What is Pneumocystis jirovecii pneumonia (PJP)?

From the Guidelines

PJP, or Pneumocystis jirovecii pneumonia, is a serious fungal lung infection that primarily affects people with weakened immune systems, and prophylaxis with trimethoprim-sulfamethoxazole (TMP/SMX) is highly effective in preventing PJP, reducing its occurrence by 91% compared to placebo or no treatment 1. PJP is caused by the fungus Pneumocystis jirovecii and is particularly common in HIV/AIDS patients with CD4 counts below 200 cells/mm³, organ transplant recipients, and those on immunosuppressive medications.

Key Points

• Prevention typically involves prophylactic medication with TMP/SMX at a dose of one double-strength tablet daily or three times weekly.
• For those who cannot tolerate this medication, alternatives include dapsone, atovaquone, or pentamidine 1.
• Treatment for active PJP infection usually requires a 21-day course of high-dose TMP/SMX.
• Early symptoms include fever, dry cough, shortness of breath, and fatigue that progressively worsens.
• PJP is particularly dangerous because it can rapidly progress to respiratory failure if not treated promptly, making early diagnosis and treatment crucial for immunocompromised individuals.

Prophylaxis Recommendations

• Prophylaxis against PJP should be used in allogeneic HCT recipients, patients receiving CAR T-cell therapy, and patients with ALL throughout antileukemic therapy 1.
• Patients should receive prophylaxis against PJP for a minimum of 2 months after alemtuzumab and until the CD4 count is >200 cells/mcL.
• Other patients who should receive PJP prophylaxis include those receiving treatment with select phosphatidylinositol-3-kinase inhibitors, patients with neoplastic diseases receiving intensive corticosteroid treatment, and patients receiving temozolomide 1.

From the FDA Drug Label

Atovaquone oral suspension is indicated for the prevention of Pneumocystis jirovecii pneumonia (PCP) in adults and adolescents (aged 13 years and older) who cannot tolerate trimethoprim-sulfamethoxazole (TMP-SMX). Atovaquone oral suspension is indicated for the acute oral treatment of mild-to-moderate PCP in adults and adolescents (aged 13 years and older) who cannot tolerate TMP-SMX.

Pneumocystis jirovecii pneumonia (PJP), also referred to as PCP, is a condition that atovaquone oral suspension is indicated for the prevention and treatment of, in adults and adolescents who cannot tolerate trimethoprim-sulfamethoxazole (TMP-SMX) 2.

• It is not explicitly defined in the provided drug label, but it is implied to be a type of pneumonia caused by the Pneumocystis jirovecii organism.

From the Research

Definition and Causes of Pneumocystis jirovecii Pneumonia (PJP)

• Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that can cause severe pneumonia in immunocompromised hosts 3, 4.
• The risk factors for PJP include HIV, organ transplant, malignancy, certain inflammatory or rheumatologic conditions, and associated therapies and conditions that result in cell-mediated immune deficiency 3.
• PJP is caused by the yeast-like fungus P. jirovecii, which is a unique fungal pathogen that can affect various types of immunocompromised patients 4.

Clinical Manifestations and Diagnosis of PJP

• The clinical signs of PJP are nonspecific, and definitive diagnosis requires direct detection of the organism in lower respiratory secretions or tissue 3.
• Laboratory diagnosis is usually nonspecific, but serum 1,3-β-D-glucan (BDG) has a high diagnostic odds ratio, and combining BDG and lactic dehydrogenase can improve the diagnosis of PJP 4.
• Histopathological staining and polymerase chain reactions can detect the presence of P. jirovecii, but cannot discriminate between infection and colonization when the result is positive 4.

Treatment and Prevention of PJP

• The first-line therapy for prophylaxis and treatment of PJP is trimethoprim-sulfamethoxazole (TMP-SMX), but intolerance or allergy, and rarely treatment failure, may necessitate alternate therapeutics 3.
• Low-dose TMP-SMX has been shown to be effective and safe for the treatment of PJP, with a significant decrease in adverse reactions compared to conventional dosing 5, 6.
• Other treatment options include dapsone, pentamidine, atovaquone, clindamycin, primaquine, and caspofungin, which can be used as adjunctive therapy or in patients with G6PD deficiency 3, 7.
• Early diagnosis and treatment can improve the survival rate for PJP in immunocompromised patients, and enzyme activity detection is important for anti-PJP treatment in patients with G6PD deficiency 7.