Polymerkonjugat bestående hovedsakelig av: fra 90 til 99,9 mol% av enheter med formel: -CH2 CH3-C-CO-NH-CHj-CHOH-CH3 fra 0,1 til 5 mol% av enheter representert med formel hvor en av Ra eller R2 er en kopolymer rest med formel T1 CH3-C-CO-NH-CH2-CO-A- og den andre er et hydrogenatom; fra O til 9,9 mol% av enheter representert ved formel r- CH3-C-CO-NH-CH2-CO-A-NH-CH2-CHOH-CH3 hvor R er en fenyl- eller t-butoksygruppe, R3 er H eller en acetylgruppe, A og Aj, som kan være like eller forskjellige, representerer en kjemisk enkeltbinding, en aminosyrerest eller en peptid-avstandsholder valgt fra pAla, Gly, Phe-Gly, Phe-Phe, Leu-Gly, Val-Ala, Phe- Ala, Leu-Phe, Leu-Ala, Phe-Leu-Gly, Phe-Phe-Leu, Leu- Leu-Gly, Phe-Tyr-Ala, Phe-Gly-Phe, Pge-Phe-Gly, Phe- Leu-TGly-Phe, Gly-Phe-Leu-Gly-Phe, Gly-pAla, Phe-Gly- pAla, Phe-Phe-pAla, Leu-Gly-pAla, Val-Ala-pAla, Phe- Ala-pAla, Leu-Phe-pAla, Leu-Gly-pAla, Phe-Leu-Gly-PAla, Phe-Phe-Leu-pAla, Leu-Leu-Gly-pAla, Phe-Tyr-Ala-pAla, Phe-Gly-Phe-p,. Phe-Phe-Gly-pAla, Phe-Leu-Gly-Phe-pAla eller Gly-Phe-Leu-Gly-Phe-pAla. Forbindelsene har antitumoraktivitet og forbedret vannoppløselighet og redusert toksisitet sammenlignet med paclitaxel eller dets kjente analoger. En fremgangsmåte for deres frem- stilling og farmasøytiske sammensetninger inneholdende dem er også beskrevet.Polymer conjugate consisting mainly of: from 90 to 99.9 mol% of units of formula: -CH 2 CH 3 -C-CO-NH-CH 2 -CHOH-CH 3 from 0.1 to 5 mol% of units represented by formula wherein one of Ra or R2 is a copolymer residue of formula T1 CH3-C-CO-NH-CH2-CO-A- and the other is a hydrogen atom; from 0 to 9.9 mol% of units represented by formula r-CH3-C-CO-NH-CH2-CO-A-NH-CH2-CHOH-CH3 where R is a phenyl or t-butoxy group, R3 is H or an acetyl group, A and Aj, which may be the same or different, represent a single chemical bond, an amino acid residue or a peptide spacer selected from pAla, Gly, Phe-Gly, Phe-Phe, Leu-Gly, Val-Ala, Phe - Ala, Leu-Phe, Leu-Ala, Phe-Leu-Gly, Phe-Phe-Leu, Leu-Leu-Gly, Phe-Tyr-Ala, Phe-Gly-Phe, Pge-Phe-Gly, Phe-Leu -TGly-Phe, Gly-Phe-Leu-Gly-Phe, Gly-pAla, Phe-Gly-pAla, Phe-Phe-pAla, Leu-Gly-pAla, Val-Ala-pAla, Phe-Ala-pAla, Leu -Phe-pAla, Leu-Gly-pAla, Phe-Leu-Gly-PAla, Phe-Phe-Leu-pAla, Leu-Leu-Gly-pAla, Phe-Tyr-Ala-pAla, Phe-Gly-Phe-p ,. Phe-Phe-Gly-pAla, Phe-Leu-Gly-Phe-pAla or Gly-Phe-Leu-Gly-Phe-pAla. The compounds have antitumor activity and improved water solubility and reduced toxicity compared to paclitaxel or its known analogues. A process for their preparation and pharmaceutical compositions containing them is also described.