An observational study from Ireland shows the consequences of abruptly stopping alpha-1 antitrypsin (AAT) substitution therapy:

In February 2017, the Irish Health Authority decided against reimbursing AAT replacement therapy. In the preceding years, some Irish patients with alpha-1 antitrypsin deficiency (AATD) had participated in the RAPID and RAPID-OLE trials and continued to receive AAT treatment beyond the study period (through an extension agreement with the manufacturer). At the beginning of 2017, the manufacturer negotiated with the Irish Health Authority to secure future public funding for these patients' therapy. As no agreement was reached, treatment was discontinued in September 2017 for 19 patients with severe AATD. Up to that point, they had received intravenous AAT at a dose of 60 mg per kg of body weight for an average of 8-10 years.
By mid-December 2017 (approximately 77 days after discontinuing therapy), two of the 19 patients had already died from a severe exacerbation (disease flare-up). Comparing the patients' data – now without substitution therapy – to the corresponding period the previous year with substitution therapy, the average exacerbation rate was increased (approximately one more exacerbation per patient). The number of hospitalizations also rose, and various inflammatory markers in the blood were significantly elevated.
The Irish Alpha1 patient organization presented the results of the observational study to the authorities and an agreement was reached regarding cost coverage by the authorities and the manufacturer for the 17 patients.
According to the ug publication, these observations suggest that abruptly stopping alpha-1 antitrypsin substitution therapy after a prolonged treatment period can have serious health consequences for the patient.
We understand the concerns of every patient who is reluctant to visit a doctor's office for their iodine replacement therapy during the Covid-19 pandemic, but this study shows that a prolonged interruption of treatment is not a sensible alternative. Therefore, we strongly encourage you to discuss with your doctor which form of continued treatment might be appropriate for you. Consider the options of home and self-infusion as well.

Summary by Marion Wilkens.
Note: Unfortunately, this article Oliver J McElvaney et al., N Engl J Med 2020; 382:1478-1480 Accessible only with an existing subscription to the New England Journal of Medicine.

We received a further comment from our advisory board member Prof. Sabina Janciauskiene on this matter:

Consequences of abrupt discontinuation of alpha-1 antitrypsin replacement therapy – Reply to the editor:

The goal of augmentation therapy with human plasma alpha-1 antitrypsin (AAT) is to slow the progression of pulmonary emphysema in patients with inherited AAT deficiency. This treatment is continued throughout the patient's life. The letter by McElvaney et al. (April 9 issue) 1) provides important evidence that discontinuing this long-term therapy is associated with poorer health outcomes, including more frequent exacerbations. Lung transplantation (LuTx) is the last treatment option for patients with AAT deficiency who develop end-stage lung disease. In most clinical centers, the use of augmentation after LuTx is not recommended. However, in patients who received augmentation prior to LuTx, withdrawal of this therapy may have adverse effects. Data from the Transplant Center at Hannover Medical School show that 10-year survival rates for patients who received AAT therapy prior to lung transplantation are 50% worse than for patients who were never treated.² In general, survival rates for lung transplant recipients with AAT deficiency are similar to those for other forms of chronic obstructive pulmonary disease.^3,4 The consequences of augmentation withdrawal under different clinical situations must be carefully considered.

Since the publication of their article, the authors have reported no further potential conflicts of interest.

Authors: Sabina Janciauskiene-Wandmarke, Jan Fuge, Sabine Wrenger, Thomas Fühner, Tobias Welte

References
1) McElvaney OJ, Carroll TP, Franciosi AN, Sweeney J, Hobbs BD, Kowlessar V, Gunaratnam C, Reeves EP, McElvaney NG. Consequences of Abrupt Cessation of Alpha1-Antitrypsin Replacement Therapy. N Engl J Med. 2020 Apr 9;382(15):1478-1480. doi: 10.1056/NEJMc1915484
2) Eur Respir J. 2017 Sep 10:50(3). pii: 1700962. doi: 10.1183/13993003.00962-2017.
3) Banga A, Gildea T, Rajeswaran J, Rokadia H, Blackstone EH, Stoller JK. The natural history of lung function after lung transplantation for alpha(1)-antitrypsin deficiency. Am J Respir Crit Care Med. 2014:190(3):274-281.
4) Transpl. Int. 2018 Jan;31(1):45-55. doi: 10.1111/tri.13038