1. Maximum tolerated dose (MTD (Time Frame - End of study (up to 14 months)): Assessment of the maximum tolerated dose based on the adapted 3+3 method
Secondary outcome:
1. Adverse Events (AEs) (Time Frame - End of study (up to 14 months)): Number of treatment-emergent AEs according to CTCAE 5.0
2. Serious Adverse Events (SAEs) (Time Frame - End of study (up to 14 months)): Number of treatment-emergent SAEs according to CTCAE 5.0
3. Laboratory abnormalities (Time Frame - End of study (up to 14 months)): Number of laboratory abnormalities
4. Electrocardiogram (ECG) abnormalities (Time Frame - End of study (up to 14 months)): Number of participants with ECG abnormalities
5. Echocardiogram (ECHO) abnormalities (Time Frame - End of study (up to 14 months)): Number of participants with ECHO abnormalities
6. Renal toxicities (Time Frame - End of study (up to 14 months)): Number of participants with renal toxicities
7. Area under the plasma concentration versus time curve (AUC) without RHT (Time Frame - day 2-3 (+/-3) in the study for each participant): AUC of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
8. Peak Plasma Concentration (cmax) without RHT (Time Frame - day 2-3 (+/-3) in the study for each participant): cmax of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
9. Time of Peak Plasma Concentration (tmax) without RHT (Time Frame - day 2-3 (+/-3) in the study for each participant): tmax of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
10. Clearance (Cl) without RHT (Time Frame - day 2-3 (+/-3) in the study for each participant): Cl of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
11. Mean Residence Time (MRT) without RHT (Time Frame - day 2-3 (+/-3) in the study for each participant): MRT of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
12. Percent Injected Dose (%ID) without RHT (Time Frame - day 2-3 (+/-3) in the study for each participant): %ID of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
13. Area under the plasma concentration versus time curve (AUC) with RHT (Time Frame - day 23-24 (+/-3) in the study for each participant): AUC of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
14. Peak Plasma Concentration (cmax) with RHT (Time Frame - day 23-24 (+/-3) in the study for each participant): cmax of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
15. Time of Peak Plasma Concentration (tmax) with RHT (Time Frame - day 23-24 (+/-3) in the study for each participant): tmax of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
16. Clearance (Cl) with RHT (Time Frame - day 23-24 (+/-3) in the study for each participant): Cl of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
17. Mean Residence Time (MRT) with RHT (Time Frame - day 23-24 (+/-3) in the study for each participant): MRT of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)
18. Percent Injected Dose (%ID) with RHT (Time Frame - day 23-24 (+/-3) in the study for each participant): %ID of DPPG2, non-liposomal DOX, liposomal encapsulated DOX and total DOX without RHT (cycle 1; 12 time points)