Cancer breakthroughs often get their first airing at the annual meeting of the American Society of Clinical Oncology. This year’s meeting was no exception.

One finding getting a lot of press has its origins in a pair of studies in Nature in 2005. The studies showed how to selectively kill cancer cells deficient in BRCA1 and BRCA2, genes that are mutated in some of the deadliest breast and ovarian cancers.

The agent that does the killing is called a PARP inhibitor. And trial results released last week show some pretty promising results.

Olaparib, a PARP inhibitor under development by AstraZeneca PLC, shrank tumors in more than a third of women whose breast cancers had BRCA mutations. The trial did not have a control arm, but the data look encouraging, considering the agent was given alone, without other drugs, and that the subjects had already had an average of 3 chemotherapy regimens. A similar trial showed that the drug could also shrink advanced ovarian tumors in subjects with BRCA1 or BRCA2 mutations.

A truer test of whether a drug is likely to help patients is whether it can prolong survival. A randomized, controlled trial of BS1-201, under development by Sanofi-Aventis SA, examined this question in 116 women with some pretty nasty tumors: their breast cancer had metastasized to other parts of their body and was ‘triple negative’, meaning it lacked receptors on their tumors for estrogen, progesterone and HER2, each of which are targets for current therapies. The drug prolonged survival by three and a half months, to 9.2 months, when added to a standard chemotherapy regimen.

Bigger studies are needed, but the findings so far validate a concept with deep origins in basic research. BRCA1 and BRCA2 facilitate DNA repair, a function that emerged after years of painstaking research. PARP (poly(ADP)-ribose polymerase) mediates DNA repair also, but in a distinct way. The Nature studies exposed cells lacking BRCA1 or BRCA2 to PARP inhibitors and showed that these cells get nailed: their DNA is such a fragmented mess that they die.

Mice deficient in PARP are viable, fertile and tumor-free, which bodes well for the side effect profile of these drugs. Subjects who received the drugs reported only mild side effects, including nausea and fatigue.

Other highlights at ASCO include promising findings with multikinase inhibitors, which can block several types of proteins that go astray in tumor cells. Cancer vaccine approaches also got a boost with positive findings from trials in melanoma and non-Hodgkin’s lymphoma.

Posted by Charlotte Schubert at 12:16 PM | Permalink | Comments (2)

Swine flu is entering the mixing bowl. The virus that emerged this spring in Mexico is now reaching the place where it may have its greatest potential to mutate—the tropics. Cases have recently been identified in India, Vietnam and the Philippines.

Flu viruses circulate year-round in tropical regions, where they can mix with each other, mutate and spawn new strains. Two studies published last year outlined this process, showing how seasonal flu strains in the temperate regions originate in tropical regions.

Unfortunately, as Declan Butler at Nature reports, surveillance networks are often weak in tropical countries, so it may be difficult to monitor the evolutionary trajectory of the new H1N1 virus.

Vaccine experts breathed a sigh of relief when the first sequences of the new H1N1 virus revealed relatively little variability among isolates. That makes it easier for manufacturers to produce a vaccine that could work against all forms of the virus. But the virus may surprise us in the fall, popping up as a different sort of beast—or beasts.

There are also fears that the virus will wreak havoc in sub-Saharan Africa, where there are many people living with HIV, weakening their immune system and possibly increasing their vulnerability to swine flu.

Posted by Charlotte Schubert at 02:43 PM | Permalink | Comments (1)

Normally I'm bored to tears reading articles about our broken health care system in the United States and how to fix it. I'd almost rather rememorize the steps of glucose metabolism--the absolutely worst part of being a biology major.

But finally someone has made the subect readable--that expert at medical prose, Atul Gawande. His article in the latest issue of the New Yorker is an insightful read.

He takes us on a tour of McAllen, Texas, the town with the most expensive health care system in the country. Here, it seems, doctors routinely send patients to surgery who might not need it. Doctors have financial relationships, some legal, some apparently not, with hospitals and other institutions that do surgery, imaging and testing. It all has the effect of funneling money into doctors' wallets and ramping up the costs for Medicare, the primary payer in the county.

In contrast, he notes that the famous Mayo Clinic provides much less expensive care. The incentives in this system, and others like it, are set up so that doctors focus more on the patient; they spend more time with them, they consult more with specialists in other fields, and perform fewer unecessary procedures. The result is not only less expense, but radically better patient care.

As the debate on health care ramps up this summer, I'm happy that there are some people out there who devour policy papers on health care like it's candy. For them, this might be old news. For the rest of us, Gawande makes it come alive.

Posted by Charlotte Schubert at 01:39 PM | Permalink | Comments (0)