Asthma is a common pathology, with a prevalence of 6 to 8% and more than 4 million patients in France. Its management is based on different therapeutic axes. Their use is very dependent on disease control, with therapeutic escalation, from treatment on demand to a combination of them at high dosage, according to the severe asthma's phenotype.

Despite these effective therapeutic tools, there is a lack of control of the disease in the vast majority of cases, affecting at least 60% of asthmatics. Among the factors associated with lack of control, non-compliance with inhaled therapies is frequent and requires to be systematically assessed in the absence of control.

Its evaluation by definition is complex and variously appreciated, fluctuating from 40 to 80%. The means proposed for evaluating it involve doctor/patient interviews, evaluation of the therapeutic response, questionnaires, evaluation of drug consumption (evaluation of number of empty boxes, integrated electronic device, withdrawal of drugs from pharmacies, etc).

Asthma control is commonly evaluated using the validated Asthma Control Test score, in clinical practice and/or in research fields. An ACT score greater than 20 indicates well-controlled asthma. In addition, a change of at least 3 points is likely to indicate a clinically meaningful change in asthma control (Minimally Clinical Important Difference) in an individual patient over time and a change of 4 points or more further reduces the risk that the change is due to measurement error.

In the context of severe eosinophilic asthma, Mepolizumab has shown its benefit in controlling asthma, reducing the number of exacerbations and its ability to decrease the use of oral corticosteroids (MENSA, SIRIUS).

Mepolizumab is now available in 2 new "ready-to-use" forms: a pre-filled syringe and an auto-injector pen. Both systems can be administered at home either by a nurse or by the patient himself (self-administration). The choice is left to the discretion of the prescribing pulmonologist.

These new possibilities of Mepolizumab administration offer greater freedom to the patient, possibly allowing him to empower himself by carrying out his own treatment, without constraint and without being dependent on the availability of a nurse or another healthcare professional qualified to inject Mepolizumab.

These new methods of Mepolizumab self- administration also open the field to therapeutic non-compliance, a new problem in the field of biotherapies used for the treatment of severe asthma.

The investigator hypothesize a potential therapeutic non-compliance associated with the new method of administration of Mepolizumab, with self-injection by the patient, without the assistance of a nurse.

To assess this problem, the investigator propose to compare in a therapeutic trial Mepolizumab administered by pre-filled syringe by a home nurse every month versus Mepolizumab self-administered by auto-injector pen by the patient every month.

Inclusion Criteria:

1. Patient aged ≥ 18 years
2. Severe asthma diagnosed by a pulmonologist and followed for at least a year
3. Blood eosinophilia ≥ 0.15 G / L in the 12 months preceding inclusion in the trial.
4. At least 2 exacerbations in the past 12 months, each time treated with oral corticosteroid therapy or an increase in dosage of oral corticosteroid therapy prescribed for a long time, for at least 72 hours.
5. High dose inhaled corticosteroid therapy (> 800 μg / d budesonide,> 500 μg / d fluticasone,> 1000 μg / d beclometasone, etc.) and at least one second controller asthma treatment with Long-Acting Beta-Agonists or Long-Acting Muscarinic Antagonists
6. Patient must have an efficient contraception method
7. Patient affiliated to a social security scheme.
8. Patient able to give free, informed and written consent.

Exclusion Criteria:

1. Pregnant woman (urinary beta-HCG positive at inclusion) or breastfeeding
2. Active smoking or ex-smoking for less than 6 months and more than 10 pack-years
3. Exacerbation in the 4 weeks preceding first Mepolizumab injection
4. Patient who has already been treated with Mepolizumab or another anti-IL-5 or -5R treatment
5. Patient currently using a biotherapy indicated in severe asthma other than anti-IL5 or 5R treatments or stopped for less than 2 months
6. Treatment underway with another biotherapy not indicated for severe asthma
7. Patient participating in other interventional research, excluding routine care research (old regulation) and category 2 research not interfering with primary endpoint analysis
8. Other chronic respiratory pathology (bronchiectasis, chronic obstructive pulmonary disease, pulmonary fibrosis, etc.)
9. Any other uncontrolled chronic pathology, the presence of which would be considered incompatible with the performance of the study by the investigator
10. Patient under guardianship, curatorship or legal protection