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Merck Jumps into Antibody-Drug Conjugates With Ambrx Deal

Merck today has jumped into what has become one of the hottest areas in oncology, antibody-drug conjugates, through a deal with San Diego-based Ambrx. Merck will pay $15 million upfront and up to $288 million in milestones for access to Ambrx’s site-specific protein conjugation technology.

Coincidentally, on the cover of today’s magazine, we take a look at the future of antibody-drug conjugate technology. Although people have been working on ADCs for three decades, interest in the approach has reached fever pitch after last year’s approval Seattle Genetics’ lymphoma drug Adcetris and the recent hubbub at ASCO over positive interim Phase III data for Genentech’s T-DM1.

The idea behind ADCs is simple: use a targeted antibody to deliver a highly potent chemotherapeutic to a cancer cell, sparing healthy cells. But current ADC technology has limitations. This week’s cover story looks at efforts to improve upon each component—the antibody, the small molecule, and the “linker” that connects the two.

Ambrx is focused on the antibody, using site specific protein conjugation technology to better control how many and where small molecules are placed on an antibody. Currently, companies manufacturing ADCs (most using technology from Seattle Genetics or ImmunoGen) wind up with a heterogenous product—each ADC has anywhere from zero to eight small molecules attached to the protein, but on average, 3.5 to four small molecule “payloads” linked. The placement of the payloads on the antibody also varies, leading to families of conjugates. As I explain in today’s story, even among the ADCs with four small molecules attached, some have all the cytotoxins clustered in one region, but they might be spread out on others.

Ambrx incorporates a nonnatural amino acid into the antibody to allow precise placement of the drug payload. As I explain:

Ambrx can insert p-acetyl-phenylalanine onto two sites of the antibody. The phenyl- alanine derivative has been modified to include a ketone that acts as a functional group for conjugation to the linker and small molecule.

Although Ambrx can attach more than two chemistry “handles” to the antibody, its studies have shown that two small molecules make the most sense. “You really want to be mindful about preserving the native structures and function of the antibody, while trying to optimize therapeutic activity,” says Chief Technology Officer Ho Cho. “The more you stray away from that, the more risks there are in drug development.”

The beauty of site-specific conjugation, researchers say, is that it allows them to me- thodically determine which ADC variety is the most active. “We can specifically attach whatever payload-linker combo we wish and do quantitative experiments to find out how it works,” Cho says. His team tests biophysical stability, pharmacokinetics, and efficacy to understand how much of the drug can be given before toxicity kicks in.

The ADCs in the current clinical pipeline are all to combat cancer, but Ambrx believes its site-specific conjugation technology will open the door to using ADCs in other therapeutic areas. As Cho told me, the heterogeneous nature of current ADCs has limited their use. “What we’re excited about is taking this into non-oncology indications,” Cho says. “We’ve started to generate some interesting pre-clinical data sets…This is where Ambrx really thinks the field is moving.”

It’s worth noting is that Ambrx was founded by Scripps Research Institute’s Peter Schultz, who Merck recently appointed head of Calibr, a San Diego-based non-profit funded by the big pharma firm that will act as a vehicle for academic scientists to turn their ideas into drug candidates. For more on Calibr, click here.

 

 

 

Haystack 2011 Year-in-Review

Well, 2011 is in the books, and we here at The Haystack felt nostalgic for all the great chemistry coverage over this past year, both here and farther afield. Let’s hit the high points:

1. HCV Takes Off – New treatments for Hepatitis C have really gained momentum. An amazing race has broken out to bring orally available, non-interferon therapies to market. In October, we saw Roche acquire Anadys for setrobuvir, and then watched Pharmasset’s success with PSI-7977 prompt Gilead’s $11 billion November buyout.  And both these deals came hot on the heels of Merck and Vertex each garnering FDA approval for Victrelis and Incivek, respectively, late last spring.

2. Employment Outlook: Mixed – The Haystack brought bad employment tidings a few times in 2011, as Lisa reported. The “patent cliff” faced by blockbuster drugs, combined with relatively sparse pharma pipelines, had companies tightening their belts more than normal. Traffic also increased for Chemjobber Daily Pump Trap updates, which cover current job openings for chemists of all stripes. The highlight, though, might be his Layoff Project.  He collects oral histories from those who’ve lost their jobs over the past few years due to the pervasive recession and (slowly) recovering US economy.. The result is a touching, direct, and sometimes painful collection of stories from scientists trying to reconstruct their careers, enduring salary cuts, moves, and emotional battles just to get back to work.

3. For Cancer, Targeted Therapies – It’s also been quite a year for targeted cancer drugs. A small subset of myeloma patients (those with a rare mutation) gained hope from vemurafenib approval. This molecule, developed initially by Plexxikon and later by Roche / Daiichi Sankyo, represents the first success of fragment-based lead discovery, where a chunk of the core structure is built up into a drug with help from computer screening.From Ariad’s promising  ponatinib P2 data for chronic myeloid leukemia, to Novartis’s Afinitor working in combination with aromasin to combat resistant breast cancer. Lisa became ‘xcited for Xalkori, a protein-driven lung cancer therapeutic from Pfizer. Researchers at Stanford Medical School used GLUT1 inhibitors to starve renal carcinomas of precious glucose, Genentech pushed ahead MEK-P31K inhibitor combinations for resistant tumors, and Incyte’s new drug Jakifi (ruxolitinib), a Janus kinase inhibitor, gave hope to those suffering from the rare blood cancer myelofibrosis.

4. Sirtuins, and “Stuff I Won’t Work With  – Over at In the Pipeline, Derek continued to chase high-profile pharma stories. We wanted to especially mention his Sirtris / GSK coverage (we had touched on this issue in Dec 2010). He kept up with the “sirtuin saga” throughout 2011, from trouble with duplicating life extension in model organisms to the Science wrap-up at years’ end. Derek also left us with a tantalizing tidbit for 2012 – the long-awaited “Things I Won’t Work With” book may finally be coming out!

5. Active Antibacterial Development – In the middle of 2011, several high-profile and deadly bacterial infections (Germany, Colorado, among others) shined a spotlight on those companies developing novel antibacterials. We explored front -line antibiotics for nasty Gram-negative E.coli, saw FDA approval for Optimer’s new drug Fidiclir (fidaxomicin) show promise against C. difficile  and watched Anacor’s boron-based therapeutics advance into clinical testing for acne, and a multi-year BARDA grant awarded to GSK and Anacor to develop antibacterials against bioterrorism microorganisms like Y. pestis.

6. Obesity, Diabetes, and IBS – Drugs for metabolic disorders have been well-represented in Haystack coverage since 2010. Both Carmen and See Arr Oh explored the vagaries of Zafgen’s ZGN-433 structure, as the Contrave failure threatened to sink obesity drug development around the industry. Diabetes drugs tackled some novel mechanisms and moved a lot of therapies forward, such as Pfizer’s SGLT2 inhibitors, and Takeda’s pancreatic GPCR agonist. Ironwood and Forest, meanwhile, scored an NDA for their macrocyclic peptide drug, linaclotide.

7. The Medicine Show: Pharma’s Creativity Conundrum – In this piece from October, after Steve Jobs’ passing, Forbes columnist Matt Herper both eulogizes Jobs and confronts a real ideological break between computer designers and drug developers. His emphasis? In biology and medical fields, “magical thinking” does not always fix situations as it might in computer development.

We hope you’ve enjoyed wading through the dense forest of drug development with Carmen, Aaron, Lisa, and See Arr Oh this past year. We here at The Haystack wish you a prosperous and healthy 2012, and we invite you to come back for more posts in the New Year!

Macrocycle Milestone for Ironwood Pharma

Ironwood Pharmaceuticals and Forest Laboratories last week announced submission of an NDA for linaclotide, a peptide macrocycle for treatment of irritable bowel syndrome (IBS). This is the first new drug application for Ironwood, a 13-year old Cambridge, MA company, and it could validate other companies’ strategies for large-ring drugs (covered recently by Carmen Drahl in C&EN). There’s an enormous potential market for this drug; by Ironwood’s count, a combined 45 million people in the US suffer from IBS and related chronic constipation (CC), yet few drugs are approved for these conditions. So, how does linaclotide help IBS sufferers, um . . . go?

This 14-amino acid peptide ring, taken orally, arrives at the intestinal lumen, where, according to Ironwood patent literature, it docks with a receptor enzyme called guanylate cyclase C (GC-C). The extracellular domain (part that sticks out of the cell membrane), upon binding, initiates the intracellular domain (inside the cell) to begin production of guanosine-3’, 5’-cyclic monophosphate (cGMP), a signaling molecule that induces changes in the intestinal wall. In short, cGMP prompts the intestinal surface to release chloride and bicarbonate ions into the intestinal tract, which decreases sodium uptake and increases fluid secretion (Note: interestingly, this is similar to the body’s response upon E.coli infection; a bacterial toxin called ST-peptide causes traveller’s diarrhea). In Ironwood’s own words, these physiological changes “accelerate intestinal transit,” which helps to move solid waste and decrease overall pain by acting on local nerve responses.

Update (3:20PM, 8/17/11) – Changed “nearly 45 million people in the US alone suffer from IBS, yet few drugs are approved for this condition” to “combined 45 million people in the US suffer from IBS and related chronic constipation (CC), yet few drugs are approved for these conditions.”

Amgen Discusses Biosimilars Strategy

Yesterday, Amgen held its first business strategy meeting since the fall 2008, and mixed in with much talk of its bone-loss treatment denosumab was a discussion of its strategy around biosimilars. The company gave its view of the impact of generic versions of its biologic drugs in Europe and the U.S., as well as the opportunity for its own growth in the space.

Several core drugs in the Amgen portfolio will be under pressure from biosimilars after 2015, but management downplayed the impact the competition would have on its business. Because of their complexity, biosimilars aren’t subject to the same “patent cliff” small molecules face when their patent expires, Amgen’s CEO Kevin Sharer said. And although the company expects biosimilars to exist in the U.S., and for prices to be impacted, “we do not expect revenues to go away overnight,” he added.

Although U.S. regulatory authorities have yet to sort out a pathway for approving biosimilars, generic entrants have already made their way into European markets. Biosimilars have taken over about 6% of the market for Amgen’s anemia treatment Aranesp, and pricing has been “pretty disciplined” after their first few months on the market, noted Amgen’s president and chief operating officer Robert A. Bradway. European market share for biosimilar competitors to Amgen’s filgrastim franchise, which includes the multi-million dollar seller Neulasta, has also stayed steady at around 6%.

At the same time, Sharer cautioned that things will not play out identically to the U.S. and Europe. Further, he reminded the audience that “there is no such place as Europe—that’s some figment of a travel agent’s imagination.” The experience across countries has not been uniform, and generic erosion has occurred much faster in some countries than others.

Still, looking back to Amgen’s expectations for the impact of biosimilars had been far bleaker than what has occurred so far in Europe. “Frankly, if we’d beeen sitting here inside an Amgen meeting five years ago…we’d have anticipated a different outcome” regarding biosimilars, Sharer added.

Amgen’s chief also pointed out that because Amgen has such broad experience in developing and manufacturing large molecules, there could be a significant upside as the company starts to compete in the biosimilars arena. The business won’t immediately skyrocket after 2015, “but in the several years after that, it has multi-billion dollar potential for us,” he said.

The company has created a small biosimilars unit, and Sharer says that in talking with partners it appears that establishing a presence in the arena “will not require much investment on our part.”

Haystack 2010 Year-In-Review

This Friday, we’re looking back at 2010′s big news in pharma and biotech, both the good and the bad. Check out our picks and be sure to weigh in on what you think we missed.

1. Provenge Approved

In April, Dendreon’s Provenge became the first approved cancer immunotherapy. Dendreon CEO Mitch Gold called it “the dawn of an entirely new era in medicine.” And while prostate cancer patients are excited for a new treatment option, the approval is perhaps most exciting for its potential to reignite interest in cancer immunotherapy research. There’s a lot of room for improving the approach—Provenge is, after all, expensive and highly individualized. Now that immunotherapy have been proven to work, there’s hope that the lessons learned in both its discovery and clinical development will aid scientists in inventing even better cancer vaccines.

2. Obesity Field Slims

The obesity drug race played out in dramatic fashion in 2010, with three biotech companies-Vivus, Arena, and Orexigen, each making their case for its weight-loss medication before FDA. As of this writing, Orexigen’s drug Contrave seems to be on the surest footing to approval, but longtime obesity-drug watchers know that caution seems to rule the day at FDA, so nothing is a sure bet.

Orexigen’s Contrave and Vivus’s Qnexa are both combinations of already-approved drugs, whereas Arena’s Lorqess is a completely new molecule. When C&EN covered the obesity race in 2009, it seemed that Lorqess (then going by the non-brand-name lorcaserin) had the cleanest safety profile, but Qnexa was best at helping patients lose weight.

But FDA’s panels didn’t always play out the way folks expected. There were safety surprises- notably the worries about tumors that cropped up in rats on high doses of Lorqess, and the extensive questioning about birth defect risks from one of the ingredients in Vivus’ Qnexa. The fact that FDA’s panel voted favorably for Orexigen’s Contrave, a drug that’s thought to have some cardiovascular risks, generated discussion because FDA pulled Abbott’s Meridia, a diet drug with cardiovascular risks, from the market in October.

The dust still hasn’t fully settled. Arena and Vivus received Complete Response Letters from FDA for Lorqess and Qnexa. Vivus has submitted additional documentation and a followup FDA meeting on Qnexa is happening in January. Also to come in January is the agency’s formal decision on Contrave. And if you’re interested in learning about the next wave of obesity drugs coming up in clinical trials, read this story in Nature News.

3. Sanofi & Genzyme: The Neverending Story

Speaking of drama, Sanofi’s pursuit of Genzyme has been in the headlines for months now, and promises to stretch well into 2011. The story goes something like this: Genzyme had a tumultuous year, as it struggled to correct the manufacturing issues that created product shortages and eventually led to a consent decree with FDA. In walked Sanofi, who offered—in a friendly way—to buy the company for $18.5 billion. Genzyme refused to consider what it viewed as a lowball offer. Weeks passed, they remained far apart on price with no signs of anyone budging, until Sanofi finally went hostile. Genzyme suggested it would be open to an option-based deal, which would provide more money later on if its multiple sclerosis drug candidate alemtuzumab reached certain milestones. Sanofi stuck to its $18.5 billion guns and is now trying to extend the time period to convince shareholders to consider its offer.

4. Final Stretch in HCV Race

This year, the industry finally got a peek at late-stage data for what are likely be the first drugs approved for Hepatitis C in more than two decades. Based on Phase III data, analysts think Vertex’s telaprevir will have an edge over Merck’s boceprevir once the drugs hit the market. Meanwhile, the next generation of HCV drugs had a bumpier year, with several setbacks in the clinic. Still, the flood of development in HCV has everyone hoping that eventually people with HCV can take a cocktail of pills, rather than the current harsh combination of interferon and ribavirin.

5. Pharma Covets Rare Diseases

Historically, research in rare diseases has been relegated to the labs of small biotechs and universities. But in 2010, big pharma firms suddenly noticed that if taken in aggregate, a pretty sizable chunk of the public—on the order of 6%–suffer from rare diseases. They also noticed that when there’s a clear genetic culprit, drug discovery is a bit more straightforward. Further, rare disease can sometimes be a gateway to approval in larger indications, making them all the more appealing. With that, Pfizer and GlaxoSmithKline both launched rare diseases units and made a series of acquisitions and licensing deals (Pfizer/FoldRxGSK/AmicusGSK/Isis, etc) to accelerate their move into the space. Meanwhile, Sanofi is trying to jump in with both feet through its proposed acquisition of Genzyme.

6. MS Pill Approved

Novartis gained approval in September for Gilenya, the first treatment for multiple sclerosis that is a pill rather than an injection. In even better news for people with MS, there more pills are rounding the corner towards FDA approval: Sanofi’s teriflunomide, Teva’s laquinimod, and Biogen’s BG-12. All of these drugs come with safety caveats, but the idea of new treatment options after years depending on interferons has gotten everyone in the MS field pretty excited.

7. Antibody-Drug Conjugates Prove Their Mettle

The concept of linking a powerful chemo drug to a targeted antibody, thereby creating something of a heat-seeking missile to blast tumor cells, isn’t new. But antibody-drug conjugate technology has finally matured to a point where it seems to be, well, working. Seattle Genetics presented very positive results from mid-stage studies of SGN-35 in two kinds of lymphoma. And ImmunoGen provided clear data showing its drug T-DM1 could significantly minimize side effects while taking down breast cancer.

8. Pharma Forges Further into Academia

With nearly every pharma firm paring back internal research, the focus on external partnerships has never been greater. Broad deals with universities are becoming more common, and Pfizer has arguably gone the furthest to evolve the model for working with academic partners. In May, Pfizer announced a pact with Washington University under which the academic scientists will look for new uses for Pfizer drug candidates. As part of the deal, they gain unprecedented access to detailed information on Pfizer’s compound library. And last month, Pfizer unveiled the Center of Therapeutic Innovation, a network of academic partnerships intended to bridge the “valley of death,” between early discovery work and clinical trials. The first partner is University of California, San Francisco, which scores $85 million in funding over five years, and the network will eventually be comprised of seven or eight partners, worldwide. Most notable is that Pfizer is planting a lab with a few dozen researchers adjacent to the UCSF campus to facilitate the scientific exchange.

9. Finally, New Blood Thinners

This year saw the FDA approval of a viable alternative to coumadin (aka warfarin), a 50-plus-year-old workhorse blood thinner that interacts with many foods and herbal supplements.

Boehringer’s Pradaxa (dabigatran) got a unanimous thumbs-up from an FDA panel for preventing stroke in patients with a common abnormal heart rhythm called atrial fibrillation. FDA approved the drug in October. The next new warfarin alternative to be approved could be Xarelto (rivaroxaban), which has had favorable results in recent Phase III clinical trials, as David Kroll over at Terra Sig explained. Both Xarelto and Pradaxa had already been approved for short term use outside the US.

Rivaroxaban and dabigatran work at different stages of the biochemical cascade that leads to clotting, as we illustrated here. Another drug candidate in the warfarin-alternative pipeline is BMS’s and Pfizer’s apixaban. Check out coverage of apixaban trials here and at Terra Sig. And in a separate blood-thinner class, FDA today rejected Brilinta, a possible competitor to mega-blockbuster Plavix.

10. Alzheimer’s Progress & Setbacks

Alzheimer’s disease has been a tough nut to crack, and news in 2010 has done little to dispel this reputation. This year Medivation’s Dimebon, which started life as a Russian antihistamine and showed some promise against Alzheimer’s, tanked in its first late-stage clinical trial. Later in the year, Eli Lilly halted development of semagacestat after the compound actually worsened cognition in Alzheimer’s patients. Semagacestat targeted the enzyme gamma-secretase, and the New York Times and other outlets reported the news as shaking confidence into a major hypothesis about what causes Alzheimer’s and how to treat it– the amyloid hypothesis.

But not everyone agreed with that assertion. Take Nobel Laureate Paul Greengard, who told C&EN this year (subscription link) that semagacestat’s troubles may have been due to the drug’s incomplete selectivity for gamma-secretase.

This year Greengard’s team discovered a potential way to sidestep the selectivity issue, by targeting a protein that switches on gamma-secretase and steers it away from activities that can lead to side effects. Greengard thinks the amyloid hypothesis is very much alive. But the final word on the amyloid hypothesis will come from trial results in next year and beyond, for drugs such as BMS-708163, Bristol Myers Squibb’s gamma-secretase inhibitor.

11. Avandia (Barely) Hangs On

Avandia was once the top selling diabetes medication in the world, but in 2010 long-running rumblings about the drug’s cardiovascular risks reached fever pitch. By the fall, Avandia was withdrawn from the European Union market and heavily restricted in the US.

Avandia (rosiglitazone) helps diabetics control their blood sugar levels by making cells more responsive to insulin. Widespread scrutiny of Avandia dates back to 2007, when a study led by Vioxx-whistleblower and Cleveland Clinic cardiologist Steve Nissen suggested Avandia increased the risk of heart attacks. In February 2010, a leaked government report that recommended Avandia be pulled from the market made headlines. In July, an FDA advisory panel voted on what to do about Avandia, and the results were a mixed bag, with most panel members voting either to pull the drug entirely or add severe restrictions. In the end, FDA sided with the “restrict” panelists- Avandia is still on the market, but it can only be prescribed to patients who can’t control their blood sugar with a first-line medication.

Clearly, researchers still have a lot to learn about how the drugs in Avandia’s class work. But we enjoyed reading Derek Lowe’s self-characterized rant about just how much effort has been put in so far. Among several other drugs in Avandia’s class, Rezulin (troglitazone) was pulled from the market many years ago because of adverse effects on the liver, but Actos (pioglitazone) remains on the market and appears to be safe.

12. Executive Musical Chairs

The year after a trio of mega-mergers and at a time when patent losses are piling up, drug companies shook up their management. The most notable changes came at Pfizer: First, the company abandoned its two-headed approach to R&D leadership and picked Michael Dolsten, former head of R&D at Wyeth, to lead research. Martin Mackay, Pfizer’s head of R&D, meanwhile jumped ship to lead R&D at AstraZeneca. Then, in a move that took everyone by surprise, Pfizer’s CEO Jeff Kindler suddenly stepped down and Ian Reade took over. At, Merck, president Kenneth Frazier will take over as CEO in January;  Richard T. Clark will stay on as chairman of Merck’s board. And just this week, Sanofi-Aventis saidformer NIH director Elias Zerhouni would replace Marc Cluzel as head of R&D, while Merck KGaA appointed Stefan Oschmann as head of pharmaceuticals. Oschmann comes on from Merck & Co., where he was president of emerging markets.

In the biotech world, the most notable shift came in June, when George Scangos moved over from leading Exelixis totake the top job at Biogen Idec.

13. RNAi Rollercoaster

The year has been a tumultuous one for RNAi technology. Leaders in siRNA technology are experiencing growing pains as they try to turn promising science into commercialized products. Alnylam, arguably the best-known and biggest player in the RNAi arena, laid off 25% of its staff after Novartis decided not to extend its pact with Alnylam. Things only got worse when Roche announced it was exiting RNAi research, a move that hit its development partners Alnylam and Tekmira. Roche seemed to be primarily worried about delivery, an issue that is holding the field back from putting more RNAi-based therapeutics into the clinic.

But it’s not all bad news: the year brought a spate of big-ticket deals for companies developing other kinds of RNAi technology. GSK signed on to use Isis Pharmaceuticals’ antisense technology, which uses single-stranded rather than double-stranded oligonucleotides. And Sanofi entered into a pact with Regulus, the microRNA joint venture between Isis and Alnylam, worth $740 million. Further, Isis and Genzyme made some progress with mipomersen, the cholesterol drug developed using Isis’ antisense technology.

14. Revival of Interest in Cancer Metabolism

In cancer research, the old was new again in 2010, with a flurry of publications about depriving cancer cells of their energy source by taking advantage of quirks in their metabolism. That idea has been around since the 1920′s- when German biochemist Otto Warburg noticed differences in how cancer cells and normal cells deal with glucose. This year, Celgene handed over $130 million upfront for access to any cancer drugs that come out of Massachusetts biotech Agios Pharmaceuticals’ labs. One target in Agios’s crosshairs is an enzyme involved in glucose metabolism- pyruvate kinase M2. In addition to the Celgene/Agios deal, we noted that AstraZeneca and Cancer Research UK are in a three-year pact related to cancer metabolism, and the technology behind GlaxoSmithKline’s much-talked-about $720 million purchase of Sirtris has to do with depriving cells of energy.

15. More Job Cuts

Not to end this list on a sour note, but it wouldn’t be complete without acknowledging the ongoing narrative of layoffs and retooling at drug companies. This year brought brutal cuts at AstraZeneca, GSK, Bristol-Myers Squibb, and Abbott, along with the widespread and ongoing layoffs at Pfizer and Merck. Several features in C&EN looked at the impact the cuts are having on chemists:

How some laid-off pharma chemists migrate to new careers

How academic programs are adapting

And the views from the ground in New England and California, two hotbeds of pharma/biotech (hint- it ain’t pretty).

For more jobs insight, join the discussions happening with Chemjobber and Leigh aka Electron Pusher, and check out their chemistry jobs blog roundtable, which just wrapped today.

Is Pfizer After Biocon’s Insulin Portfolio?

The Economic Times is reporting that Pfizer is interested in buying the U.S. and European rights to Bangalore-based Biocon’s insulin franchise in a deal that would include a $200 million upfront payment. Rumors that Pfizer would buy Biocon’s oral insulin product emerged in August, but the specifics on a possible pricetag have caused shares of the Indian company to rise over 8%.

Biocon’s diabetes pill is in Phase III trials in India and Phase I studies in the U.S. The potential for an oral insulin product is vast, but so is the risk—getting the right balance in insulin administration is a tricky business. (Click here for my colleague Ann Thayer’s take on efforts to make inhaled or oral insulin products.) One has to wonder how much money Pfizer would be willing to pay for another alternative insulin after the colossal failure of the inhaled insulin Exubera. Low demand for the treatment prompted Pfizer to pull it from the market a year after its approval, costing the company some $5 billion after licensing fees, R&D costs, and write-offs.

To be fair, an insulin pill has been the holy grail for diabetes researchers for some time. It would be less onerous than daily injections and more discrete than the unwieldy to downright ridiculous inhaled insulin instruments.

Some background on Biocon’s technology: Biocon’s oral insulin program came from its 2006 acquisition of Nobex, a N.C.-based biotech that developed a way to make a pill form of biologics, which normally need to be given as an injection or IV infusion. Nobex used what it called “PegAlkylation” technology, which links a polyethylene glycol chain (those same PEGs used to improve the delivery of interferons and other large molecules) and an alkyl to a biologic like a protein or peptide. The design creates a molecule with a water-soluble and fat-soluble end that can travel through the myriad environments inside our bodies. Nobex claimed its oral insulin drug effectively reproduces the “first-phase spike,” or the large hit of insulin the pancreas puts out after a meal, a challenge for injectable and inhaled forms of insulin.

Pfizer wouldn’t be the first big pharma to invest in an insulin pill. GlaxoSmithKline licensed an earlier version of Nobex’s oral insulin drug, but gave back the rights in late 2003. Nobex abandoned worked on that molecule in favor of a newer and better one, which Biocon licensed in 2004, prior to its acquisition of Nobex.

Oral insulin aside, its worth noting that today’s ET story says the $200 million is for Biocon’s insulin portfolio, whereas earlier stories focused on Pfizer’s interest in the oral insulin program. European regulatory authorities recently gave the nod to allow Biocon to start Phase III trials of a biosimilar insulin, a product produced in yeast that Biocon already sells in India. Like several of its big pharma compatriots, Pfizer is making a big push into biosimilars, and was on the lookout for acquisitions that would beef up its portfolio of copycat biologics. One has to wonder whether the rumored deal would be for the whole enchilada, or just oral insulin. If the former is true, the $200 million starts to sound like a steal.

Seattle Genetics’ Brentuximab Validates ADC Approach

After years of plugging away at antibody-drug conjugates, Seattle Genetics has finally secured significant validation for its technology. This morning, Seattle-based biotech announced impressive results from a pivotal trial of brentuximab vedotin, an anti-CD30 antibody linked to an auristatin, a small molecule that blocks the formation of microtubules.

Brentuximab, also known as SGN-35, shrank or got rid of tumors in 75% of Hodgkin’s lymphoma patients who had failed to respond to other treatments. Further, that response to SGN-35 lasted for over six months in many of those patients. In this patient population, medical experts had felt that anything more than a 30% response rate would have been solid, Needham & Co. analyst Mark Monane said in a note to investors.

The results “underscore the importance of targeting CD30 in the treatment of Hodgkin’s lymphoma and provide strong validation for our proprietary antibody-drug conjugate technology,” Seattle Genetics’ CEO Clay Seagall said in a conference call this morning.

With today’s data, Seattle Genetics appears to be succeeding in an area that has proven challenging for many. In theory, designing an antibody-drug conjugate (ADC) is straightforward: tether a powerful chemotherapeutic to a cell-specific antibody that can deliver it directly to tumors. And voila, the therapeutic window is opened on chemo drugs that are excellent cancer killers but too toxic to healthy cells.

But developing an ADC has turned out to be tougher than anticipated. The biggest hurdle for scientists has been finding the right link between the antibody and the small molecule–the link after all enables scientists to control where and when that toxic payload is released. Continue reading →

China, Heparin, And Heterogeneity

The antithrombin-III binding domain of heparin illustrates the chemical variety of the drug.

Back in 2007 and 2008, tainted heparin from China was responsible for the deaths of over 80 people in the U.S. If you had some sort of warm and fuzzy reassurance that authorities were looking into the matter, a new congressional probe should quash that feeling pretty quickly. Today the Wall Street Journal reported that the probe, by two congressmen from Texas, has found that China never looked into the heparin scandal at all. This is despite repeated warnings from FDA, as C&EN wrote last year.

The probe comes ahead of FDA Commissioner Margaret Hamburg’s first trip to China in her new official capacity. The congressmen, Reps. Joe Barton and Michael Burgess, urged the commissioner to bring the issue up during her trip. According to the WSJ, a spokeswoman for China’s State Food and Drug Administration said the results of the probe were “not true.”

It’s a shame this scandal had to happen at all- all because heparin, a drug so many people rely on, is easier to harvest from a pig intestine than it is to make in the lab. Continue reading →

Safety Data On Vivus’s Qnexa Doesn’t Cut It For FDA Panel-UPDATED

You have to feel for the FDA’s Endocrinologic and Metabolic Drugs Advisory Committee this week. They’d just finished the Avandia slog, but there was no rest for the weary. No, instead, they got to sink their teeth into the first of the potential new obesity drugs, Vivus’ Qnexa.
In a vote that signals safety is king in the obesity drug realm, Qnexa got a thumbs down from the panel this afternoon. The panel was split, with 7 members recommending that FDA should approve the drug and 9 recommending against approval.

The panel’s take home message was that a lack of safety data led to their decision.

Several journalists live-blogged the panel session. Here are the two play-by-plays I followed:
Lisa LaMotta, Minyanville
Adam Feuerstein, TheStreet

This decision comes after what seemed like an optimistic week for Vivus. On Tuesday, when FDA released its briefing documents about Qnexa, media reports on the data suggested that even though the agency’s review focused on safety, it didn’t look like safety would be a dealbreaker. In a note to investors, Leerink Swann analyst Steve Yoo wrote, “Overall, we believe the language in the FDA briefing documents to be fairly benign, but the FDA is requesting a pregancy category X label that would include contraindication in pregnant women and a warning/ precaution for females of childbearing potential.”

At today’s panel, as expected, nobody really dwelled on Qnexa’s efficacy. But Vivus faced a lot of questions about safety, especially about the effects of Qnexa during a pregnancy. During clinical trials, 13 women on Qnexa gave birth, and none of the babies had birth defects. Because Qnexa is likely to be an appealing option for women of reproductive age if it’s approved, panelists were concerned that more data are needed to make sure Qnexa is safe during pregnancy. That’s because one of the components of Qnexa is topiramate, an epilepsy drug that is known to carry a risk of birth defects. What complicates things is that the dose of topiramate in Qnexa is lower than the dose used for treating epilepsy. It’s also lower than the doses used in studies that suggested topiramate carries a risk of birth defects.

The panel also discussed the other four safety concerns mentioned in the briefing documents:
cardiovascular risks
psychiatric events
cognitive events
metabolic acidosis

But at the end of the day, panelists who voted ‘no’ felt like more long-term safety data was in order. From Feuerstein’s liveblog:

one of the “no” votes says obesity is a chronic disease, so tell me what happens to patients as they stay on the medication for years.

The deadline for FDA to make a decision on Qnexa is October 28. So it might be a while before we hear the final word. Vivus has time to come up with more safety data.

Trading on Vivus’s shares was stopped today because of the hearing but will start again tomorrow. Shares for Arena and Orexigen, the other two big players in the obesity drug race, fell late today. It was a bit of a rollercoaster day for Arena, since shares soared earlier today because of new lorcaserin data published in the New England Journal of Medicine.

UPDATE July 16: Yesterday evening Vivus responded to the news in a conference call. In an accompanying press release, the company noted that “The vote from the Endocrinologic and Metabolic Drugs Advisory Committee is a recommendation. The FDA will take the Committee’s recommendation into consideration during its review of the current application and will make a determination. The FDA may or may not follow the Committee’s recommendation.”

Leland Wilson, Vivus’ CEO, said in the release “We appreciate the Advisory Committee’s recognition of obesity as a significant health crisis, and the challenges associated with the treatment of this disease.”

“We are disappointed with the Advisory Committee’s vote. While the final vote was close, and we are encouraged that the Committee recognized the efficacy demonstrated in the QNEXA clinical trials, we will work closely with the FDA leading up to our October 28, 2010 PDUFA date to address the labeling and safety questions raised during today’s proceedings. We remain committed to patients living with obesity and weight-related disease.”

Merck’s Kamarck Talks Biosimilars

Reuters has a report out today on the potential market for biosimilars, or generic versions of biologic drugs. The players will be few, and the challenges many, the report suggested.

“Access to the nascent market for so-called biosimilars, worth an estimated $10 billion (6.6 billion pounds) by 2015, will be limited to a close circle of specialist companies with the means to invest heavily and to fend off a legal onslaught, analysts said.”

Coincidentally, I sat down earlier this week with Michael Kamarck, the new head of the company’s biosimilars arm Merck Bioventures. Kamarck, who previously headed up biologics manufacturing at Wyeth, had a strikingly similar perspective on the market. He also expects few players based on a high barrier to entry. Biosimilars players will need to have technology capabilities (see Genzyme’s woes for the challenges of manufacturing biologic products), the financial mettle to conduct large clinical trials, the ability to navigate a still fuzzy regulatory pathway, and the right commercial strategy once a biosimilar is approved.

When asked about drug pricing, Kamarck noted that in markets with a limited number of players, prices tend to stabilize after an initial drop. The biosimilars approved in Europe generally cost about 70% of the innovator’s price, and he expects the U.S. market will shake out in a similar way. “We think that’s a good model and provides a fair return and a large advantage for patients,” he said.

Why so little of a discount? As the Reuters article explains, the “development, production and marketing of a copycat version of biological drugs already cost about 50 times the amount needed to launch a generic copy of conventional chemical drugs.”

However, biosimilars players could have an advantage of more cost-effective manufacturing. When asked whether he was worried about innovators simply lowering their price or selling their own biosimilars, a strategy Amgen seems prepared to pursue, Kamarck pointed to the significant improvements in yields of the mammalian cell culture lines used to make many top-selling biologics. The innovator, on the other hand, has to go through FDA to make changes to their manufacturing process. “It might well be that coming into the game now, you can make manufacturing improvements to the processes that the innovator is stuck with,” he adds.

Merck has two biosimilars, both acquired last year from Insmed, in the clinic: MK-4214 and MK-6302, generic versions of Amgen’s Neupogen and Neulasta, respectively. The company plans to  have five biosimilars in late development n 2012, though isn’t identifying which innovator medicines they will be copying. Development of MK-2578, a similar version of Amgen’s Aranesp, was abandoned earlier this year due to regulatory and market challenges for erythropoietin-stimulating agents. The drug had been considered a “biobetter” rather than a biosimilar, because it was being made using yeast-based technology rather than the same kind of cell line as Amgen’s drug.