Occupational Dust Exposure May Not Hinder Effectiveness of Anti-fibrotic Therapies, Study Suggests

Exposure to dust in the workplace for 10 years or longer seems to have no detrimental effect on the response of patients with idiopathic pulmonary fibrosis (IPF) to anti-fibrotic treatment with Esbriet (pirfenidone) or Ofev (nintedanib), a study has found.

The study “Antifibrotic treatment response and prognostic predictors in patients with idiopathic pulmonary fibrosis and exposed to occupational dust” was published in the journal BMC Pulmonary Medicine.

Evidence suggests that work-related factors, such as exposure to wood or organic dust, increases the risk of developing pulmonary fibrosis. However, it is not known how exposure to dust in the workplace may affect anti-fibrotic treatment and disease prognosis.

To address this question, a team of Italian researchers analyzed the relationship between IPF patients’ clinical characteristics at diagnosis, and after 12 months of treatment, according to their occupational dust exposure.

The team recruited 115 IPF patients who were referred to the University Hospital of Modena, and to the University Hospital of Napoli, both in Italy.

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Participants were divided into two groups: those with IPF who had 10 or more years of dust exposure (exposed group), and IPF patients exposed to dust for fewer than 10 years (non-exposed group).

Overall, 62 IPF patients were classified as exposed. In this group, researchers found a higher proportion (46.8%) of patients exposed to asbestos (silicate dusts). Seventeen patients were exposed to asbestos in the workplace, while the remaining patients were exposed outside work, either in their house or neighborhood.

Regarding treatment, about half of the patients were treated with Esbriet (marketed by Genentech) — 46.8% in the exposed group, and 50.9% in the non-exposed group. Treatment with Ofev (marketed by Boehringer Ingelheim) was less frequent — 37.1% of patients in the exposed group, and 41.5% in non-exposed patients. Both Esbriet and Ofev are approved therapies for IPF treatment.

On average, patients in the exposed group had a 36.74 years of exposure, while patients on the non-exposed group were exposed to dust for 1.2 years. The team found no significant differences in age or onset of respiratory symptoms between the two groups.

Pulmonary function, assessed by forced vital capacity (FVC%) and diffusing capacity for carbon monoxide (DLCO%), was similar for the two groups at baseline and 12 months after anti-fibrotic therapy. FVC measures the amount of air that can be forcibly exhaled from the lungs after taking the deepest breath possible, and DLCO gauges the ability of the lungs to transfer oxygen from the air to blood.

Researchers determined patients’ prognosis using the Gender, Age, Physiology (GAP) graded score that predicts IPF mortality, and the Composite Physiologic Index, which correlates with IFP progression and extent of pulmonary fibrosis.

Using both parameters, researchers saw that the prognosis of IPF patients was similar in both groups.

Starting long-term oxygen therapy (LTOT), a sign of disease worsening, also was not influenced by dust exposure. During follow-up, 38 patients initiated LTOT, corresponding to 57.9% of the exposed patients, and 52% of non-exposed, a difference not statistically significant.

Overall, “occupational dust exposure lasting 10 years or more does not seem to influence the therapeutic effects of antifibrotics, and the prognostic predictors in patients with IPF,” researchers wrote.

Despite these findings, “we believe that it is worthy to explore each possible factor which may influence the natural history and the response to therapy of IPF, a disease associated to rapid progression, fast worsening quality of life and high mortality” the team concluded.