A Pharmacokinetic Study of JK1211(Itraconazole [Itrizole]) Oral Solution in Participants With Deep Mycosis and Those With Febrile Neutropenia Suspected of Fungal Infection

The purpose of this study is to assess the pharmacokinetics (how the drug is absorbed in the body, distributed within the body, and how it is removed from the body over time) of itraconazole (ITCZ) oral solution in participants with Systemic Fungal Infection (SFI) and those with febrile (with fever) neutropenia (FN, decrease in white blood cells) suspected of fungal infection.

This is an open-label (all people know the identity of the intervention), multicenter (conducted in more than 1 center) and uncontrolled (no competitive drugs involved) study. Participants with SFI will receive treatment with ITCZ oral solution or switch treatment from intravenous (into a vein) infusion of itraconazole (ITCZ-intravenous) to ITCZ oral solution as per Investigator's discretion. All the participants with FN suspected of fungal infection will receive the switch treatment from ITCZ- intravenous to ITCZ oral solution. The study will include 3 periods: Pre-observation period (7 days), Treatment period (85 days for ITCZ oral solution monotherapy and 99 days for switch treatment) and Follow-up observation period (30 days). The participants who receive ITCZ oral solution monotherapy will receive ITCZ oral solution without ITCZ-intravenous in the dose range of 20 milliliter (ml) per day to 40 ml per day for 12 weeks (85 days) and those on the switch treatment will receive 400 milligram (mg) per day ITCZ-intravenous twice for first 2 days followed by 200 mg per day ITCZ-intravenous up to 14 days and then they will be administered treatment as per ITCZ oral solution monotherapy. Efficacy will primarily be evaluated by assessing the pharmacokinetics. Participants' safety will be monitored throughout the study.

Eligibility Criteria:
Inclusion Criteria:

* In case of participants with deep-seated mycosis (systemic fungal infection \[SFI\]) they should be either clinically suspected case or proven case
* All participants administered need to be hospitalized during the itraconazole intravenous treatment
* For participants with febrile (with fever) neutropenia (a decrease in white blood cells) suspected of fungal infection who have persistent fever (greater than equal to 37.5 degree celsius; greater than equal to 3 days) and have neutrophil count less than 500 per cubic millimeter (or less than 1000 per cubic millimeter and expected to decrease toward less than 500 per cubic millimeter

Exclusion Criteria:

* No past history of hypersensitivity to azole antifungal agents
* No current medication with antifungal agents such as amphotericin B (intravenous injection \[injection of a substance into a vein\], tablets, syrup), nystatin (tablets), fluconazole (capsules, intravenous injection), flucytosine (oral agent), miconazole (intravenous injection, gel), micafungin (intravenous infusion), fosfluconazole (intravenous injection,) voriconazole (intravenous injection, tablets), liposomal amphotericin B (intravenous injection), posaconazole
* No medication with itraconazole in any formulation within the last 28 days
* Participants with history of severe hepatic disease (except hepatic dysfunction because of fungal infection) and congestive heart failure
* Female participants who are either pregnant, nursing, suspected to be pregnant or will become pregnant during the trial duration