Perceptions on Home-Administration of Biologics in the Context of Severe Asthma: An International Qualitative Study

BACKGROUND

Biologics are an effective therapy for severe asthma. Home administration of biologics by patients is likely to facilitate their accessibility. Yet little is known about patients' and health care providers' (HCPs) perceptions regarding home administration of biologics.

OBJECTIVE

The aim of this study is to create more insight into the perceptions and experiences of patients and HCPs regarding home administration of biologics in the context of the treatment of severe asthma.

METHODS

A qualitative international study was performed in the Netherlands, United States, Australia, and United Kingdom. In each country, 2 focus groups were held with potential/recent and long-term users of biologics at home. Prior to the focus groups, patients were prompted with themes on online forums. For triangulation purposes, interviews were held with HCPs to discuss salient findings from forums and focus groups. Data were analyzed with qualitative content analysis.

RESULTS

In total, 75 patients participated in the forums, of which 40 participated in the focus groups. Furthermore, 12 HCPs were interviewed. The following overarching themes were identified: living with severe asthma; practical aspects of using biologics; the role of HCPs regarding biologics; social support from family, friends, and others; effectiveness of biologics and other treatments; side effects of biologics.

CONCLUSIONS

This study showed that, for those using biologics for severe asthma, the benefits of home administration of biologics usually outweigh inconvenience and side effects. Guided practice, accessible support contact, and monitoring including social support should be central in the transition from hospital to home administration of asthma biologics.

Exogenous phospholipase D generates lysophosphatidic acid and activates Ras, Rho and Ca2+ signaling pathways

BACKGROUND

Phospholipase D (PLD) hydrolyzes phospholipids to generate phosphatidic acid (PA) and a free headgroup. PLDs occur as both intracellular and secreted forms; the latter can act as potent virulence factors. Exogenous PLD has growth-factor-like properties, in that it induces proto-oncogene transcription, mitogenesis and cytoskeletal changes in target cells. The underlying mechanism is unknown, although it is generally assumed that PLD action is mediated by PA serving as a putative second messenger.

RESULTS

In quiescent fibroblasts, exogenous PLD (from Streptomyces chromofuscus) stimulated accumulation of the GTP-bound form of Ras, activation of mitogen-activated protein (MAP) kinase and DNA synthesis, through the pertussis-toxin-sensitive inhibitory G protein Gi. Furthermore, PLD mimicked bioactive lysophospholipids (but not PA) in inducing Ca2+ mobilization, membrane depolarization and Rho-mediated neurite retraction. PLD action was mediated by Iysophosphatidic acid (LPA) derived from Iysophosphatidylcholine acting on cognate G-protein-coupled LPA receptor(s). There was no evidence for the involvement of PA in mediating the effects of exogenous PLD.

CONCLUSIONS

Our results provide a molecular explanation for the multiple cellular responses to exogenous PLDs. These PLDs generate bioactive LPA from pre-existing Iysophosphatidylcholine in the outer membrane leaflet, resulting in activation of G-protein-coupled LPA receptors and consequent activation of Ras, Rho and Ca2+ signaling pathways. Unscheduled activation of LPA receptors may underlie, at least in part, the known pathogenic effects of exogenous PLDs.