ARIAD Presents PACE Data; Provides Potential Gleevec Backup
Dec15

ARIAD Presents PACE Data; Provides Potential Gleevec Backup

Sufferers of chronic myeloid leukemia (CML), a rare and tough-to-treat blood cancer, received some good news at the 2011 American Society of Hematology meeting in San Diego this week. On Monday, ARIAD Pharmaceuticals disclosed new results from the Phase 2 PACE trial of its lead drug ponatinib (AP24534). The data (covered by FierceBiotech, Xconomy, and TheStreet), indicate major responses to the drug in ~40% of recipients, even in advanced or refractory (resistant to treatment) CML . With these numbers in hand, ARIAD enters a tight race, already populated by headliners like Gleevec (imatinib), which in 2001 made a splash as a first-line CML therapy. Drugs such as Gleevec and ponatinib belong to the family of tyrosine kinase (TK) inhibitors, which dock with a mutated protein called Bcr-Abl. This protein (actually a fusion of two distinct proteins via a chromosomal mishap) triggers disease by accelerating blood cell creation, leading to uncontrolled growth and eventually CML. Since cancers constantly evolve, new mutations in the TK active site had rendered Gleevec ineffective for certain variations of CML. Many of the PACE trial patients had previously tried newer TK inhibitors, such as Sprycel (dasatinib, BMS) and Tasigna (nilotinib, Novartis), and found that their CML had become resistant due to a single amino acid mutation in the kinase active site, which swapped a polar residue (threonine) for a carbon chain (isoleucine). So, ARIAD chemists decided to develop a drug that borrowed the best points from the earlier therapies, but capitalized on this mutation (A pertinent review in Nature Chemical Biology covers early examples of “personalized” cancer drugs developed for disease variants). So, how did they accomplish this particular act of molecular kung-fu?  For that, we hit up the literature and go all the way back to . . . 2010. As explained in a development round-up (J. Med. Chem., 2010, 53, 4701), most approved Bcr-Abl inhibitors share several traits: densely-packed nitrogen heterocycles linked to a toluyl (methyl-phenyl) amide, then a highly polar end group, such as piperazine or imidazole. Since the mutation axed a threonine residue, the hydrogen-bond donor adjacent to the ring in earlier drugs was no longer necessary. So, chemists replaced it with a vinyl group. A computer analysis designed to achieve better binding and drug-like properties suggested an alkyne linker might fit into the mutated active site even better than a vinyl group, so that’s ultimately what ARIAD installed. The program also suggested moving an exocyclic amino group into the aromatic (forming an uncommon imiadzo-[1,2-b]-pyridazine, green in picture). Borrowing the best stuff from other therapies, ARIAD’s chemists also wove in the “flipped” amide and -CF3 motifs (both blue) from nilotinib, as well as the methylpiperazine...

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Using Gene Expression Patterns to Repurpose Drugs
Nov14

Using Gene Expression Patterns to Repurpose Drugs

Late last month, researchers from many different fields gathered at the Computer History Museum in Mountain View, California, to discuss the benefits of open science and data sharing. One of the best talks from that event, the Open Science Summit, was delivered by Joel Dudley, the co-founder of NuMedii, a firm that aims to find new indications for medications. Dudley has repeatedly found new uses for old drugs by picking through public data sets about the gene expression profiles of different diseases. He then looks for medications that are known to reverse those profiles. Much of the data that Dudley uses comes from the Gene Expression Omnibus, which he regards as a gold mine. Life Sciences in the Era of Big Data from Open Science Summit on FORA.tv A full list of videos from the Open Science Summit is also...

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Mergers’ Latest Stint In The Hot Seat

Anyone who reads the comments at Derek Lowe’s In the Pipeline knows that drug company mergers are far from favorites among industry researchers. Mergers also took the heat at a pair of high-profile events this month. At this month’s ACS/Société de Chimie Industrielle panel discussion, former Pfizer Global R&D President John LaMattina laid the blame for ailing pharma pipelines largely on mergers. From today’s C&EN editorial by Rudy Baum: LaMattina’s comments focused on the negative impact of mergers and acquisitions on pharmaceutical R&D (Nature, DOI: 10.1038/nrd3514) calling them “a major factor in the decline in R&D productivity.” He pointed out that the Pharmaceutical Research & Manufacturers of America had 42 members in 1988, of which only 11 exist today as independent companies. While there are more than 11 current members of PhRMA, “the fact is , due to industry consolidation as well as some companies dropping their pharmaceutical R&D, there is far less competition in this industry than there was a decade ago.” “Lilly has announced that they are going to be growing organically, and not through M&A,” Baum says. At the Société event both LaMattina and fellow panelist Ron Breslow of Columbia wished the company well in this strategy, he adds. LaMattina confirms this, adding via Twitter “I would hope that Pharmas can succeed without the devastating effects of mergers.” It wasn’t just LaMattina and Breslow calling out mergers. Last Friday, at the Pharmaceutical Strategic Alliances Conference, Bristol Myers Squibb CEO Lamberto Andreotti said that avoiding mergers was part of what’s made his company successful. As tweeted by Pearl Freier, founder of advisory firm Cambridge BioPartners: PearlF: #PSA11 BMS transform, CEO credits continuity in R+D team working together for 7,8 years + No big mergers in 15 yrs, no disruptions You can read more about Andreotti’s remarks at...

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LaMattina & Breslow to Talk Future of Pharma

We wanted to point Haystack readers to an upcoming event hosted in conjunction with our parent organization, the American Chemical Society, and Société de Chemie Industrielle: On September 14, our own Rudy Baum will moderate a panel discussion between former Pfizer R&D head John LaMattina and Columbia University chemistry professor Ron Breslow. The topic? “New Business Paradigms for Pharmaceutical Companies.” If the lively discussion today on twitter over the arrival of the “niche blockbuster” (or as Chemjobber coined “nichebuster”) model for pharma is any indication, folks are pretty interested in how drug firms are going to survive in a post-blockbuster era. For those living in the NY/NJ area, you can witness what is sure to be some great banter in person; for everyone else, feel free to sign up for the...

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BMS-AstraZeneca Dapagliflozin Diabetes Drug Falls Short; Pfizer’s Answer on the Horizon?
Jul29

BMS-AstraZeneca Dapagliflozin Diabetes Drug Falls Short; Pfizer’s Answer on the Horizon?

As reported by Nature News and Forbes’ The Medicine Show  on July 20, dapagliflozin, a BMS-developed diabetes drug marketed with partner AstraZeneca, was given a “thumbs-down” by an FDA review panel on July 19. After the 9-6 final vote, panel members commented favorably on the drug’s new mechanism, but evidently felt that the safety profile could not be overlooked: the FDA committee meeting statement mentions increased risk of breast and bladder cancer, increased genital infections, and perhaps most seriously, potential for drug-induced liver injury (DILI). Dapagliflozin has been one of the rising stars of the new class of Sodium-Glucose cotransporter 2 (SGLT2) inhibitors for diabetes treatment, whose development roster includes Johnson & Johnson, Astellas, Boehringer Ingelheim, Roche, GSK, and Lexicon (Note: see Nat. Rev. Drug Disc. 2010, 551 for a full recap).  The excitement behind these drugs comes from a relatively new idea for diabetes treatment: inhibition of the SGLT2 enzyme stops the kidney from reabsorbing sugar, leading to excretion of the excess glucose in the urine, which in turn lowers blood sugar. Dapagliflozin, like most SGLT2 inhibitors, is a glucose molecule with a large aromatic group attached to the carbon atom in the spot chemists call the anomeric position. Such so-called C-glycosides are thought to have improved staying power in the bloodstream relative to O-glycosides (where the linkage point is at an oxygen atom, a more common scenario in sugars), since they are less susceptible to enzymatic breakdown. So, how do you improve these compounds? A paper Pfizer published last March (J. Med. Chem. 2011, 2952) may offer some hope.  Pfizer noted that some of the C-glycoside SGLT2 inhibitors gave a positive micronucleus test, indicating their potential to damage chromosomes. To work around this liability, their chemists  designed an analog of dapagliflozin where a second hydroxymethyl (CH2-OH) group is “tied” underneath the ring, forming a bicyclic compound that advantageously rigidifies the compound, increasing potency, while at the same time blocking a potential site of reactive metabolite formation (which might contribute to further DILI). The improved compound shows high potency for SGLT2 (~920 pm), a negative micronucleus test, and is now in Phase II  trials. Want to hear more? The lead author of Pfizer’s paper, Dr. Vincent Mascitti, will speak about the study as part of the Organic Division program at the ACS National Meeting in Denver – Sunday, August 28, 8:00 AM-8:30AM, Four Seasons...

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Sensible Antisense RNA Modifications
Jun23

Sensible Antisense RNA Modifications

This is the first Haystack post from C&EN Intern Aaron Rowe. You may recognize Aaron from Twitter (@soychemist) or from his contributions to WIRED and its science blog. Isis Pharmaceuticals showed off its latest strategy for improving the potency and pharmacokinetics of antisense oligonucleotides at its annual shareholder meeting, held last week. Their structure, called cET (structure at bottom right), should bring the size of a dose down to 5-40 mg per week and allow oral delivery of antisense molecules for some diseases. In its drugs, Isis uses a mix of several different modifications. They call these molecules gapmers. For instance, its cholesterol-lowering phase 3 compound, mipomersen (molecular model at top), has 2’-methoxyethyl modifications on each end (see structure at bottom left) and central DNA region, and it also has a phosphorothioate backbone. The newer cEt modification will be featured in a cancer drug that targets STAT3, a transcription factor that is overactive in many different malignancies. Here’s more on the cET...

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