From Medscape Medical News
March 3, 2010 (New Orleans, Louisiana) — Children with asthma who continue to have symptoms while using low-dose inhaled corticosteroids (ICS) can benefit from "stepping up" treatment by increasing the dosage or adding either a long-acting beta agonist (LABA) or a leukotriene-receptor antagonist (LTRA), according to a new triple-crossover randomized study called BADGER (Best Add-On Therapy Giving Effective Responses).
In fact, 98% of the study participants showed a significant improvement in asthma control after the addition of at least 1 of these options, according to research presented here at the American Academy of Allergy, Asthma and Immunology (AAAAI) 2010Annual Meeting and published online simultaneously in The New England Journal of Medicine.
Although the overall best response was achieved by adding a LABA, many of the children had a best response with one of the other step-up treatments, "highlighting the need to regularly monitor and appropriately adjust each child's asthma therapy,"
He added that factors such as baseline Asthma Control Test (ACT) score, the absence of eczema, and race might also help clinicians to "better predict which of the 3 treatment options will help a patient the most."
Past Step-Up Evidence Lacking
Although clinicians usually agree on treatments going from step 1 (intermittent asthma) to step 2 (persistent), the few studies that have been conducted on how to best treat children whose asthma is poorly controlled while receiving low-dose ICS have shown inconsistent results, reported Dr. Lemanske.
"The evidence to guide step-up therapy is lacking," he told Medscape Allergy and Clinical Immunology. "So we wanted to answer the question: What is the best way to go from step 2 to step 3?"
Researchers from 5 centers (in 4 states), making up the National Heart, Lung, and Blood Institute–funded Childhood Asthma Research and Education Network, worked on the BADGER trial.
They sought to conduct a comparison study to establish not only which step-up therapy was best, but also "whether there are phenotypic or genotypic characteristics that can be used to predict whether a child will have a better response to one particular treatment than to another."
A total of 498 children between the ages of 6 and 17 years with mild to moderate asthma were enrolled between March 2007 and July 2008, with 157 (65.4% male; mean age, 10.8 years) receiving each of the 3 step-up treatments in random order for 16 weeks each.
These treatments were the standard low-dose ICS (100 µg of fluticasone twice daily) plus either the LABA salmeterol (50 µg twice daily) or the LTRA montelukast (5 or 10 mg daily), or 2.5 times the standard ICS dose (250 µg fluticasone twice daily) only. Each patient also received a metered-dose inhaler of albuterol and prednisone.
At the end of each 16-week period, the number of days that the asthma symptoms were under control, lung function, and the number of exacerbations and attacks were measured before the patient moved on to the next treatment option.
Methods used included the Pediatric Asthma Quality of Life Questionnaire, the ACT (with scores from 0 to 27), spirometry tests, and patient- or guardian-recorded diary entries.
A Place for All 3 Therapies
The results, concentrating on the 165 patients who completed at least 2 study periods, showed that "although our goal was for 25% of the patients to see a difference in their asthma symptoms after using at least 1 of the treatments, we were surprised to see that 161 showed substantial improvement [P < .001]," said Dr. Lemanske.
The best response was shown in almost 40% of the patients by adding the LABA, in 30% by adding the LTRA, and in 28% by increasing the dose of ICS.
Using rank-ordered logistic regression, the predicted response to the LABA addition was significantly better than to the addition of the LTRA (relative probability [RP], 1.6; 95% confidence interval [CI], 1.1 - 2.3; P = 0.004) and the ICS step-up (RP, 1.7; 95% CI, 1.2 - 2.4; P = .002).
"In other words, the LABA was more than one and a half times as likely to produce the best response," explained Dr. Lemanske.
"All 3 therapies clearly have a place in the management of kids with persistent asthma not well controlled on low-dose [ICS] alone," said investigational team member Leonard B. Bacharier, MD, from the Department of Pediatrics at Washington University in St. Louis, Missouri, in a press release. "Statistically, LABA therapy was most likely to help the most patients, but it's hard to look at an individual patient and know which one to choose."
Significant predictor factors included ACT score, eczema, and race.
LABA treatment was the best add-on therapy for patients with an ACT score greater than 19 (P = .009). However, "if it was 19 or under, there was no difference among the therapies in producing a differential response," reported Dr. Bacharier.
Although patients who had eczema did well on any of the 3 treatments, those who did not have eczema did better on the LABA.
The LABA was also most likely to give the best response in whites. The LABA and higher-dose ICS were equally likely to show the best response in African Americans, whereas the LTRA was least likely.
Factors that were not found to be significantly predictive of a drug's effectiveness included age, sex, allergies, bronchodilator response or reversibility, and number of recent exacerbations.
Dr. Lemanske said that although he was disappointed to not find more predictors, "we're not done analyzing and still have lots of genotyping to do."
A Ceiling Effect for Low-Dose ICS
"Overall, our findings suggest that there is a ceiling effect of low-dose [ICS] in many, though not all, children, and that the addition of a different class of medication is often required to achieve improvements in asthma control," said Dr. Lemanske. "The important take-home message is that if you choose something at step 3 and you're not happy with it, based on the control, instead of pushing it up to step 4, look to one of these other treatments."
He noted, however, that none of the study treatments provided perfect asthma control, and that there were still 120 asthma exacerbations or attacks among the patients who required rescue medication with prednisone. "We obviously still need to do more work."
When asked about the recent mandates of the US Food and Drug Administration (FDA) on the need to lower the use of LABAs in patients with controlled asthma, Dr. Lemanske said that that was like comparing apples and oranges.
"The FDA was talking about step-down treatment, and our study was on step-up therapy for patients who did not have control of their asthma. Also, BADGER was an efficacy trial and we were not powered to look at safety outcomes. The duration of our trial and the size of our sample precluded statements regarding long-term risks."
In the journal article, the authors write that "clinicians who prescribe LABAs (never to be used as monotherapy) in combination with [ICS] should continue to evaluate risk-benefit ratios."
N Engl J Med. Published online March 2, 2010.