In partnership with Sanofi, this combination regimen is currently being evaluated in two phase 2 studies, one in advanced ovarian cancer and one in neoadjuvant breast cancer.
Methodology & Results
- A total of 28 patients with certain platinum resistant gynecological cancers or HER2 non-overexpressing breast cancer received a combination of MM-121 and weekly paclitaxel until disease progression or intolerable toxicity was reported. Response was assessed every eight weeks.
- The observed safety profile of MM-121 in combination with weekly paclitaxel suggest a similar toxicity profile to that of weekly paclitaxel alone.
- Across all dosing cohorts, the overall clinical benefit rate was 70 percent. Forty-eight percent achieved a partial response (PR) and of those, 39 percent achieved a confirmed PR with a median duration of 2.7 months (range 1.7 – 15.1 months). Twenty-two percent experienced stable disease (SD) >4 months with a median duration of 5.3 months. Nine percent of patients had progressive disease (PD) at first assessment and 26 percent remain on study with a median on-study time of 13.5 months in 23 evaluable patients.
A Phase 1 Study of MM-111; a Bispecific HER2/HER3 Antibody Fusion Protein, Combined with Multiple Treatment Regimens in Patients with Advanced HER2 Positive Solid Tumors (Abstract #: 496P)
The Phase 1, multi-arm study examined the safety, pharmacokinetics and anti-tumor activity of MM-111, a bispecific antibody targeting the HER2/HER3 complex, combined with the standard of care HER2-targeting regimens of capecitabine, cisplatin and trastuzumab ; lapatinib +/- trastuzumab; and paclitaxel with trastuzumab. The study included patients with breast, gastric, esophageal and bladder cancers."This study shows that HER3 may indeed play an important role in the growth and resistance of multiple HER2+ solid tumor types," said Donald A. Richards, M.D., Ph.D., medical oncologist with Texas Oncology–Tyler, an affiliate of The US Oncology Network. "This study suggests that MM-111 can be safely combined with several trastuzumab-containing regimens." Phase 2 studies will further examine the role of MM-111 in the treatment of a variety of tumors, the first of which is expected to be initiated late this year.