Inclusion Criteria:
1. Males and females ages 18-65 years, inclusive
2. History of well-controlled mild or moderate persistent asthma for at least 6 months prior to screening.
3. Well controlled asthma demonstrated by asthma control test (ACT) score ≥20 at Visit 1.
4. Reactivity to AMP, as determined in Protocol 19512 (Screening Protocol of Asthmatic, Allergic Rhinitic, or Control Participants for Experimental Challenges). Reactivity is defined as having a PC20 AMP at or before 80mg/mL.
5. Two replicable (within 2 dose doublings) AMP challenges. The two AMP challenges must occur within 28 days of each other.
6. Pre-bronchodilator FEV1 ≥ 60% of predicted at screening.
7. Normal or not clinically significant (NCS) safety laboratory results from Visit 1 prior to Visit 2.
8. Negative pregnancy test for females who have not had a hysterectomy with oophorectomy or who have not been amenorrheic for 12 months or more.
9. Willing to abstain from caffeine for 24 hours prior to each AMP challenge.
10. Willing and able to give informed consent.
Exclusion Criteria:
1. Any chronic medical condition considered by the PI as a contraindication to participation in the study including significant cardiovascular disease, uncontrolled diabetes, chronic renal disease, uncontrolled chronic thyroid disease, history of chronic infections or immunodeficiency.
2. Inability to refrain from using inhaled corticosteroids (ICS), cromolyn, long-acting-beta-agonists (LABA), and leukotriene modifiers (LT) for 48 hours.
3. Pregnancy or nursing a baby.
4. A positive history for HIV, TB, HBV, or HCV.
5. Any asthma exacerbation requiring oral corticosteroids within 12 months of screening or that resulted in overnight hospitalization or an urgent care visit requiring additional treatment for asthma.
6. Uncontrolled asthma at enrollment Visit 1 defined as ACT score \<20.
7. Current smokers or a smoking history of ≥ 10 pack years. A subject may not have used any inhaled tobacco products in the 12-month period preceding Visit 1.
8. Known allergy/sensitivity to theophylline.
9. Any acute infection requiring antibiotics within 4 weeks or fever of unknown origin within 4 weeks of screening. Subjects having an intercurrent respiratory infection during the study will be permitted to reenroll.
10. Mental illness or history of drug or alcohol abuse that, in the opinion of the investigator, would interfere with the participant's ability to comply with study requirements.
11. Unwillingness to use reliable contraception if sexually active (IUD, birth control pills/patch).
