A therapeutic nanoparticle comprising: 5 to 30 weight percent of a therapeutic agent; 10 to 99 weight percent of a diblock poly(lactic) acid-poly(ethylene)glycol copolymer (PLA-PEG), wherein said poly(lactic) acid-poly(ethylene)glycol copolymer comprises poly(lactic acid) having a number average molecular weight of 15 to 20 kDa and poly(ethylene)glycol having a number average molecular weight of 4 to 6 kDa; 0 to 75 weight percent poly(lactic) acid or poly(lactic) acid-co-poly (glycolic) acid (PLGA); and wherein the hydrodynamic diameter of the therapeutic nanoparticle is 60 to 120 nm; with the proviso that the therapeutic nanoparticle is not a nanoparticle consisting of docetaxel, PLA having a MW of 30 kDa, a diblock PEG-PLA copolymer comprising PEG of MW 5000 and polylactide of MW 20,000 and optionally octadecyl-4(maleimidomethyl) cyclohexane-carboxylic amide (OMCCA), prepared from PLA, PEG-PLA and docetaxel at an initial weight ratio of 88:38:10 or PLA, PEG-PLA, docetaxel and OMCCA at an initial weight ratio of 88:38:10:20 by the method of Example 3 of European Patent Application Publication EP 2106806A1 in which 88 mg of the polymer PLA (polylactide, 30 KDa purchased from Boehringer Ingelheim) and 30mg of the co-polymer PEG-PLA 5:20 (polyethylene glycol of MW of 5000 and polylactide MW of 20,000) were dissolved in 20ml acetone, a water-miscible organic solvent; to this organic phase 10mg of the drug docetaxel were added; for coupling of an antibody, to the organic phase, 20mg of the linker OMCCA were added; the resulting organic phase was then added to 50ml of aqueous phase which contained 100mg Solutol ® HS 15 (BASF, Ludwigshafen, Germany), as a surfactant (Macrogol 15 hydroxystearate); the dispersion was mixed at 900 rpm over 1 hr and then evaporated under reduced pressure to 20ml, the NPs were washed with Phosphate Buffered Saline 5-6 times using vivaspin 300 KDa cut-off. 5 to 30 weight percent of a therapeutic agent; 10 to 99 weight percent of a diblock poly(lactic) acid-poly(ethylene)glycol copolymer (PLA-PEG), wherein said poly(lactic) acid-poly(ethylene)glycol copolymer comprises poly(lactic acid) having a number average molecular weight of 15 to 20 kDa and poly(ethylene)glycol having a number average molecular weight of 4 to 6 kDa; 0 to 75 weight percent poly(lactic) acid or poly(lactic) acid-co-poly (glycolic) acid (PLGA); and wherein the hydrodynamic diameter of the therapeutic nanoparticle is 60 to 120 nm; with the proviso that the therapeutic nanoparticle is not a nanoparticle consisting of docetaxel, PLA having a MW of 30 kDa, a diblock PEG-PLA copolymer comprising PEG of MW 5000 and polylactide of MW 20,000 and optionally octadecyl-4(maleimidomethyl) cyclohexane-carboxylic amide (OMCCA), prepared from PLA, PEG-PLA and docetaxel at an initial weight ratio of 88:38:10 or PLA, PEG-PLA, docetaxel and OMCCA at an initial weight ratio of 88:38:10:20 by the method of Example 3 of European Patent Application Publication EP 2106806A1 in which 88 mg of the polymer PLA (polylactide, 30 KDa purchased from Boehringer Ingelheim) and 30mg of the co-polymer PEG-PLA 5:20 (polyethylene glycol of MW of 5000 and polylactide MW of 20,000) were dissolved in 20ml acetone, a water-miscible organic solvent; to this organic phase 10mg of the drug docetaxel were added; for coupling of an antibody, to the organic phase, 20mg of the linker OMCCA were added; the resulting organic phase was then added to 50ml of aqueous phase which contained 100mg Solutol ® HS 15 (BASF, Ludwigshafen, Germany), as a surfactant (Macrogol 15 hydroxystearate); the dispersion was mixed at 900 rpm over 1 hr and then evaporated under reduced pressure to 20ml, the NPs were washed with Phosphate Buffered Saline 5-6 times using vivaspin 300 KDa cut-off.