herceptin, lapatinib remain effective afterwards if TDM-1 no longer effective

[Lani]

Good to know!

Ann Oncol. 2011 Apr 29. [Epub ahead of print]
Responses to subsequent anti-HER2 therapy after treatment with trastuzumab-DM1 in women with HER2-positive metastatic breast cancer.
Olson EM, Lin NU, Dipiro PJ, Najita JS, Krop IE, Winer EP, Burstein HJ.
Source
Department of Medical Oncology.
Abstract
BACKGROUND:
Women with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) can respond to multiple lines of anti-HER2 therapy. It is unknown whether these patients will derive further clinical benefit following treatment with trastuzumab-MCC-DM1 (T-DM1).

PATIENTS AND METHODS:
We retrospectively identified HER2-positive MBC patients treated with T-DM1 and characterized outcomes during subsequent lines of anti-HER2 therapy. Response was determined by a blinded radiology review. Time-dependent analyses were carried out using Kaplan-Meier estimates.

RESULTS:
We identified 23 patients treated with single-agent T-DM1 and report on the 20 patients who discontinued protocol therapy. All patients received trastuzumab-based metastatic therapy before initiation of T-DM1 [median 7 regimens (range 3-14)]. Of these 20 patients, 75% (15 of 20) received further therapy with or without anti-HER2 agents after discontinuing T-DM1. Partial response to either first- or second-subsequent line(s) of therapy was seen in 5 of 15 (33%) treated patients, including 33% (4 of 12) who received a regimen containing trastuzumab and/or lapatinib. Median durations of therapy to first- and second-subsequent regimens after T-DM1 were 5.5 and 6.4 months, respectively.

CONCLUSIONS:
In heavily pretreated HER2-positive MBC patients, prior exposure to T-DM1 does not exhaust the potential benefit of ongoing anti-HER2 therapy with trastuzumab- and/or lapatinib-based regimens.

PMID: 21531783 [P

[michka]

Thanks Lani. Very interesting. As usual!
It would also be interesting to know how long the 23 took TDM1 and why the treatment was discontinued for 20. I figure progression? 20/23? I hope I got it wrong.
"Median durations of therapy to first- and second-subsequent regimens after T-DM1 were 5.5 and 6.4 months, respectively". Every progress is good to take I first hope that TDM1 will be a breakthrough for many.

[Kim in DC]

Lani,

This post came right on time!
Kim

[StephN]

Probably another case of a SUBGROUP that has sensitivity to the targeted drugs having a better outcome.

[ElaineM]

Yes. Good to know !!!!!!!!