A 28-year-old non-smoking woman presents with episodic wheeze, chest tightness and cough, worse at night and with exercise. Spirometry shows FEV1/FVC ratio 0.68 with a 15 percent and 250 mL increase in FEV1 after bronchodilator. She uses a short-acting beta agonist inhaler about twice a week. According to Australian asthma guidelines, what is the most appropriate regular therapy?