The newest drug approved for pulmonary fibrosis is Jascayd (nerandomilast), which the FDA approved in October 2025 for idiopathic pulmonary fibrosis (IPF). It is the first new therapy approved for IPF in more than a decade, joining the two existing options, pirfenidone and nintedanib, that have been available since 2014.
How Jascayd Works
Jascayd belongs to a different class than existing treatments. It selectively blocks an enzyme called PDE4B, which plays a role in inflammation and the scarring process that stiffens lung tissue. By targeting this enzyme, the drug slows the rate at which the lungs lose their ability to expand and take in air.
In two large randomized trials, patients taking Jascayd had significantly less decline in lung capacity compared to those on placebo. Lung capacity is measured by forced vital capacity (FVC), essentially how much air you can forcefully exhale after a full breath. Earlier phase 2 data, published in the New England Journal of Medicine, showed the drug preserved lung function impressively: patients not on any other antifibrotic therapy lost a median of just 5.7 mL of FVC over 12 weeks, compared to a loss of 81.7 mL in the placebo group. That’s a difference of roughly 88 mL, which is clinically meaningful for a disease where every bit of lung function matters.
Importantly, the benefit held up in patients already taking pirfenidone or nintedanib. Those on background therapy saw a 62 mL advantage over placebo, suggesting Jascayd can work on top of existing treatment rather than requiring patients to switch.
Dosing and Side Effects
Jascayd is an oral tablet taken twice daily, roughly 12 hours apart. The standard dose is 18 mg, though it can be reduced to 9 mg if side effects become bothersome (with one exception for patients also taking pirfenidone).
The most common side effects reported in trials include diarrhea, upper respiratory infections, depression, decreased appetite, weight loss, nausea, fatigue, headache, vomiting, back pain, and dizziness. Diarrhea is the standout concern and has been a recurring theme across IPF treatments. In trial data comparing Jascayd with existing drugs, diarrhea was the most frequent adverse event regardless of which background therapy patients were on.
How It Compares to Existing Treatments
Pirfenidone and nintedanib have been the only approved options for IPF since 2014. Both slow lung function decline but don’t stop or reverse it, and both come with significant gastrointestinal side effects. Nintedanib is particularly associated with diarrhea, while pirfenidone commonly causes nausea, rash, and sun sensitivity.
Jascayd’s arrival changes the treatment landscape in two ways. First, it offers a third option for patients who can’t tolerate the existing drugs. Second, its ability to provide additional benefit on top of pirfenidone or nintedanib opens the door to combination approaches. Until now, combining pirfenidone and nintedanib together has been the only combination strategy studied, and real-world data from a long-term European study found that pairing was difficult for many patients. Of 38 patients tracked over a decade, 84% experienced side effects, with weight loss affecting more than half and over a quarter eventually stopping the combination entirely. Adding Jascayd to one existing drug, rather than stacking both older drugs together, may prove more tolerable, though long-term data will clarify this.
Other Drugs in Development
Beyond Jascayd, several investigational therapies are advancing through trials. One of the most closely watched is BMS-986278, an oral drug that blocks a receptor called LPA1. Increased activity at this receptor drives the scarring process in the lungs. In a phase 2 trial, the higher dose reduced the rate of lung function decline by 62% in IPF patients and by 69 to 74% in patients with progressive pulmonary fibrosis (a broader category that includes fibrotic lung diseases beyond IPF). These are striking numbers, and the drug is now in phase 3 trials.
For patients who develop high blood pressure in the lungs as a complication of their fibrosis, an inhaled therapy called Tyvaso DPI (treprostinil) is already FDA-approved specifically for pulmonary hypertension associated with interstitial lung disease. It doesn’t treat the fibrosis itself but improves exercise ability in patients whose lung scarring has raised pressure in the blood vessels of the lungs.
Who Qualifies for Treatment
Getting diagnosed with IPF is the first step, and it typically requires a combination of imaging, breathing tests, and sometimes a lung biopsy. For the major clinical trials that led to drug approvals, patients generally needed an FVC of at least 50% of predicted normal and had to be between 40 and 80 years old. They also needed to show they didn’t have significant airway obstruction (which would suggest a different condition like COPD) and couldn’t be on immunosuppressive medications.
In practice, doctors may prescribe approved drugs outside these exact criteria, but the trial boundaries give a rough sense of who has the strongest evidence behind treatment. Current guidelines from the major respiratory societies conditionally recommend nintedanib for progressive pulmonary fibrosis and recognize both nintedanib and pirfenidone for IPF. Jascayd’s approval adds a third endorsed option for IPF specifically.
Progressive pulmonary fibrosis, as defined by current guidelines, requires at least two of three criteria within the past year: worsening symptoms, worsening imaging, or declining lung function. This definition matters because it determines whether patients with fibrotic lung diseases other than IPF can access treatments originally studied in IPF populations.
What These Drugs Can and Cannot Do
No currently approved drug reverses pulmonary fibrosis or restores lost lung function. Every treatment on the market, Jascayd included, slows the rate of decline. For many patients, slowing that decline by even a modest amount translates into months or years of preserved independence, fewer hospitalizations, and delayed need for supplemental oxygen or lung transplant evaluation.
The combination of pirfenidone and nintedanib, when tolerated, roughly halved the monthly rate of FVC loss in one retrospective study, from about 27 mL per month to 11 mL per month. Researchers have described this approach as a potential “bridge to transplant” for patients with rapidly progressing disease, though tolerability remains a real barrier. Jascayd’s compatibility with existing antifibrotics may reshape how doctors approach combination therapy going forward, giving them a new building block that targets a different biological pathway.