PUL-042 Treatment in Patients With Parainfluenza Virus (PIV), Human Metapneumovirus (hMPV) or Respiratory Syncytial Virus (RSV)

Inclusion Criteria:

• Subjects will be eligible for entry into the study if a nasopharyngeal swab ispositive for PIV, RSV, or hMPV (as a single pathogen or a mixed infection withrhinovirus) by molecular assay by a local laboratory AND subjects must fulfill thefollowing inclusion criteria to be eligible for participation in the study:

1. Subjects with hematologic malignancies (i.e., leukemia, lymphoma, or multiplemyeloma) or recipients of an allogeneic or autologous hematopoietic stem celltransplantation for one of the following diagnoses: leukemia, lymphoma,Hodgkin's lymphoma, non-Hodgkin's lymphoma, multiple myeloma, andmyelodysplastic and myeloproliferative disorder.

2. Subjects who have undergone active cytotoxic chemotherapy within 6 months orsubjects who are on an immunosuppressive therapy (e.g., alemtuzumab, ibrutinib,mycophenolate mofetil, corticosteroids ≥1mg/kg prednisone equivalent).

3. Subjects who are recipients of an allogeneic hematopoietic stem cell transplant (HSCT) must be deemed high risk with an Immunodeficiency Scoring Index (ISI) ,of greater or equal to 4.

4. Subjects who are recipients of an autologous HSCT must be within 3 months ofthe transplant procedure.

5. Subjects must be symptomatic with upper or lower respiratory tract symptomssuch as rhinorrhea, sore throat or cough and must be dosed within 6 days fromthe onset of symptoms.

6. Chest X-ray with a Radiologic Severity Index (RSI) score of 6 or lower.

7. Subjects must have pulse oximetry of hemoglobin saturation ≥ 93% on room air.

8. Spirometry (forced expiratory volume in one second [FEV1] and forced vitalcapacity [FVC]) ≥70% of predicted value.

9. Adult (≥ 18 years of age).

10. If female, must be either post-menopausal (one year or greater without menses),surgically sterile, or, for female subjects of child-bearing potential who arecapable of conception must be: practicing two effective methods of birthcontrol (acceptable methods include intrauterine device, spermicide, barrier,male partner surgical sterilization, and hormonal contraception) during thestudy and through 30 days after completion of the study. Abstinence is notclassified as an effective method of birth control.

11. If female, must not be pregnant, plan to become pregnant, or nurse a childduring the study and through 30 days after completion of the study. A pregnancytest must be negative at the Screening Visit, prior to dosing on Day 1.

12. If male, must be surgically sterile or willing to practice two effectivemethods of birth control (acceptable methods include barrier, spermicide, orfemale partner surgical sterilization) during the study and through 30 daysafter completion of the study. Abstinence is not classified as an effectivemethod of birth control.

13. Ability to understand and give informed consent.

Exclusion Criteria:

• Subjects will be excluded if they fulfill any of the following exclusion criteria:

1. Patients with a pulse oximetry of hemoglobin saturation less than 93% on roomair.

2. Known history of chronic pulmonary disease (e.g., asthma [including atopicasthma, exercise-induced asthma, or asthma triggered by respiratory infection],chronic pulmonary disease, pulmonary fibrosis, COPD), pulmonary hypertension,or heart failure.

3. Subjects treated for fungal, viral, or bacterial pneumonia in the previous 30days.

4. Exposure to any investigational agent (defined as any non-FDA-approved agent)within 30 days, or 5 half-lives of the investigational agent, whichever islonger, prior to the Screening Visit.

5. Allogeneic HSCT recipients with an ISI of 3 or less.

6. Autologous HSCT recipients more than 3 months after the transplant procedure.

7. Patients with a relapsed and/or refractory underlying hematologic malignancywith a life expectancy of less than 2 months.

8. HSCT recipients in the pre-engraftment period.

9. Chest X-ray with an RSI of >6.

10. Patients documented to be positive for other respiratory viruses (limited toinfluenza, SARS-CoV-2, adenovirus, or coronavirus) within 7 days prior to theScreening Visit, as determined by local testing (additional screening testingis not required).

11. Clinically significant bacteremia or fungemia within 7 days prior to theScreening Visit that has not been adequately treated, as determined by thePrincipal Investigator.

12. Any condition which, in the opinion of the Principal Investigator, wouldprevent full participation in this trial or would interfere with the evaluationof the trial endpoints.

13. Previous exposure to PUL-042 Inhalation Solution.