TNF antagonists and UC

In my fellowship (15 years ago), the use of thiopurines (eg. azathioprine, 6-mercaptopurine) for ulcerative colitis was debated.  Many physicians urged colectomy rather than using these drugs which could have long-term consequences.  At the time, the risk of thiopurines was less well-understood.  Over time, the use of these agents has become common when mesalamine products were ineffective.  The same issue comes up with TNF antagonists versus colectomy.

A recent study provides more information on the effectiveness of adalimumab for patients with moderate-to-severe UC but does not settle this debate (Gastroenterology 2012; 142: 257-65).  In this study, termed ‘ULTRA-2’ (Ulcerative colitis long-term remission and maintenance with adalimumab 2), the  efficacy of adalimumab for induction & maintenance of remission was studied in 494 patients.  This was a randomized, double-blind, placebo-controlled study; average age was 40 years.

Clinical remission in the adalimumab group were 16.5% at 8 weeks (9.3% placebo).  At 52 weeks, 17.3% in the adalimumab group were in remission (8.5% placebo).  Among patients naive to anti-TNF agents, the response rate was 21.3% at week 8 & 22% at week 52.  Safety overall was similar in both groups; however, in the adalimumab group one patient developed gastric cancer and one developed squamous cell carcinoma.

The authors conclude that adalimumab is safe and more effective than placebo in inducing and maintaining remission among patients with moderate-to-severe UC.

A second study, also published this past month, looks at the use of infliximab for maintenance therapy for UC (Inflamm Bowel Dis 2012; 18: 201-11).  Patients who had achieved benefit from ACT-1 and ACT-2 studies were followed for three years.  Dosage of infliximab could be adjusted.  A total of 229 patients entered the study.  During the study, 70 patients (30.6%) discontinued infliximab due to adverse effects (10.5%), lack of efficacy (4.8%) or other reasons (15.2%); the majority were able to continue infliximab.  The authors indicate that no new safety issues were identified. Yet, there were two deaths among the infliximab group including a 19 year-old nonsmoker who developed lung cancer and a lethal case of histoplasmosis.

Because the improvement compared to placebo is modest with both of these agents, the question about whether to use these medications or proceed to surgery in UC patients is unanswered.

Additional references:

  • -Aliment Pharmacol Ther. 2008 Oct 15;28(8):966-72. Epub 2008 Jul 24.  Long-term outcome of adalimumab therapy for ulcerative colitis with intolerance or lost response to infliximab: a single-centre experience.
  • -Am J Gastroenterol (Oussalah A et al) 2010; 105: 2617-25. Multicenter study of IFX for UC
  • -Gastroenterology 2010; 138: 2282. Severe pediatric UC. 25/33 responded to IFX. colectomy rate 19% at 1 year.
  • -Gastroenterology 2009; 137: 1204 (ed), 1250. lower colectomy rates at 54wks in IFX vs placebo (+concomitant meds): 10% vs. 17%.
  • -Clin Gastro & Hep 2008; 6: 1112. Do NOT use CYA post infliximab and vice versa. n=19. 1 death due to sepsis. Remission rates occur in ~1/3rd but are of short duration.
  • -NEJM 2005; 2462. 69% clinical response @ 8 weeks (vs. 37% placebo) & 45% at week 54 (vs. 20% placebo).
  • -JPGN 2004; 38: 298. 82% short-term response, 63% sustained response; n=16.

Methotrexate and liver toxicity

There are drawbacks with all of the therapies for inflammatory bowel disease; however, usually the inflammatory bowel disease is worse than any of the medications. One of the therapies that  has started to see increased usage in Crohn’s disease is methotrexate (MTX), both as an alternative to thiopurines and as an adjunct to Remicade.  There are a number of side effects; a patient handout is available at the following: http://www.ccdhc.org/diseases/MethotrexateLetter.pdf

One of the concerns with MTX has been liver toxicity, in part because of descriptions in the rheumatology literature with long-term usage.  In Crohn’s disease patients, it appears that the risk is much lower (Inflamm Bowel Dis 2012; 18: 359-67).  This study found 13 trials for their meta-analysis.  A total of 632 participants were included: 373 MTX, 131 thiopurines, 128 placebo.  In the MTX group, elevated hepatic aminotransferases occurred in 1.4 per 100 person-months.  The rate of elevation more than 2-fold the upper limit of normal was 0.9 per 100 person-months.  Thus, of the initial 373 patients, 39 had an abnormal aminotransferase.  26 of these 39 had spontaneous resolution, 3 improved with dose reduction & 10 withdrew from MTX treatment (0.8 per 100 person-months).  Seven of these withdrawals were from one of the earlier studies (Feagan et al. NEJM 1995; 332: 292-97). Besides the low likelihood of needing to stop MTX due to liver toxicity, the other observation was that the liver toxicity was mostly dependent on the dose; therefore, dosage reduction would likely be effective if needed.

In my practice, when considering MTX treatment, I usually recommend the following:

  • Monitoring: Baseline: CXR, CBC, Amylase, Renal, LFTs, urine HCG & then Q2-4 weeks initially, then Q3months
  • Give Folate during therapy.
  • Use zofran if needed for nausea
  • Avoid NSAIDs during treatment due to renal toxicity
  • Contraindicated with pregnancy (MTX=teratogen) -females should see gynecology
  • Families warned in writing that this medication is given once a week; more often can be deadly

Additional references:

  • -IBD 2011; 17: 2521. ~25% remission at 1yr, 16% at 2yrs.. n=93.
  • -JPGN 2011;53: 389. n=64. Supports use of zofran for 1st few months to prevent nausea.
  • -JPGN 2010; 51: 714. Use of MTX after thiopurines. n=27. 48% in remission at 6 months.
  • -JPGN 2009; 48: 526. Use in pediatric CD, n=25. 64% response
  • -JPGN 2009; 48 suppl 2: S111. MTX may be effective for UC.
  • -NEJM 2008; 359: 2790. Similar safety of AZA and MTX in vasculitis patients. AZA may be safer.
  • -IBD 2008; 14: 756. MTX in Crohn’s. n=39. 71% remission (20% steroid-free).
  • -J Clin Pharm & Therapeutics 2007; 32: 327-31.
  • -Am J Health Syst Pharm 2004; 61: 1380-84. review of MTX errors -FDA reported
  • http://www.npsa.nhs.uk/patientsafety/alerrts-and-directives/alerts/oral-methotrexate/
  • -Am J Gastro 2007; 102: 2804-2812. n=60 pediatric patients. ~42% in remission with MTX & ~50% improved. 13% (8) had to stop due to increased LFTs or sepsis.
  • -IBD 2006; 12: 1053. n=61. MTX for AZA nonresponders/breakthroughs: 80% with improvement/ 45% with long-term response; 10% discontinued due to side effects. Steroids stopped in 36.
  • -JPGN 2005; 40: 445. Oral MTX works as well as IM/SC.
  • -JPGN 2003; 37: 392 (194A) 0.4 mg/kg/weekly. 91% response at 2 mo, most still needed remicade
  • -Gastroenterology 2003; 124: suppl 1, A-41 (305) 11/12 responded – able to stop remicade
  • -Feagan et al. NEJM 1995; 332: 292-97.
  • -J Pediatr 1999: 134: 47. Hepatotoxic risk factors. (enzymes & obesity). Consider bx if serial enzymes increased >40% of the time over 1 year
  • -Arthritis Rheum 1997; 40: 2226.

More imaging needed?

With new tools at our disposal in diagnosing inflammatory bowel disease, we need to decide how and when to use them.  Potential new modalities include stool inflammatory markers, video capsule endoscopy, CT enterography (CTE), and MR enterography (MRE).  Several studies have shown that the information that these studies yield may change management. The latest of these studies (Inflamm Bowel Dis 2012; 18: 219-25) looked at how the knowledge of CTE effected management and physician confidence with Crohn’s disease.

The authors prospectively assessed 273 patients with established or suspected Crohn’s disease.  In their analysis, 70 patients (48%) of established cases had altered management because of CTE and 69 (54%) of suspected cases.  These changes were considered to be  independent of clinical, serological or histologic findings.  Changes included medication modification in 45 (16.2%), excluding Crohn’s disease in 46 (16.8%), surgery referral in 10 (3.7%), alternate diagnosis established in 9 (3.2%), & canceling surgery in 7 (2.6%).  The authors considered excluding active small disease as an important management plan change; this occurred in 18 patients (6.6%).

The authors state that their current practice is to use MRE for serial imaging rather than CTE, to minimize risks from radiation; though CTE is often the initial imaging.

My take on this article is that information from imaging often increases the certainty about the diagnosis and gives a more complete picture of the severity.  It is likely that more information leads to more aggressive therapy.  At the same time, in pediatric gastroenterology, the trend towards using more effective therapy earlier in the course of the disease has developed even in the absence of extensive imaging (see previous: Only one chance to make first impression).  Whether more imaging in pediatric patients would be worthwhile is not known.

Additional references:

  • -JPGN 2008; 47: 31.  Capsule endoscopy may reclassify pediatric IBD
  • -NEJM 2010; 363: 1, 4. Safety of CT. Can have overdose of radiation and even standard doses could cause complications. Also, a big issue is downstream unnecessary testing due to incidental findings.
  • -Clin Gastro 2008; 6:283. Use of CT enterography.
  • -JPGN 2010; 51: 603.  MRE for suspected IBD.  Useful in Crohn’s disease.
  • -IBD 2004;10: 278-285.  WCE for Crohn’s (review)  Capsule can help differentiate UC from Crohn’s.

Food as medicine

Two recent articles add some useful information regarding enteral therapy for Crohn’s disease (Inflamm Bowel Dis 2012; 18: 246-53 & JPGN 2012; 54: 298-305).

The first article enrolled 34 children with newly-diagnosed Crohn’s disease.  Patients were divided into elemental and polymeric formula groups and followed in a prospective, double-blind randomized controlled trial for two years.  Measures of improvement included the PCDAI as well as fecal calprotectin and fatty acids.  Both groups of patients responded clinically.  93% (14/15) of the elemental formula group achieved remission based on PCDAI scores (<11) and 79% (15/19) of the polymeric formula group.  The initial treatment was use of formula (along with only clears) either by NG or oral for 6 weeks.  All patients had NG placed at time of endoscopy and if sufficient oral intake was demonstrated (for 2 days), NG was removed.  All subjects had small bowel and colonic disease.  Although calprotectin levels decreased, they remained very elevated.  In the EF group, the median calprotectin dropped from 2023 μ/g to 1113 μ/g, though only one patient had a level below 400; similarly in the PF group the calprotectin dropped from 1929 μ/g to 1134 μ/g, and only two patients had a level below 400.  Some to the reasons why changes in diet may be useful have been alluded to in a previous post: Eat your veggies…if you don’t want to get sick.

The second reference is a clinical guideline on the use of exclusive enteral nutrition EEN).  The introduction notes that 65% of European pediatric gastroenterologists use EEN compared to 4% for North American pediatric gastroenterologists.  In pediatric trials, EEN and corticosteroids were considered ‘equally effective’ in a pediatric meta-analysis which included five randomized controlled trials (n=147).  However, a Cochrane review favored corticosteroid treatment over EEN in a meta-analysis that included adult and pediatric patients (n=192 EEN, n=160 corticosteroids).  According to the authors, small studies have demonstrated other potential advantages of EEN including higher rates of mucosal healing and better linear growth.  With regard to mucosal healing, the initial cited study casts with ongoing elevated calprotectin indicates that this does not occur in the majority of children with EEN therapy.  Other caveats:

  • Disease location: some evidence favors small bowel disease rather than colonic disease
  • Formula composition: does not seem to matter whether elemental or polymeric
  • Duration of therapy: majority treat for 6-8 weeks of EEN.  The authors recommend at least 8 weeks
  • Time for response: Inflammatory markers improve in a little as a week, remission typically 2-4 weeks
  • Concomitant medications: many places initiate immunomodulator treatment; others cycle EEN
  • Start with goal 120% of ‘maintenance’ nutrient needs.  On 1st day, authors recommend starting at 1/2 goal volume and gradually increase over 1-2 days
  • Partial enteral nutrition (PEN) (eg. overnight feedings & normal daytime diet) has been helpful in improving growth and may improve remission rates.
Why not EEN or PEN? Potential barriers include cost, difficulty changing diet, fear of tube feedings, and more acceptable alternatives.  At the same time, some of these barriers could be overcome.  Quality of life measures have improved in children receiving enteral nutrition.

The use of more top-down therapy may affect all of the above considerations (Only one chance to make first impression).

Additional references:

  • -Cochrane Database Syst Rev 2007; CD000542.  Enteral nutritional therapy vs corticosteroids to induce remission in Crohn’s disease.
  • -Gastroenterology 2011; 141: 742. AGA guidelines on use of enteral nutrition in wide variety of conditions.
  • -Gastroenterology 2008; 135 : 1005. omega-3 fatty acids ineffective in Crohn’s dz for maintaining remission.
  • -Pediatr Res 2007; 61: 356-60.  Enteral nutrition effect on protein turnover in adolescents with Crohn’s disease.
  • -J Pediatr 2000; 136: 285-91. Nutritional Rx w polymeric diet is effective w/in 8 weeks in 32/37.
  • -Scand J Gastro 2001; 36: 383-8. Elemental & polymeric diets successful in maintaining remission in ~43% of adults with complete steroid withdrawal
  • -JPEN 1992; 16: 499. improved wt,ht, decreased prednisone, decreased CDAI
  • -JPGN 2000; 31 (supp 2) A291. Polymeric vs elemental diet.
  • -JPGN 2002; 35: 339-40. Lactase deficiency – same prevalence in IBD as in RAP.
  • -JPGN 2000; 31: 3 & 8. EN about as effective as steroids for primary Rx.

Can I go?

How safe is it for IBD patients to travel?  A retrospective study from adult patients with IBD (n=222) compared with controls (n=224) indicates that the risk of travel for IBD patients is only a little more than the general population (Clin Gastroenterol Hepatol 2012; 10: 160-65).

IBD patients with an average age of 37 years had infections during 15% of trips compared with 11% for controls.  92% of infections were due to enteric disease. However, this increased risk was identified in travel to industrialized countries not to developing countries.  This likely indicates that much of the increase is due to IBD flares rather than increased susceptibility to infections.  Nearly half of patients in this study were receiving immunosuppression: immunomodulators 29%, biologics 5%, dual therapy 6%, or corticosteroids 4%.  Not surprisingly, patients with increased IBD flares (OR 1.9) and IBD-related hospitalizations (OR 3.5) represent a group with higher risk for illness.  Most illnesses were mild & self-resolving in a few days.  Only five IBD patients required hospitalization for the following: dehydration, perianal abscess, malaria, flare, & small bowel obstruction).

Additional references:

  • -Clin Gastro & Hep 2010; 8: 490. Review of traveler’s diarrhea. Recs pepto if emesis, rifaximin or cipro or azithromycin if watery diarrhea, azithromycin if bloody diarrhea
  • -Clin Gastro & Hep 2007; 5: 451. Use of rifaximin (200mg tid)-loperamide provided rapid improvement.
  • -NEJM 2006; 354; 119. Traveler’s diarrhea.
  • -NEJM 2002; 347: 505.  Illness after travel.
  • -www.cdc.gov/travel/index.htm

Speed matters

Capsule endoscopy is cool.  Like any technology, it has certain advantages and some shortcomings.  Understanding that this technology has limited sensitivity and specificity is an important matter in clinical practice.

The suboptimal sensitivity is apparent in a recent study (Am J Gastroenterology, (10 January 2012) | doi:10.1038/ajg.2011.461).  In this study titled, “Detection of Lesions During Capsule Endoscopy: Physician Performance Is Disappointing,” the authors compare the performance of 17 capsule endoscopists in reading clips from 24 capsule procedures.  18 of these clips were abnormal but only abnormal in <0.1% of frames.  They compared different reading modes, speeds and the experience of the physicians.  By using clips, they were able to truncate the sessions to a similar length as an individual capsule procedure.

Their findings showed detection rates of 69% for angioectasias, 38% for ulcers/erosions, 46% for masses/polyps, and 17% for blood.  For all categories the detection rate was ~45% for SingleView15, QuadView20, and QuadView30; however, SingleView25 had a 25% detection rate.  One surprising finding was how little experience mattered; there was no significant advantage in having more experience.  In fact, the best performer who correctly identified 78% of the abnormalities had read only 45 capsule studies previously; the worst performer with a 17% score had read more than 11,000 previously.

In a typical capsule study, 40,000-60,000 images are generated.  If there is not a diffuse disease, then the lesion may go undetected.  The findings of these studies, though limited by the small number of interpreting physicians, confirm problems with sensitivity from other studies.  One aspect of this study that deserves emphasis is that speed matters.  As with colonoscopy, additional time reviewing the study does increase the likelihood of identifying abnormalities.  Ultimately, technological innovation may improve the results with capsule endoscopy.  With newer versions of the software,  “suspected blood indicator” (SBI) quickly identified six of the 18 lesions and “QuickView” identified 11 of the 18 lesions.  As with any test, though, if the clinical suspicion is high, having another physician review the study or using an alternative imaging tool may be necessary.

Another problem to keep in mind with capsule endoscopy (or wireless capsule endoscopy -WCE) is that especially in adults there is a significant background abnormality rate that may be clinically unrelated (Clin Gastro & Hepatol 2005; 3: 133-141. n=413. 13.8% with baseline mucosal injury).

Additional references:

  • -IBD 2008; 14: 1219. Correlation of capsule & MRI enteroclysis. Capsule detected more mucosal lesions.
  • -JPGN 2008; 47: 31. Capsule endoscopy may reclassify pediatric IBD.
  • -Dig Liver Dis 2008; 40: 216-223. Study comparing capsule vs EGD in detecting varices.
  • -JPGN 2008; 46:4. Review.
  • -Gastroenterology 2007; 132: 855. Capsule outperforms push enteroscopy.
  • -IBD 2007; 13: 331. Role of WCE in IBD.
  • -Pediatrics 2006; 118: e904. Use of capsule endoscopy for HSP
  • -Clin Gastro & Hep 2005; 3: 959. WCE should be 2nd step in obscure bleed, p egd/col.
  • -Clin Gastro & Hep 2005; 3: 772. WCE outperforms enteroclysis in identifying Crohn’s sm bwl dz.
  • -Gastroenterology 2005; 128: 1172. NSAID injury witnessed in 68% of healthy volunteers p 2 week course; 75% c increased fecal calprotectin.
  • -Clin Gastro & Hepatol 2005; 3: 411. Practical applications & review.
  • -Clin Gastro & Hepatol 2005; 3: 264-70. Study of 30 children; helpful in diagnosing obscure bleeding.
  • -Endoscopy 2005; 37: 960-65. Results of capsule endoscopy trials
  • -Clin Gastro & Hepatol 2005; 3: 133-141. WCE to assess NSAID injury, n=413. 13.8% with baseline mucosal injury. Celebrex with fewer lesions than Naproxen plus omeprazole.
  • -Gortzak Y, Lantsberg L, Odes HS. Video capsule entrapped in a Meckel’s diverticulum. J Clin Gastro 2003; 37: 270-271.
  • -Clin Gastro & Hep 2005; 3: 55. visible lesions c NSAIDs
  • -IBD 2004;10: 278-285. WCE for Crohn’s (review) Capsule can help differentiate UC from Crohn’s.
  • -Clin Gastro & Hepatology 2004; 2:xx. Dx of Peutz-Jeghers w WCE.
  • -Gastro 2004; 126: 643-653. WCE performs well for occult bleeding, especially active bleeding (87% detection rate)
  • -Clinical Gastro & Hepatology 2004; 2: 14-15, 31-40.
  • -Gastroenterology 2003; 124 (suppl 1) A37. abnl small bowel findings common in healthy subjects.
  • -JPGN 2003; 37: 332 (18A), n=58. Crohn’s, polyposis, occult bleeding
  • -Gastroenterology  2003; 124: suppl 1, A-37 (284) 22% of normal pts c abnl wireless findings
  • -Gastroenterology  2002; 123: 999-1005, 1385-88. capsule is superior to radiographs for suspected small bowel dz.
  • -Gastro Endosc 2002; 56: 452-456. Algorithm suggests using this modality if negative upper & lower endoscopy & no acute overt bleeding. If capsule endoscopy is negative & patient is stable, observation appropriate.
  • -Gastro Endosc 2002; 56: 621-24. ASGE guidelines.

Add it to the list

A recent review article (NEJM 2012; 366: 158-64) describes a common, chronic recurrent granulomatous inflammatory disease that manifests as painful, deep-seated inflamed lesions (including sinus tracts and abscesses); it typically starts after puberty.  This disease is due in part to aberrant healing processes and impaired mechanical integrity. Investigations have shown that tumor necrosis factor α is involved in the pathogenesis of hidradenitis suppurativa.  There are a lot of similarities between hidradenitis suppurativa and Crohn’s disease as well as some overlap as up to 17% of individuals with Crohn’s disease have hidradenitis suppurativa.  In addition, hidradenitis suppurativa can be confused with Crohn’s disease especially when buttocks/perianal lesions are present.

Key clinical points with this disease:

  • Affects skin with apocrine glands
  • Long delay in diagnosis is common though disorder may affect 1% of population
  • Incision and drainage is not effective treatment –lesions recur
  • Few randomized studies –most often treated with combination of antibiotics (eg. clindamycin & rifampin)
  • More severe disease may benefit from TNF inhibitors or possibly complete surgical excision
For pediatric gastroenterologists, hidradenitis suppurative is another to add to the Crohn’s differential diagnosis list:
 

Infectious etiologies: 

Histoplasma , Amebiasis, CMV, C. diff, Klebsiella oxytoca, Actinomycosis, HIV

Noninfectious etiologies:

Sarcoidosis, Vasculitis (HSP,dermatomyositis, Wegener’s, SLE), FMF, allergic colitis, Hirschsprung’s, autoimmune enteropathy, Chronic granulomatous disease, glycogen storage dz, 1B, Hermansky-Pudlak syndrome, Wiskott Aldrich syndrome, NEMO (NF-kB essential modifier) deficiency, Leukocyte adhesion deficiency, SCID, Behcet’s, FELS/hemophagocytic lymphohistiocytosis, Typhlitis

Additional reference for hidradenitis suppurativa:

  • -Br J Dermatol 2010; 162: 195-7.

Crohn’s Disease and differential diagnosis -references:

  • -JPGN 2010; 51: 690. Discusses sarcoid (check angiotensin converting enzyme), CGD, Hermansky Pudlak
  • -JPGN 2010; 50: 99. Perianal dz in young children may be due to autoimmune neutropenia.
  • -IBD 2008; 14: 1443. Phagocyte dysfunction. Also, discusses Hermansky-Pudlak, GSD 1B, chronic granulomatous disease, Chediak-Higashi, leukocyte adhesion deficiency, cylic neutropenia, congenital neutropenia
  • -JPGN 2006; 42: 405. Vasculitis mimicking IBD.
  • -NEJM 2005; 352: 489-94.
  • -J Clin Gastroenterol 1992; 15: 17-23.
  • -NEJM 2003; 349 (26): 2541-49.  Table 2. (Gold et al.)

When nothing else is working

The situation when “nothing else is working” comes up with a number of pediatric gastroenterology phenotypes, including inflammatory bowel disease, encopresis, and functional abdominal pain.  With severe refractory Crohn’s disease, the use of Thalidomide has been explored (JPGN 2012; 54: 28-33).  In this recent description of 12 refractory patients (three females), followed over an average of 4.6 years, thalidomide was associated with improvement in many outcome measures.  All patients were refractory to multiple other medical therapies (particularly infliximab and adalimumab).  Five of seven patients with fistulas had complete resolution, Harvey-Bradshaw index improved (11.8–>3.9), steroid dependency improved (daily dose 13.9–>2.3mg/day), sedimentation rate improved (35–>14), and both hospitalizations & surgeries decreased.

However, 42% developed peripheral neuropathy and adverse reactions resulted in discontinuation in nine of the patients.  The peripheral neuropathy developed on average 43 months into treatment (range 12-79 months) and clinically resolved in all patients within 2-3 months after discontinuation.  All patients enrolled participated in close monitoring as required by the FDA STEPS program —system of thalidomide education and prescribing safety.

Additional references:

  • -JPGN 2003; 37: 522, UK experience. 4/6 developed peripheral neuropathy.
  • -J Pediatr 2004; 145: 856. use for JRA
  • -JPGN 2001; 32: 322-25. Irreversible neuropathy noted in patient after 9 months of Rx.
  • -JPGN 1999; 28: 214.  Response w/in one month
  • -Pediatrics 1999; 103: 1295. (in Behcet’s)
  • -Gastroenterology 1999; 117: 1271 & 1278.  22 men c refractory Crohn’s, dosed @ 200mg qhs: 9 clinical remission & 16 c response. 12 steroid-dependent men @50 or 100mg qhs: 44% off steroids over 12 weeks.
  • -JPGN 2000; 31 (supp 2) A611. Dose 1.5-2mg/kg/day in 5 males.