not formally approved by FDA for advanced pancreatic cancer, Phase III studies tend to match new drug candidates up against Gemzar.

As Hedy Kindler, director of gastrointestinal oncology at the University of Chicago, explained, FOLFIRINOX is widely used because the regimen has “the higher response rate, and that has the longer median survival.”

However, FOLFIRINOX also has unpleasant side effects, and in private practice settings, oncologists prefer to use less toxic combinations based on Gemzar—namely, Gemzar alone, GemOx (with oxaliplatin), or GemErlotinib (with Tarceva, an EGFR TKI). To provide context, FOLFIRINOX typically has an improved survival of approximately 11 months, while gemcitabine or gemcitabine plus erlotinib elicit a 6-7 month improvement in median overall survival (MOS).  Erlotinib added 12 days of extra survival over gemcitabine alone, but unfortunately we have no way of selecting those advanced pancreatic patients most likely to respond to EGFR therapy.

Celgene is exploring the combination of Abraxane and Gemzar based on preclinical work that suggests Abraxane can knock out the protective stroma surrounding the tumor, thereby providing better penetration of the tumor.  The phase II data led to a promising 12.2 months improvement in median overall survival.

In general, results from randomized phase III trials tends to be lower than that reported in the smaller studies. This is exactly what happened in the MPACT trial, with the Abraxane combination showing a MOS of 8.7 months versus 6.7 months for Gemzar alone, a highly statistical significant finding (P<0.000015). The hazard ratio (HR) was 0.72, suggesting that the combination gave a 28% reduction in the risk of death versus gemcitabine.

Kindler is eager to use and learn more about the combination and notes that it will be another option for oncologists rather than a new standard of care.

This is encouraging data and met the primary endpoint. Celgene is expected to file for approval for Abraxane in advanced pancreatic adenocarcinoma in the second half of the year. Data on a previously identified biomarker (SPARC expression) was not yet available and is expected to be presented at the annual ASCO meeting in June.  The audience at the GI meeting were clearly expecting survival to be higher in those patients with high SPARC expression, but we will see what happens.

Advanced pancreatic cancer is a particularly devastating disease – the incidence and prevalence are approximately equal, with patients typically having a year of life left.  The symptoms are vague and insidious plus there are no useful screening approaches approved for earlier detection, so the emergence of potential biomarkers for selecting patients most likely to respond to Abraxane or Tarceva in combination with gemcitabine would be a most welcome advance, especially given the toxicities associated with FOLFIRINOX.

 

 

#FoodChem Carnival: A bit o’ science on your Thanksgiving tippling

In my family, the first thing that happens when you walk in the door to my Aunt Kim’s house on Thanksgiving is you find yourself on the receiving end of the world’s best hug. The second thing that happens is a glass of champagne is thrust into your hand. So when I sat down to consider how to contribute to this week’s Thanksgiving-inspired #foodchem carnival, the science of champagne seemed a natural fit. And since some might consider champagne medicinal, it can squeeze by at the Haystack, right?

Anything you want to know about the science of champagne can pretty much be learned from Gérard Liger-Belair, a professor of chemical physics at the University of Reims Champagne-Ardenne. Liger-Belair has possibly the best job in existence: he spends his days trying to decipher the chemistry and physics of champagne. We covered some of his tips for champagne serving here (most practical for every day imbibing: don’t use soap to wash your flutes. Instead, rinse with hot water and wipe with a towel. The cellulose fibers left behind from your swipe promote effervescence.).

More recently, Liger-Belair has come out with evidence that size does matter—bottle size, that is. The smaller the bottle, the lower the concentration of dissolved CO2 in each successive glass poured. The message here: forget those wimpy splits, and go magnum. But if you do have a smaller bottle (okay, or a normal 750mL bottle), you can maintain some of the effervescence by keeping nice and frosty. Meanwhile, if you want to enjoy that nose-tickling fizz at the top of your glass for longer, this study suggests you should pick a flute over a coupe. This family prefers a flute, anyway. Less spillage.

So there you have it. Happy Turkey Day, all!

For more on the science of champagne, check out:

What’s that Stuff: Champagne:

http://pubs.acs.org/cen/whatstuff/stuff/8201champagne.html

Unraveling different chemical fingerprints between a champagne wine and its aerosols:

http://www.pnas.org/content/106/39/16545

Uncorked: The Science of Champagne:

http://press.princeton.edu/titles/7811.html

Cantley Talks Pfizer CTI Collaboration

As drug companies forge closer ties with academic researchers, the value of pharma-academia partnerships continues to be cause for much debate (see here, here,  here, and here for more on that). We’ve watched the evolution of these collaborations with interest, and as part of our ongoing coverage, this week’s issue brings an in-depth look at the mechanics of Pfizer’s Centers for Therapeutic Innovation, its network of academic partners centered on hubs in San Francisco, New York, Boston, and San Diego.

But much of our focus has been on what drug companies can gain from deeper ties with academia. There’s another side to the coin: what the academic lab gains from teaming up with industry. While visiting Pfizer’s Boston CTI, I was glad to have a long chat with Harvard’s Lewis Cantley, known in cancer research circles for the discovery of the PI3K pathway, about why it made sense to link up with Pfizer.

Cantley has had many pharma partnerships, was a founder of Agios Pharmaceuticals, and has sat on the boards of other start-ups. As such, I was curious what made him want to turn to Pfizer for this particular project—developing a drug against a cancer target discovered in his lab–rather than go at it alone, or try to spin out another company.

Cantley conceded that his lab could have plugged away at the target for several years and eventually come up with something promising. But the target requires an antibody, and his lab is more experienced at discovering small molecules. Pfizer, meanwhile, could step in with expertise and technology that they otherwise would never have access to, significantly speeding up the drug discovery process.

Further, Pfizer made teaming up easy. “The legalities of conflict of interest issues and IP issues had all been addressed with negotiations between Harvard and Pfizer before they even solicited proposals,” Cantley says. “To me, this was huge.” He notes that past partnerships with industry have involved at least a year of negotiating before anyone gets down to doing business—or, as it may be, science.

Another positive was that working with Pfizer meant researchers in his lab could continue to be involved with the project. When Cantley became a founder of Agios, which focuses on developing drugs that interrupt cancer cell metabolism, he could no longer ethically allow students in his lab work on that aspect of the science. But under the Pfizer pact, post-docs can continue to explore the drug development as well as any basic biological questions that may arise.

Lastly, Cantley was attracted by the facility with which Pfizer and academic scientists could interact. As it turns out, Cantley’s labs are in the same building as Pfizer’s Boston CTI. “It’s literally two minutes to get from my lab to theirs,” he notes. The seamless exchange of reagents and technologies occurs at a “speed which just doesn’t happen with other industry collaborations,” he says.

Indeed, as the story discusses, Pfizer is banking on that proximity to enable good targets or lead molecules to be quickly moved from the bench to the bedside. The goal is to have three to four compounds in human trials in the next 18 months—a swift turnaround considering the first CTI, a partnership with UCSF and labs in San Francisco, was announced just two years ago.

Sanofi’s MS Pill Aubagio Wins FDA Approval

Another pill for multiple sclerosis has gotten FDA’s stamp of approval. Sanofi’s Aubagio is expected to hit the market in a few weeks, making it only the second oral drug available to people with MS. Novartis’ MS pill Gilenya, which works by a different mechanism of action than Aubagio, has been on the market for two years.

Aubagio will cost roughly $45,000 a year, strategically priced below the leading MS drugs on the market. As Leerink Swann analyst Seamus Fernandez pointed out today in a note, that puts it at about 6.5% lower than Teva’s Copaxone, 8% less than Biogen Idec’s Avonex, and 28% below the price of Gilenya. “We continue to be surprised by the magnitude of price increases within the MS market overall and view Sanofi’s slight discount as reasonable,” he added.

As we described back in 2009, MS is a problem of an immune system gone awry, with lymphocytes first attacking myelin, the protective sheath on nerve fibers, and eventually breaking down the fibers themselves. The first wave of MS drugs—beta-interferons like Avonex and Copaxone–intercept T-cells to slow down the body’s immune response. But that approach is promiscuous—the beta-interferons also prompt widespread gene expression, and cause flu-like side effects.

The latest wave of MS treatments take a more refined approach to reining in the immune system. Biogen’s Tysabri, for example, blocks alpha-4-beta-1 integrin, which signals immune cells to leave the bloodstream and enter the brain and spinal cord. Gilenya keeps some T-cells out of the bloodstream by binding to sphingosine-1-phosphate receptor, thereby preventing some white blood cells from leaving the lymph nodes. Aubagio, meanwhile, inhibits dihydroorotate dehydrogenase, a critical enzyme in the synthesis of pyrimidine, which activated white blood cells need to survive. Whereas the beta-interferons have a sweeping effect on the immune system, some pathways are maintained with Aubagio’s activity.

Aubagio has a few advantages over Gilenya and Tysabri: namely, it does not carry the same safety risks associated with those drugs (see here and herefor more on that), and is taken orally just once a day.

But Aubagio also has its downsides. On the efficacy front, its milder interaction with the immune system renders it less effective than the more hard-hitting treatments. And it can cause hair loss and birth defects, a serious limitation for women of childbearing age—as Fernandez points out in his note, a large population in the MS community.

#ASCO12 Data Digest: Combating Resistance in Lung Cancer

The following is a guest post from Sally Church (known to many in the twittersphere as @MaverickNY), from the Pharma Strategy Blog.

The American Society of Clinical Oncology (ASCO) meeting, held in Chicago earlier this month, brought some fascinating presentations on progress in two very tough to treat cancer types, lung cancer and advanced melanoma. This week, we’ll take a look at some of the data that emerged out of ASCO on small molecules that could overcome the limitations of existing therapies.

Treatment for lung cancer and melanoma has commonalities. Small molecule kinase inhibitors targeting a particular aberration driving the tumor have been approved for both types of cancer. But in each case, tumors eventually develop resistance to those kinase inhibitors, usually after about 6 to 9 months of treatment. Researchers are now trying to pinpoint the mechanism that tumor cells use to overcome the activity of kinase inhibitors, and then design new compounds or combinations of drugs that can improve patient outcomes.

Today we’ll focus on advances in non-small cell lung cancer (NSCLC). ASCO brought data from several new agents—most notably, Boehringer Ingelheim’s afatinib, AstraZeneca’s selumetinib, and Novartis’ LDK378—as well as new combinations of existing drugs.

First, some background on the current treatment paradigm in NSCLC: To date, scientists have identified several key protein receptors—EGFR, KRAS, and ALK—as drivers of the disease. Patients with a mutation in EGFR can take Genentech’s Tarceva (erlotinib) or AstraZeneca’s Iressa (gefitinib), but only after undergoing four cycles of chemotherapy. Although Tarceva was approved based on its ability to shrink tumors, it only prolongs survival in NSCLC patients by one month (12 months Tarceva vs. 11 months for placebo). Meanwhile, people who have the anaplastic lymphoma kinase (ALK-ELM4) translocation, can receive Pfizer’s Xalkori (crizotinib), which was approved in the U.S. in 2011.

Unfortunately, people with the KRAS mutation, which is considered mutually exclusive with EGFR, do not benefit from either additional chemotherapy or EGFR inhibitors. New therapies are desperately needed, since prognosis tends to be rather poor.

At ASCO this year, clinicians reported new data that answered some key questions about how best to treat people with these particular mutations: Continue reading →

#BIO2012: Pfizer’s academic push by the numbers

The evolution of the model for academic-pharma collaboration has been a topic of much discussion as more companies try to tap into university talent for early-stage research (recent examples of collaborations can be found here and here). Industry observers question whether anything tangible will come out of the efforts (see here for a recent critique), believing the divergent missions and cultural differences of each organization inevitably sidelines these pacts.

Pfizer is making one of the more aggressive pushes through its Centers for Therapeutic Innovation. Under the CTI model, Pfizer has set up labs in research hotbeds like Boston and San Francisco, where, through partnerships with various academic institutions, its scientists work side-by-side with university scientists to discover new biologics-based drugs. This week at BIO, I sat down with Tony Coyle, CTI’s chief scientific officer, to talk about CTI’s progress. A more in-depth look at the CTI model will come in the pages of the magazine, but in the meantime, I wanted to share some facts and figures that came out of our chat:

Number of CTIs formed: Four (San Francisco, San Diego, New York, Boston)

Number of academic centers involved: 20

Number of Pfizer scientists across each of its dedicated labs: roughly 100 (Coyle says about 75% were hired from the outside, coming from biotech, academia, with a few from big pharma)

Number of proposals reviewed in the last year: 400

Percentage of proposals overlapping with internal Pfizer efforts: <5%

Number of proposals funded so far: 23

Number of therapeutic areas being studied: 4 (rare diseases, inflammation, cardiovascular disease, and oncology)

Facts and figures aside, Pfizer is trying to move as quickly as possible given the learning curve of teaming with academia. Coyle said he’s promised his bosses that by the third year of the effort, at least four drugs will be in human studies across multiple therapeutic areas. “We’re well on our way to identifying a number of candidates, and I have no doubt that in the next 18 months, we’ll be in our first patient studies,” he added.

Those numbers could change in 2013, when Pfizer potentially expands its CTI outside the U.S. “Ex-U.S is still our ambition,” Coyle says. “2012 has been a period of ‘lets build the group, get the programs and start executing on the pipeline.’ For 2013, we will be and are looking at opportunities ex-U.S., and have had some pretty good discussions to date externally.”

Tetrodotoxin: Why Toxic Is Complicated

(This post was written for the “Our Favorite Toxic Chemicals” blog carnival hosted by Sciencegeist.)

It was a meal Captain James Cook would just as soon have forgotten. The fish, an unfamiliar species, seemed harmless enough. But after just a small taste of its liver, he and two shipmates regretted it.

“We were seized with an extraordinary weakness in all our limbs attended with a numness [sic]…We each of us took a Vomet and after that a Sweat which gave great relief. One of the pigs which had eat the entrails was found dead… When the Natives came on board and saw the fish hanging up, they immidiately [sic] gave us to understand it was by no means to be eat.”

Cook had a rather more dramatic introduction to the lethal chemical tetrodotoxin than I did. I learned about it from a lecture in a windowless room. (Yes, I’ve linked to the original slides, still online after eight years.) That presentation had plenty to make my ears perk up. Highly poisonous. No antidote. Still kills today, because pufferfish, one of the web of creatures that makes tetrodotoxin, gets carved into a delicacy called fugu, and sometimes those knives miss a little bit of the animal’s toxic innards.

We weren’t learning about tetrodotoxin because of its deadliness. Tetrodotoxin, to the organic chemist, is a case study. The lab where I earned my Ph.D. is in the business of making the toughest molecules it can. The lessons teams learned by forging tetrodotoxin from scratch, the idea goes, will be useful in other endeavors. Chemists for decades have argued about whether this is an appropriate way to train students, but suffice to say it’s still the way that most medicinal chemists in pharma get their start.

Tetrodotoxin is different things to different people. To biochemists and neurobiologists, tetrodotoxin, or TTX for short, is a tool for unraveling how pain works. Researchers today know that TTX binds to sodium channel proteins involved with pain pathways in the nervous system.

To those who study the cultures of Haiti, tetrodotoxin evokes something else entirely– the zombie of Haitian tradition.

In the 1980s, ethnobotanist Wade Davis fingered tetrodotoxin as a key ingredient in a powder witch doctors use in voodoo zombie-making rituals. His doctoral thesis, as well as his bestselling book the “The Serpent and the Rainbow”, about the topic eventually became the basis for a movie of the same name.

Davis’s results came under fire from the medical and scientific community. Another team’s measurements of tetrodotoxin levels in the powder detected amounts too low to have any relevant effects, though Davis and another set of researchers have countered that fluctuations in pH dramatically affect those levels.

Tetrodotoxin levels aside, “the main criticism of Wade’s hypothesis is that tetrodotoxin does not confer the long term fugue that would be necessary to keep someone in a wakeful but zombified state,” says Frank Swain, a science writer currently working on a book about zombies. Swain also points to clinical examinations of three purported zombies, where each was diagnosed with a mental illness. “It seems zombies are just normal people with learning difficulties, who become pawns in various feuds as one family accuses another zombifying their children,” Swain says.

Davis, today an explorer-in-residence at the National Geographic Society, defends his work, saying that examining zombies with a purely chemical lens ignores their cultural context. “The zombie definition in Haiti has nothing to do with the poison,” he says. “Of course tetrodotoxin cannot make a zombie, but it can make someone appear to be dead.” From there, the belief system takes over and makes tetrodotoxin “the obvious culprit,” he adds.

Whether or not you adhere to the Haitian belief system, tetrodotoxin is a chemical that’s not to be messed with. Yet somehow fugu emerged as a delicacy. Customers line up, as the BBC puts it, to “play Russian roulette at the dinner table”. Consuming fugu is a much bigger gamble than consuming a burger made with the infamous meat product “pink slime”. But it was the slime that got the outrage.

It all comes down to information and choice. According to economist Robin Hanson, America is much more paternalistic when it comes to regulating foods consumed by the poor and by children, presumably because people feel those groups are unable to obtain or act on the information they’d need to make informed food choices.

Preserved pufferfish at the Heard Natural Science Center, Fairview, Texas (Flickr/gurdonark)

With fugu, folks know what they’re in for. They’re aware of the risk, though they may be less aware of the black-market trade in pufferfish, or of Tokyo’s recent move to ease strict regulations about who can serve it. And it doesn’t end with food. Hairstylists and consumers didn’t know that the cancer-causing chemical formaldehyde was in the hair-straightener Brazilian Blowout, because of the company’s deceptive marketing. Now that they do, some people beg for it anyway, and drop hundreds of dollars a pop to do it.

Our relationship with toxic chemicals is complicated. It isn’t always Nick Kristof’s “Big Chem” that’s out to obscure dangers or cloud our judgement. Sometimes, it’s human nature. We know smoking’s bad for us, and we do it anyway. But we don’t always know what lurks in, for example, a trailer provided by FEMA. Painting chemicals as “evil” or “good” is too simplistic- it’s all about their doses and their context. Instead of op-eds “teaching nothing more than a generalized chemical anxiety”, as Deborah Blum eloquently wrote, the world would be better served by op-eds that call for better information on what chemicals’ danger thresholds are. It’s a nuanced mission, but I’d venture a paper of the New York Times’ caliber is up to it.

Epizyme & Celgene to Develop Epigenetics-Based Cancer Drugs

Cambridge, Mass.-based Epizyme has scored $90 million upfront as part of a broad cancer drug development pact with Celgene. The deal adds to a spate of lucrative pacts to find compounds to modulate epigenetic targets, or enzymes that control gene expression without altering the underlying DNA.

As we wrote in last week’s cover story, DNA carries the instructions for assembling all of life’s essential building blocks, but epigenetics dictates how and when that DNA is put to work. Recently, companies have made significant process in understanding the complex biology behind epigenetic processes, while also figuring out how to design compounds that can potently block epigenetic enzymes. With the science and business rationale for pursuing epigenetic targets dovetailing, big pharma and big biotech alike are forging deep ties with the handful of companies with expertise in the field.

Under the three-year deal announced today, Celgene has the right to opt-in to the ex-U.S. rights for any unencumbered histone methyl transferase program at Epizyme. Eisai currently has the rights to Epizyme’s EZH2 inhibitor, while GlaxoSmithKline has a deep collaboration with Epizyme against undisclosed targets that would be excluded from today’s pact with Celgene.

Epizyme says the partnership makes sense because Celgene shares “our vision in oncology and epigenetics,” says Epizyme’s president and CEO Robert J. Gould. “That’s been a fundamental bedrock of our partnering strategy–to partner with people who share our enthusiasm for this space.”

Indeed, Celgene has long played in the epigenetics space, boasting two of the four currently marketed drugs that act on epigenetic targets. However, Celgene’s drugs, Istadax and Vidaza, hit first-generation epigenetic targets. Epizyme’s activities, meanwhile, center on one of the next waves of epigenetic targets: a family of enzymes called histone methyltransferases (HMTs). Of the 96 members of that family, Epizyme has identified roughly 20 HMTs for which there is a clear link to a specific form of cancer, Gould says.  To date, the company has two compounds—the EZH2 inhibitor partnered with Eisai, and a DOT1L inhibitor—in preclinical studies. (Check out last week’s cover story on epigenetics for more on how Epizyme went about discovering those two compounds.)

Celgene is kicking off the pact by opting into the inhibitor of DOT1L, an HMT that is implicated in mixed lineage leukemia, a rare subtype of the blood cancer that the Leukemia and Lymphoma Society says affects about 1,500 new patients in the U.S. each year.

With each program thereafter that Celgene buys into, Epizyme could score up to $160 million in milestone payments.

The cash influx, coupled with the U.S. rights to the programs, “positions us nicely to maintain our independence, but also control our own future as a company,” Gould says. “We now have the runway to go pretty far with these programs.”

That independence is important aspect of Epizyme’s strategy of commercializing its cancer therapies in the U.S., a goal Gould says is attainable because HMT inhibitors will be used in highly specific, genetically-defined patient populations.

The Celgene deal also broadens Epizyme’s scientific horizons, Gould says. “This expands the depth of research we can do around histone methyl transferases specifically…but also gives us the opportunity to imagine what other approaches we might take that might be synergistic or additive to the HMT family.”

Gould is quick to note that in the near term, the company is focused on HMTs “until we prove these compounds are effective in these patients with genetically-defined cancer.”

Between its deals with GSK, Eisai, and Celgene, and its burgeoning pipeline, Epizyme will need to expand its operations. The current headcount stands at about 48, but Gould notes that going forward the small biotech will need to grow out its clinical development organization and, more modestly, its basic research activities.