Optimal balance of benefit versus risk for tafenoquine in the treatment of Plasmodium vivax malaria.

A single 300 mg dose of tafenoquine (an 8-aminoquinoline), in combination with a standard 3-day course of chloroquine, is approved in several countries for the radical cure (prevention of relapse) of Plasmodium vivax malaria in patients aged ≥ 16 years. Despite this, questions have arisen on the optimal dose of tafenoquine. Before the availability of tafenoquine, a 3-day course of chloroquine in combination with the 8-aminoquinoline primaquine was the only effective radical cure for vivax malaria. The World Health Organization (WHO)-recommended standard regimen is 14 days of primaquine 0.25 mg/kg/day or 7 days of primaquine 0.5 mg/kg/day in most regions, or 14 days of primaquine 0.5 mg/kg/day in East Asia and Oceania, however the long treatment courses of 7 or 14 days may result in poor adherence and, therefore, low treatment efficacy. A single dose of tafenoquine 300 mg in combination with a 3-day course of chloroquine is an important advancement for the radical cure of vivax malaria in patients without glucose-6-phosphate dehydrogenase (G6PD) deficiency, as the use of a single-dose treatment will improve adherence. Selection of a single 300 mg dose of tafenoquine for the radical cure of P. vivax malaria was based on collective efficacy and safety data from 33 studies involving more than 4000 trial participants who received tafenoquine, including over 800 subjects who received the 300 mg single dose. The safety profile of single-dose tafenoquine 300 mg is similar to that of standard-dosage primaquine 0.25 mg/kg/day for 14 days. Both primaquine and tafenoquine can cause acute haemolytic anaemia in individuals with G6PD deficiency; severe haemolysis can lead to anaemia, kidney damage, and, in some cases, death. Therefore, relapse prevention using an 8-aminoquinoline must be balanced with the need to avoid clinical haemolysis associated with G6PD deficiency. To minimize this risk, the WHO recommends G6PD testing for all individuals before the administration of curative doses of 8-aminoquinolines. In this article, the authors review key efficacy and safety data from the pivotal trials of tafenoquine and argue that the currently approved dose represents a favourable benefit-risk profile.

Comment on 'The clinical pharmacology of tafenoquine in the radical cure of Plasmodium vivax malaria: An individual patient data meta-analysis'.

A single 300 mg dose of tafenoquine, in combination with chloroquine, is currently approved in several countries for the radical cure (prevention of relapse) of Plasmodium vivax malaria in patients aged ≥16 years. Recently, however, Watson et al. suggested that the approved dose of tafenoquine is insufficient for radical cure, and that a higher 450 mg dose could reduce P. vivax recurrences substantially (Watson et al., 2022). In this response, we challenge Watson et al.'s assertion based on empirical evidence from dose-ranging and pivotal studies (published) as well as real-world evidence from post-approval studies (ongoing, therefore currently unpublished). We assert that, collectively, these data confirm that the benefit-risk profile of a single 300 mg dose of tafenoquine, co-administered with chloroquine, for the radical cure of P. vivax malaria in patients who are not G6PD-deficient, continues to be favourable where chloroquine is indicated for P. vivax malaria. If real-world evidence of sub-optimal efficacy in certain regions is observed or dose-optimisation with other blood-stage therapies is required, then well-designed clinical studies assessing safety and efficacy will be required before higher doses are approved for clinical use.

Lornoxicam efficacy in acute pain (LEAP) trial.

Parenteral non-steroidal anti-inflammatory drugs (NSAIDs) are useful agents in the treatment of postoperative pain and other acute traumatic painful conditions such as fractures. Clinical trials with lornoxicam, an oxicam derivative, document its efficacy as a potent analgesic with excellent anti-inflammatory properties in painful and or/inflammatory conditions including postoperative pain and arthritic conditions. However, there is no documentation of the efficacy and tolerability of intravenous lornoxicam in Indian patients with acute painful conditions such painful traumatic conditions requiring hospitalisation and parenteral analgesics. The present study was undertaken to evaluate the efficacy and tolerability of intravenous lornoxicam in Indian patients with postoperative pain or other acute painful traumatic conditions requiring hospitalisation and parenteral analgesia in in-office practice conditions. In this multicentric, prospective, open, non-comparative phase IV, postmarketing surveillance study patients admitted in the nursing home for either postoperative pain or painful conditions requiring hospitalisation and parenteral analgesia were enrolled in the study after obtaining their informed consent. Of the 161 patients fulfilling the selection criteria, 148 met the selection criteria and were included in the efficacy analysis. Patients were treated with intravenous lornoxicam 8 mg twice or three times daily as required for up to 3 days. Efficacy variables included changes in severity of pain scores compared to baseline values, onset of pain relief and overall global efficacy. Tolerability was assessed through monitoring of treatment-emergent adverse events, physical examination, assessments of vital signs, and overall global assessment of tolerability. Results indicated that within 1 hour of administration of intravenous lornoxicam, the mean scores of pain severity were reduced by 39.46% and by 6 hours, there was a further 52% reduction in the mean scores. Therapy with intravenous lornoxicam was associated with a faster onset of action with 15.4% patients reporting pain relief within 10 minutes and 55.9% patients within 10 to 30 minutes. Overall, global assessment of efficacy was rated as good to excellent in 95.3% of the patients. Therapy with intravenous lornoxicam was well tolerated with only 5 patients reporting adverse events such as headache (n=3) and gastritis (n=1) of mild to moderate intensity but transient. Overall, global tolerability was rated as good to excellent in 98.4% of the total cases and fair in only 1.6% of the cases. In conclusion, the results of the present study indicate that intravenous lornoxicam is a potent NSAID with an optimal efficacy/toxicity ratio and thus could be a suitable therapeutic option in the management of patients with painful traumatic conditions requiring parenteral NSAIDs and hospitalisation.