Blood Journal
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Gemtuzumab ozogamicin (Mylotarg) as a single agent for molecularly relapsed acute promyelocytic leukemia

  1. Francesco Lo-Coco,
  2. Giuseppe Cimino,
  3. Massimo Breccia,
  4. Nélida I. Noguera,
  5. Daniela Diverio,
  6. Erica Finolezzi,
  7. Enrico M. Pogliani,
  8. Eros Di Bona,
  9. Concetta Micalizzi,
  10. Mariagrazia Kropp,
  11. Adriano Venditti,
  12. Agostino Tafuri, and
  13. Franco Mandelli
  1. From the Dipartimento di Biopatologia e Diagnostica per Immagini, Università Tor Vergata, Rome, Italy; Dipartimento di Biotecnologie Cellulari ed Ematologia, Università “La Sapienza,” Rome, Italy; Dipartimento di Medicina, Divisione di Ematologia, Università di Milano, Ospedale S. Gerardo, Milan, Italy; Dipartimento di Terapia Cellulare ed Ematologia, Divisione di Ematologia, Ospedale San Bortolo, Vicenza, Italy; Dipartimento di Ematologia ed Oncologia Pediatrica, Ospedale G. Gaslini, Genoa, Italy; and Ospedale Regionale, Catanzaro, Italy.

Abstract

The anti-CD33 antibody calicheamicinconjugate gemtuzumab ozogamicin (GO) was used to treat 16 patients with acute promyelocytic leukemia (APL) who had relapsed at the molecular level. Of these patients, 8 were experiencing a first, 5 a second, 2 a third, and 1 a fourth relapse. GO was administered at 6 mg/m2 for 2 doses, and patients achieving a new molecular remission (MR) (ie, negativity of the reverse transcriptase–polymerase chain reaction [RT-PCR] test for PML/RARα) received a third dose. MR was obtained in 9 (91%) of 11 patients tested after 2 doses and in 13 (100%) of 13 patients tested after the third dose. Of the 3 remaining patients, 1 achieved MR after one GO administration and received no further therapy owing to hepatic toxicity, and 2 showed disease progression during treatment. Quantitative RT-PCR studies showed that responding patients experienced a dramatic decline (at least 2 logs) of the PML/RARα transcript after the first GO dose. Of 14 responders, 7 remained in sustained MR for a median of 15 months (range, 7-31 months) while 7 experienced relapse at 3 to 15 months. GO was administered again in 2 patients with relapse, and both obtained a new MR. These data indicate that GO is highly effective as a single treatment for patients with molecularly relapsed APL including those with very advanced disease.

  • Submitted April 26, 2004.
  • Accepted May 30, 2004.
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