The aim of this multi-center, randomized, double-blind, placebo-controlled trial is to compare the efficacy and safety of Dorithricin® lozenge - a triple combination of 0.5 mg tyrothricin, 1.0 mg benzalkonium chloride, and 1.5 mg benzocaine - in repeat dosing for 3 days to matched placebo lozenges in the treatment of acute pharyngitis in adults.

In this randomized, double-blind, placebo-controlled trial, adult patients with non-streptococcal sore throat and signs of moderate-to-severe associated pain (pain intensity on the 11-point Sore Throat Pain Intensity Scale NRS ≥7 and ≥50 mm on the subjective 0-100 mm visual analogue) are assigned to Dorithricin® or matching placebo lozenge treatment. Efficacy was assessed at the investigating center for 2 hrs after first dosing, and 3 days later (visit 2). The primary efficacy end-point is the percentage of total responders assessed at visit 2, i.e. complete resolution of throat pain and difficulty in swallowing at approx. 72 hrs after first application of treatment, Safety and local tolerability are also assessed.

Inclusion Criteria:

• Male and female outpatients aged ≥18 years
• Signed informed consent form
• Clinically diagnosed acute pharyngitis (TPA ≥5)
• Recent onset of symptoms (≤24 hours)
• Pain intensity of ≥8 on an 11-point NRS
• Difficulty in swallowing (100-mm VAS ≥50 mm)

Exclusion Criteria:

• Patients with strong suspicion of streptococcus A infection (McIsaac score ≥3)
• Positive rapid streptococcus A test (rapid antigen detection test) to exclude the major bacterial pathogen responsible for sore throat
• Purulent tonsillitis
• The use of systemic/local antibiotics in the throat area within 7 days prior to screening and during the study
• The use of any systemic analgesics/local analgesics in the throat area (e.g. non-steroidal drugs, [acetylsalicylic acid >100 mg], paracetamol) within 36 hours prior to screening and during the study
• The use of local anaesthetics for treatment of sore throat within 2 days prior to screening and during the study
• The use of any systemic anti-inflammatory drug/local anti-inflammatory drug in the throat area (e.g. glucocorticoids) within 4 weeks prior to screening and during the study
• The use of any other 'sore throat medication' (e.g., lozenges, drops, sprays) or other 'cold medication' that could have interfered with the results of the study within 7 days prior to screening and during the study

study protocol, statistical analysis plan, informed consent form, clinical study report are shared with all 26 recruited centers of the DoriPha investigators

investigation: participant, care provider and investigator blinded assessment: participant, care provider and investigator blinded outcome analysis: statistician blinded