Clinical Trial: HER2+ Breast Cancer ROCHE WO42633

This blog was written using content provided by Jessica Severt, RN, BSN, Clinical Research Nurse Coordinator, Thompson Cancer Survival Center

Around 14% of new breast cancer diagnoses are categorized as HER2-positive which is generally associated with more aggressive cancer1. HER2-positive means an overexpression (too much) of the HER2 protein is found in the breast tumor tissue. Visit to learn more about HER2 Status.

The discovery of new treatments continues to improve the prognosis for this cancer. One of the clinical trials open at Thompson, ROCHE WO42633, is a study designed to evaluate the helpfulness and safety of a new combination of therapies for certain patients with HER2-positive breast cancer. 

Thompson Cancer Survival Center values the importance of clinical research and clinical trials to advance cancer care and cure. ROCHE WO42633 is only one example of the many currently open. Having a robust clinical research department with many open clinical trials empowers Thompson’s physicians with options and tools to offer premier cancer care to our patients who can remain in their own community. Thompson is one of only 288 cancer programs around the world and the only cancer program in East Tennessee with this trial open for enrollment.

Visit Thompson’s Clinical Research website to learn more about the program and this study. Click here to visit the study site on

Available Treatments

The treatment of HER2-positive breast cancer has been transformed over time. Not long ago, a HER2-positive subtype diagnosis was a poor prognostic marker for the patient due to the lack of useful drugs to stop the aggressive tumor growth.  Throughout the past decade, the introduction of targeted treatments has equipped providers with better options and resulted in better outcomes for patients who receive this diagnosis.

Targeted therapies, such as Trastuzumab (Herceptin), Pertuzumab (Perjeta), and Trastuzumab Emtansine (Kadcyla), have increased patient survival in early and advanced HER2-positive breast cancer. Many times these targeted therapies are given with standard chemotherapy. Depending on the patient’s tumor staging, the drug therapies may be given only in the neoadjuvant setting (before lumpectomy or mastectomy). In other cases, these treatments are given before and after surgery (adjuvant treatment).

Are Better Outcomes Possible?

These newer drugs and the sequence in which they are given help patients to live longer with fewer side effects. Studies have demonstrated that giving drug treatment before surgery improves long-term patient survival outcomes. Over the last several decades, studies have also shown that neoadjuvant chemotherapy, which is chemotherapy given before any surgical removal of cancer, has resulted in less extensive breast and axillary lymph node surgery. When cancer reduces in size in response to the before-surgery treatments, it can be down-staged which indicates the need for less extensive surgery. Less extensive surgery decreases the risk for and extent of associated short and long-term side effects.

These positive results are the outcomes providers and patients are hoping for, but what happens when cancer does not respond to the neoadjuvant therapy, rather it stays the same size or gets smaller, but does not completely go away?

When Cancer Doesn’t Respond

Studies indicate that leftover cancer in the breast or lymph nodes after neoadjuvant treatment means there is likely a higher risk of the cancer coming back. Thompson Cancer Survival Center has the ROCHE WO42633 clinical trial available to our patients because this study seeks to answer an important question:

For patients who do not completely respond, who still have breast cancer present, to their pre-surgery targeted/chemotherapy, what other drug therapies can we use to improve their treatment outcomes?

Increase Disease-Free Survival

According to the objective of ROCHE WO42633, this study hopes to determine if giving Trastuzumab Emtansine (Kadcyla) with Atezolizumab (Tecentriq) after neoadjuvant treatment, lumpectomy or mastectomy will increase the disease-free survival.

Trastuzumab Emtansine (Kadcyla) is already FDA approved for this patient population. It has shown good results for patients with HER2-positive breast cancer that have residual tumor at the time of surgery. But this study, ROCHE WO42633, is taking the treatment a step further and adding another drug, an immunotherapy (Atezolizumab) that is FDA approved for other cancer types. The goal is to see if these drugs can work together to get an even better outcome for patients.

Research Improves Patient Care

Clinical research is a valuable method to find better treatment options and methods for patients. All drugs start in clinical research studies. The advancement of cancer treatment and patient care is not possible without the valuable collaboration between scientists, researchers, clinical physicians, and patients. This study is a  Phase III, Randomized, Double-Blind, Placebo-Controlled Clinical Trial that should result in the highest levels of evidence-based recommendations for future treatments.



  1. National Cancer Institute. (n.d.) Cancer Stat Facts: Female Breast Cancer Subtypes. National Institute of Health, National Cancer Institute, SEER Program. Retrieved May 10, 2022.
  2. A Value-Based Approach to Treatment of HER2-Positive Breast Cancer: Examining the Evidence
  3. Residual cancer burden after neoadjuvant chemotherapy and long-term survival outcomes in breast cancer: a multicenter pooled analysis of 5161 patients.
  4. FDA approves ado-Trastuzumab emtansine for early breast cancer.,taxane%20and%20trastuzumab%2Dbased%20treatment.


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