SLIT efficacy and safety - Twitter summary from Canadian Society of Allergy and Clinical Immunology 2012 meeting

Dr. Linda Cox discussed sublingual immunotherapy (SLIT) efficacy and safety:

The global allergen immunotherapy (AIT) sales reached $835 M in 2006; about 8% of the total allergic rhinitis market. In Italy 80% of IT is SLIT. France has the 2nd highest proportion of SLIT users.

Comparison of SLIT vs. SCIT

A meta-analysis compared SCIT and SLIT: SCIT reduces symptoms by 0.73; SLIT 0.42; Medication scores -0.57 for SCIT, -0.47 for SLIT. Radulovic et al Cochrane updated meta-analysis in 2011: SLIT now performs closer to SCIT but SCIT still better.

Nasal steroids (INCS) usually have an effect size of -0.49; again SCIT -0.7, SLIT -0.45 in the same- meta analysis.

Asthma scores were reduced by -0.5 for SCIT -0.3 for SLIT.

There is a lot of heterogeneity in the SLIT studies, which makes the meta-analysis process more challenging. One major pitfall of SLIT studies is that placebo arm is not well-blinded because there are no oral itching side effect with placebo.

Symptom score reductions with grass SLIT products (all comers, tablets and drops) is usually 30% reduction compared to placebo.

Oralair (SLIT for Grass)

Oralair (SLIT Grass tablet) the 1st SLIT product in North America. Oralair (SLIT for Grass) was approved by Health Canada in the summer of 2012. Oralair is distributed by Paladin Labs in Canada - 5 grass pollen tablet - 300 IR (about 25 mcg of Phl p 5). Approved for pre and co-seasonal administration. In the studies, the efficacy for Oralair was greater among patients from areas where disease severity was the highest in local pollen season.

A recent study showed that Oralair did not benefit those who did not have detectable timothy grass specific IgE at baseline. There is a lots of discussion re: clinical application of this finding - do we need to measure sp IgE to grass prior to prescribing grass SLIT?

The Vienna Challenge Chamber Study of Oralair showed onset of action 1 month post treatment initiation but better efficacy at 4 month post-treatment.

A recent study by Greer Labs showed efficacy for ragweed SLIT, must have 43 mcg major allergen but there was a 43% reduction in symptoms.

Efficacy of Timothy grass allergy sublingual immunotherapy tablet: 37% symptoms reduction relative to placebo http://buff.ly/1G20dYB

Q &A about SLIT

Question re: use of SLIT drops vs. tablets - Dr. Cox confirms that tablets have more consistent responses in trials. Dr. Cox cautions against the off-label use of SLIT drops in North America. You can not take data from one allergen SLIT trial and directly apply it to a different allergen SLIT formulation.

Most SLIT adverse events occur within the first few weeks then fade within a month. There were 2 cases of anaphylaxis described with the first dose of a SLIT tablet.

Dr. Cox recommends that SLIT should only be prescribed by allergy-trained physicians; there is a debate as to need for epinephrine autoinjector.

Useful references:

Comprehensive review of SLIT by Bousquet, Cox, Durham etc. Allergy 2009; 64: Suppl 91: 1-59.
WAO position paper on SLIT - Canonica et al. Allergy 2009; 64: Suppl 91: 1-59.
House dust mite SLIT - Compalati et al Allergy 2009; 64: 1570-9 - Meta-analysis of HDM SLIT studies.

Twitter summary made possible by @allergydoc4kidz @DrAnneEllis @IgECPD4

Three allergists did a great job posting updates from the 2012 meeting of the Canadian Society of Allergy and Clinical Immunology (#CSACI): @allergydoc4kidz @DrAnneEllis @IgECPD4. Compared to year 2011, this represents 300% growth in Twitter use by the Canadian allergists. The AAAAI has a larger audience and not surprisingly 30 allergists posted Twitter updates from the 2012 #AAAAI meeting. I used the website “All My Tweets” to review the updated from each allergist, for example: http://www.allmytweets.net/#@IgECPD4

For comparison, here are the tweets from the 2011 #CSACI meeting: http://allergynotes.blogspot.com/search/label/CSACI