Category D medicines are known to sometimes cause harm in humans, but they may be used in certain circumstances when the overall benefit to the mother—and, perhaps, indirectly the baby—outweighs that risk. Category X medications are known to cause harm to a developing human embryo or fetus, and their risks outweigh any potential benefit to the mother.
Because of these risks, clinical trials involving investigational medications routinely exclude pregnant women from study. Only women who are incapable of pregnancy (e.g. postmenopausal or surgically sterilized) or, in some cases, potentially fertile but using effective birth control are typically included in these trials.
As a postscript to the serious harm it caused, further research found that thalidomide is actually helpful for some diseases. In 1998 the FDA approved it for treatment of erythema nodosum leprosum, a painful skin problem associated with leprosy, and in 2006 for treating multiple myeloma, a cancer involving a type of blood cell called a plasma cell. Of course, thalidomide remains in Category X, and its use is tightly regulated.
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Nothing Ever Comes Easy
Clinical medical research has other limitations. It's not unusual for two or more large research studies investigating the same new medication or device to produce contradictory results. For example, one study may show a study medication is significantly better than placebo while another study doesn't find that to be so. Clinical trials typically exclude patients at the extremes of age (e.g. children), unless the trial is aimed specifically at those age ranges. Patients who have significant kidney or liver disease, cancer, or other serious medical problems in addition to the disease an investigational medication is designed to treat may also be excluded from trials due to these patients potentially having increased risk and decreased benefit from using that medicine. Individuals who participate in trials are also self-selected, in that they must agree to participate and give informed consent for treatment and follow-up.
Funding for clinical trials comes from many sources. These sponsors include government agencies such as the National Institutes of Health and Department of Veterans Affairs, as well as private medical institutions and foundations. Many trials are also sponsored by companies that make pharmaceuticals and medical devices. When a promising new class of medication or type of medical device is identified, these different companies often vie with each other to produce better versions. Sometimes this results in development of new medications and treatments that truly are improvements on older ones. However, it can also result in “me too” medicines being approved for use—new drugs that are medically not definitely better than the previous “gold standard” or each other, but which can cost significantly more than older, less expensive alternatives.
Economic, legal, and other nonmedical issues may also influence medical research. Pharmaceutical companies play an important role in developing new medicines and devices to improve medical care. However, questions have been raised about whether the results of unfavorable research concerning new or approved medications have been suppressed or at least argued against by them in ways that don't seem to make patient safety and well-being the most important considerations.[18] Also, these companies may not consider finding new treatments for rare diseases as being intrinsically profitable, thus delaying or curtailing research in those areas. Financial incentives for developing these so-called “orphan drugs” may include subsidies from governments, foundations, and other sources, as well as tax credits and special patent and marketing rights.
On the other hand, these companies can also suffer major financial losses due to product liability issues whose scientific validity is questionable at best. While these controversies are too complex to detail here, perceived adverse effects from vaccines and silicone-gel-filled breast implants have resulted in lawsuits against the manufacturers. For example, Dow Corning, a major manufacturer of silicone breast implants, filed for bankruptcy in 1995 due to lawsuits claiming that its products were responsible for an increased risk of adverse events, including breast cancer and other diseases. Subsequent studies found no significant association between silicone breast implants and those medical problems.[19]
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Future Directions
The landscape of basic and clinical medical research is constantly shifting. Medications and other products that are currently approved undergo continued reappraisal regarding their uses and safety. Many medicines have significant “off-label” uses—indications that are not officially approved by the FDA, but are considered appropriate based on other research and clinical practice. Many new ways to diagnose and treat diseases continue to be evaluated. While some may turn out to be dead ends or need much more work before they're routinely available, others appear particularly promising for improving medical care in the near future.
For example, medical care individualized to a particular person's genotype—"genomic” or “personalized” medicine—has the potential to significantly increase the ratio between benefit and risk of using available medications. There is variability among individuals regarding the presence of certain genes that predispose or protect against certain diseases, or that influence how the body metabolizes and responds to medications for good or ill. Genetic profiling can help identify which medicines would be most beneficial and least likely to harm a particular individual. This would potentially be a significant improvement to the heuristic and probabilistic methods physicians employ based on known average risks and benefits for patients in general.
But every silver lining has a cloud. There's the potential risk that employers, insurance companies, or governments could use that genetic information against people who have a genetic predisposition to diseases and who therefore may be more “costly” regarding their medical care. For the individual, knowing he or she is susceptible to certain health problems can be beneficial if this information leads to improved prevention or treatment. It might also be more information than a person wants to know if the disease or other problem in question is one that's currently impossible to prevent or cure.
Stem cell research has a tremendous potential to help repair or replace damaged parts of the body. Adult stem cells are currently used for bone marrow transplantation in patients with leukemia. Embryonic and adult stem cells could someday also be used to routinely treat neurological diseases such as Alzheimer's dementia and Parkinson's disease, as well as diabetes and many other problems.[20] Preliminary studies indicate that stem cells derived from a person's bone marrow could be used to improve heart function following a myocardial infarction.[21]
The field of nanomedicine is in its infancy. Nanotechnology involves manipulating and using materials at the scale of individual atoms and molecules, at a size measured at the nanometer (1 x 10-9 meter) level.[22] Potential uses include production of drug delivery systems, biosensors, identification of cancer cells, or even nanoscale machines to repair the components of cells directly.
Overall, nanomedicine is still at a basic research stage, with its full “real life” benefits and risks still to be determined. Medicines produced using nanotechnology that are currently approved for use include more effective, nanoparticle preparations of certain anti-cancer medications, such as Doxil (doxorubicin) and Abraxane (paclitaxel). Zinc oxide nanoparticles are also used in products such as sunscreen, deodorants, and foot powder.[23]
Gene therapy offers the potential for treating inherited genetic diseases and certain cancers. Clinical research has focused on individuals with single genetic defects that produce debilitating and potentially life- threatening illnesses. Examples include severe combined immunodeficiency (SCID), which produces marked vulnerability to infections; adrenoleukodystrophy, which damages the brain and adrenal glands; and Leber's congenital amaurosis, which causes severe visual impairment or blindness.[24]
One common technique for gene therapy is to introduce a “normal” version of a defective gene into a patient's cells using a particular “vector.” For example, a virus such as an adenoviru
s or retrovirus can be genetically modified to remove any disease-causing genes and include the desired, normal gene for the individual's genetic abnormality. After the modified virus is injected, it “infects” the person's cells and incorporates the “good” gene into that individual's DNA so that the cells now function normally—thus treating the underlying disease.
Both basic and clinical research studies are examining ways to improve the safety and efficacy of gene therapy.[25] A major setback occurred in 1999 when an eighteen-year-old patient with ornithine transcarbamylase deficiency, a genetic disease that damages the nervous system and liver, died during a clinical trial soon after he was injected with a modified adenovirus. Further, using gene therapy to not just treat diseases but to also improve a “normal” person's genome remains a possibility, but one fraught with serious scientific and ethical issues before it becomes reality.
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The Long and Winding Road
As with other scientific endeavors, medical research doesn't follow a straight line from ignorance to enlightenment. Every success story is the result of some combination of inspiration, study, and hard work. Despite the best efforts to minimize them, there have been and will be missteps, dead ends, and even tragedies along the way. But the goal of helping us live longer, healthier lives is worth the effort.
Copyright © 2010 H.G. Stratmann
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1 Masia N. “The Cost of Developing a New Drug. In: Focus on Intellectual Property Rights: U.S. Department of State;” 2006. p. 82-83. www.america.gov/st/econ-english/2008/April/20080429230904myleen0.5233981.html
2 Waldo AL, Camm AJ, deRuyter H, Friedman PL, MacNeil DJ, Pauls JF, et al. Effect of d-sotalol on mortality in patients with left ventricular dysfunction after recent and remote myocardial infarction. The SWORD Investigators. Survival With Oral d-Sotalol. Lancet 1996;348(9019):7-12.
3 Pratt CM, Camm AJ, Cooper W, Friedman PL, MacNeil DJ, Moulton KM, et al. “Mortality in the Survival With Oral D-sotalol (SWORD) trial: why did patients die?” Am J Cardiol 1998;81(7):869-76.
4 Echt DS, Liebson PR, Mitchell LB, Peters RW, Obias-Manno D, Barker AH, et al. “Mortality and morbidity in patients receiving encainide, flecainide, or placebo. The Cardiac Arrhythmia Suppression Trial.” N Engl J Med 1991;324(12):781-8.
5 Greene HL, Roden DM, Katz RJ, Woosley RL, Salerno DM, Henthorn RW. The Cardiac Arrhythmia Suppression Trial: first CAST . . . then CAST-II. J Am Coll Cardiol 1992;19(5):894-8.
6 “Effect of the antiarrhythmic agent moricizine on survival after myocardial infarction.” The Cardiac Arrhythmia Suppression Trial II Investigators. N Engl J Med 1992;327(4):227-33.
7 Effect of prophylactic amiodarone on mortality after acute myocardial infarction and in congestive heart failure: meta-analysis of individual data from 6500 patients in randomized trials. Amiodarone Trials Meta-Analysis Investigators. Lancet 1997;350(9089):1417-24.
8 Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA, 3rd, Freedman RA, Gettes LS, et al. ACC/AHA/HRS 2008 “Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines.” Circulation 2008;117(21):2820-40.
9 Silverstein FE, Faich G, Goldstein JL, Simon LS, Pincus T, Whelton A, et al. “Gastrointestinal toxicity with celecoxib vs. nonsteroidal anti-inflammatory drugs for osteoarthritis and rheumatoid arthritis: the CLASS study: A randomized controlled trial.” Celecoxib Long-term Arthritis Safety Study. JAMA 2000;284(10):1247-55.
10 Bombardier C, Laine L, Reicin A, Shapiro D, Burgos-Vargas R, Davis B, et al. “Comparison of upper gastrointestinal toxicity of rofecoxib and naproxen in patients with rheumatoid arthritis. VIGOR Study Group.” N Engl J Med 2000;343(21):1520-8.
11 Antman EM, Bennett JS, Daugherty A, Furberg C, Roberts H, Taubert KA. “Use of nonsteroidal anti-inflammatory drugs: an update for clinicians: a scientific statement from the American Heart Association.” Circulation 2007;115(12):1634-42.
12 Sachdev M, Miller WC, Ryan T, Jollis JG. “Effect of fenfluramine-derivative diet pills on cardiac valves: a meta-analysis of observational studies.” Am Heart J 2002;144(6):1065-73.
13 Fishman AP. “Aminorex to fen/phen: an epidemic foretold.” Circulation 1999;99(1):156-61.
14 Manson JE, Hsia J, Johnson KC, Rossouw JE, Assaf AR, Lasser NL, et al. “Estrogen plus progestin and the risk of coronary heart disease.” N Engl J Med 2003;349(6):523-34.
15 Hendrix SL, Wassertheil-Smoller S, Johnson KC, Howard BV, Kooperberg C, Rossouw JE, et al. “Effects of conjugated equine estrogen on stroke in the Women's Health Initiative.” Circulation 2006;113(20):2425-34.
16 Mosca L, Banka CL, Benjamin EJ, Berra K, Bushnell C, Dolor RJ, et al. “Evidence-based guidelines for cardiovascular disease prevention in women: 2007 update.” Circulation 2007;115(11):1481-501.
17 Silverman WA. “The schizophrenic career of a “monster drug.” Pediatrics 2002;110(2 Pt 1):404-6.
18 Vedula SS, Bero L, Scherer RW, Dickersin K. Outcome reporting in industry-sponsored trials of gabapentin for off-label use. N Engl J Med 2009;361(20):1963-71.
19 McLaughlin JK, Lipworth L, Murphy DK, Walker PS. “The safety of silicone gel-filled breast implants: a review of the epidemiologic evidence.” Ann Plast Surg 2007;59(5):569-80.
20 Lenzer J. “The Super Cell.” Discover 2009(September):30-36.
21 Gersh BJ, Simari RD, Behfar A, Terzic CM, Terzic A. “Cardiac cell repair therapy: a clinical perspective.” Mayo Clin Proc 2009;84(10):876-92.
22 Lerner EM. “Follow the Nanobrick Road.” Analog Science Fiction and Fact 2008;128(9):38-48.
23 Jain KK. The Handbook of Nanomedicine. Humana Press, Totowa, NJ. 2008.
24 Naldini L. Medicine. "A comeback for gene therapy.” Science 2009;326(5954):805-6.
25 Gene Therapy. In: Human Genome Project Information. A brief description of the current status of gene therapy. www.ornl.gov/hgmis/medicine/genetherapy.html
[Back to Table of Contents]
Novelette: PUPA by David D. Levine
Extreme circumstances can require radical departures from even the most deeply rooted “traditons. . . ."
A spasm of pain made Ksho drop her forelimb-brush.
Xinecotic-ki Ksho always ached all over, from her mandibles to the tips of her third pair of limbs. Pain and hunger were the natural states of a Shacuthi juvenile—pain from constant rapid growth and hunger for the vast quantities of food she needed to sustain that growth—but this latest spasm was the bone-deep ache that meant her skin was getting to be too small. She had already molted seven times and knew this feeling well, but this next molt would be her last as a juvenile. After this molt she would pupate for three months, her ugly juvenile body replaced by a gleaming adult.
She was thrilled. She was terrified.
But for now, she had a job to do.
Ksho bent down and scrabbled with clumsy, weak two-fingered hands for the brush on the rough cloth of the floor, wishing she had an adult's hands—gleaming three-fingered structures of chitin and bone, capable of powerful grasp and fine manipulation. Finally, using both of her first pair of hands, she managed to regain the brush and resumed her laborious progress to her parent Xinecotic's grooming chamber, waddling along on stumpy little hind limbs barely capable of supporting her growing weight.
The delay probably saved her life.
Ksho did not scrape at the door before entering the grooming chamber. The scraping-board was for adults; juveniles came and went as their duties required, with no more notice or need for permission than the air that cooled the corridor. She paused for a moment with one hand on the door latch, making sure she had a firm grip on the brush, and at that moment she heard voices from within.
The unexpected sound made Ksho freeze, her skin tingling—an instinctive response honed over thousands of generations. Surely there could be no other adult in Xinecotic's grooming chamber at this hour? The hour of grooming was inviolate, a time of quiet contempla
tion. But life had been strange ever since they had traveled to this cold and desolate place, and it had only become stranger in the last few months. Ksho worked the lower door latch, slid the door open a crack, and poked one eye into the room.
Xinecotic was not alone in her grooming chamber. Takacha, the head of the expedition, was there as well. Neither adult took any notice of Ksho's eye peeping around the door's edge. Ten or twelve of Ksho's sisters were also present, buffing and polishing their parent's gleaming limbs and torso. None of them seemed to be alarmed by Takacha's presence in Xinecotic's grooming chamber, but Ksho told herself she shouldn't expect her younger siblings to be as observant as she. She was the eldest, after all, nearly ready to pupate.
"You should have realized,” Takacha was saying, “that you wouldn't be able to maintain this deception forever.” As she spoke, a flavor of apprehension drifted through the slightly open door to Ksho's fingers. Both adults were nervous, verging on terrified. Why?
"Don't do this, Takacha.” Xinecotic was holding perfectly still, most unlike the usual rolling and preening of an adult being groomed. “You can stop this madness now, before any permanent harm is done. I'm authorized to offer clemency if you halt the operation immediately and surrender."
Takacha chuttered, antennae lifting, as though Xinecotic had just said something funny. “Clemency.” She raised one hand, and Ksho's already sour stomachs soured still further, with fear, as she realized Takacha held a weapon leveled at Xinecotic's thorax. That explained her parent's unnatural immobility. “You'll have to offer far more than that to make abandoning this operation worthwhile."
One of Ksho's sisters ran out of grooming-wax and headed toward the wall niche for more. Neither adult paid her any heed. “Think, Takacha. What you've done so far is only a level-three offense, but harming an agent of the Grand Nest means death by suffocation. And if I don't check in, there will be an investigation."
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