Results include partial responses in small cohort of patients with brain metastasis from breast cancer (BMBC) and recurrent glioblastoma (rGBM)

MORRIS PLAINS, NJ, USA I September 18, 2020 I Immunomedics, Inc. (NASDAQ: IMMU) (“Immunomedics” or the “Company”), a leading biopharmaceutical company in the area of antibody-drug conjugates, today announced that Trodelvy delivered 150-fold and 40-fold the 50% inhibitory concentration (IC50) of SN-38 for BMBC and rGBM, respectively, and produced partial responses in both cohorts of brain cancer patients.

“These early intracranial responses are very encouraging signs of sacituzumab govitecan’s activity in central nervous system (CNS) tumors as previously observed in preclinical models,”1 said Andrew J. Brenner, M.D. Ph.D., Clinical Investigator, Institute for Drug Development; Co-Leader, Experimental and Developmental Therapeutics Program; S & B Kolitz/CTRC-Zachry Endowed Chair in Neuro-Oncology Research, Mays Cancer Center at UT Health San Antonio, San Antonio, TX, who reported the results in a mini oral session on CNS tumors at the ESMO Virtual Congress 2020. “With a hydrolysable linker that allows SN-38 to be released at the tumor site and given that SN-38 freely crosses the blood brain barrier and is active in the nanomolar range for most cancer cells, including triple-negative breast cancer (TNBC) and GBM, sacituzumab govitecan has the prerequisite ability to deliver therapeutically relevant concentrations of SN-38 across an undisrupted vasculature. The early clinical results in patients with neoplastic involvement of the brain warrant further development of Trodelvy in these aggressive and lethal cancers.”

At the time of data cutoff, 19 patients (7 BMBC and 12 rGBM) were enrolled into the study. Key clinical data from evaluable patients are summarized below. No new safety signals were observed.

  BMBC rGBM
Tumor response*, N 7 7
Partial response, n 2 2
Ongoing progression-free survival, n (range) 4 (161-279 days) 6 (7-315 days)
Residual measurable disease, n 4 7
Tumor SN-38 concentrations, N 4 6
Mean total SN-38 (nM) (range) 455 (174-1,160) 270 (93-687)
Mean free SN-38 (nM) (range) 73 (15-198) 46 (20-90)
SN-38G# detected in 1 patient in each cohort (nM) 3.4 5.8
* Per RANO criteria, # SN-38 glucuronide, an inactive metabolite of SN-38

“Brain metastasis is a significant concern in patients with TNBC, and we are very encouraged by these early-stage study results,” stated Dr. Loretta M. Itri, Chief Medical Officer of Immunomedics. “Additionally, given that GBM is a disease with great unmet need, we are working in close collaboration with Dr. Brenner and others, including the Southwestern Oncology Group, to design programs that could potentially elucidate the role of Trodelvy in the management of BMBC and rGBM.”

Patients with BMBC or rGBM were enrolled into the single center study (NCT03995706) to receive a single intravenous dose of Trodelvy at 10 mg/kg one day before surgical resection. Tumor and corresponding serum were collected during surgery to measure their levels of SN-38 and its metabolites. Following recovery, patients resumed Trodelvy treatment at 10 mg/kg on days 1 and 8 of 21-day cycles and were assessed for responses by MRI every third cycle using response assessment in neuro-oncology (RANO) criteria.

About Brain Cancer

According to the National Cancer Institute (NCI), an estimated 23,890 American will be diagnosed with brain cancer in 2020 and about 18,020 people will die from the disease in the U.S. this year.2  Among the numerous brain tumor types, glioblastoma (GBM) is the most aggressive, with median progression-free survival (PFS) and median overall survival (OS) from diagnosis of 6.2-7.5 months and 14.6-16.7 months, respectively, having been reported in clinical trials.3-6 For patients with recurrent GBM, chemotherapy regimens are associated with overall response rates of 4-9%, 6‑month PFS of 10-19%, and median OS of 5-10 months.7–11

References

  1. Pandey R, Gruslova A, Chiou J, et al. Stable isotope dilution LC-HRMS assay to determine free SN-38, total SN-38, and SN-38G in a tumor xenograft model after intravenous administration of antibody−drug conjugate (sacituzumab govitecan). Anal Chem. 2020;92(1):1260-1267.
  2. https://seer.cancer.gov/statfacts/html/brain.html Accessed on September 17, 2020.
  3. Stupp R, Mason WP, van den Bent MJ, et al. European Organisation for Research and Treatment of Cancer Brain Tumor and Radiotherapy Groups; National Cancer Institute of Canada Clinical Trials Group. Radiotherapy plus concomitant and adjuvant temozolomide for glioblastoma. N Engl J Med. 2005;352(10):987-996.
  4. Gilbert MR, Dignam JJ, Armstrong TS, et al. A randomized trial of bevacizumab for newly diagnosed glioblastoma. N Engl J Med. 2014;370 (8):699-708.
  5. Gilbert MR, Wang M, Aldape KD, et al. Dose-dense temozolomide for newly diagnosed glioblastoma: a randomized phase III clinical trial. J Clin Oncol. 2013;31(32):4085-4091.
  6. Chinot OL, Wick W, Mason W, et al. Bevacizumab plus radiotherapy-temozolomide for newly diagnosed glioblastoma. N Engl J Med. 2014;370 (8):709-722.
  7. Wong ET, Hess KR, Gleason MJ, et al. Outcomes and prognostic factors in recurrent glioma patients enrolled onto phase II clinical trials. J. Clin. Oncol. 17, 2572–2578 (1999).
  8. van den Bent MJ, Brandes AA, Rampling R, et al. Randomized phase II trial of erlotinib versus temozolomide or carmustine in recurrent glioblastoma: EORTC brain tumor group study 26034. J. Clin. Oncol. 27, 1268–1274 (2009).
  9. Batchelor TT, Mulholland P, Neyns B, et al. Phase III randomized trial comparing the efficacy of cediranib as monotherapy, and in combination with lomustine, versus lomustine alone in patients with recurrent glioblastoma. J. Clin. Oncol. 31, 3212–3218 (2013).
  10. Wick W, Puduvalli VK, Chamberlain MC, et al. Phase III study of enzastaurin compared with lomustine in the treatment of recurrent intracranial glioblastoma. J. Clin. Oncol. 28, 1168–1174 (2010).
  11. Taal W, Oosterkamp HM, Walenkamp AME, et al. Single-agent bevacizumab or lomustine versus a combination of bevacizumab plus lomustine in patients with recurrent glioblastoma (BELOB trial): a randomised controlled phase 2 trial. Lancet Oncol. 15, 943–953 (2014).

About Immunomedics

Immunomedics is a leader in next-generation antibody-drug conjugate (ADC) technology, committed to help transform the lives of people with hard-to-treat cancers. Our proprietary ADC platform centers on using a novel linker that does not require an enzyme to release the payload to deliver an active drug inside the tumor cell and the tumor microenvironment, thereby producing a bystander effect. Trodelvy, our lead ADC, is the first ADC the FDA has approved for the treatment of people with metastatic triple-negative breast cancer and is also the first FDA-approved anti-Trop-2 ADC. For additional information on the Company, please visit its website at https://immunomedics.com/. The information on its website does not, however, form a part of this press release.

SOURCE: Immunomedics