Case Report, J Clin Exp Oncol Vol: 8 Issue: 1

Influence of Long-term Abemaciclib, A New CDK 4/6 Inhibitor: Decrease in Liver Metastasis in a Patient Suffering from Metastatic Breast Cancer

Zorn O^1*, Miller J² and Heirler F²

¹Emergency Medicine, Klinikum Landshut, 84034 Landshut, Germany

²Sana Klinik Pegnitz, 91257 Pegnitz, Germany

*Corresponding Author: Oliver Zorn
Head of the Department, Emergency Medicine, Klinikum Landshut, 84034 Landshut, Germany
Tel: +491729876144
E-mail: o_zorn@gmx.de

Received: May 20, 2019 Accepted: June 03, 2019 Published: June 17, 2019

Citation: Zorn O, Miller J, Heirler F (2019) Influence of Long-term Abemaciclib, a New CDK 4/6 Inhibitor: Decrease in Liver Metastasis in a Patient Suffering from Metastatic Breast Cancer. J Clin Exp Oncol 8:1. doi: 10.4172/2324-9110.1000238

Abstract

Keywords: CDK 4/6 inhibitor; Breast cancer; Continuous therapy; Metastasis reduction; Tumour reduction; Side effect

Introduction

In this paper we would like to report the therapy used to decrease hepatic metastasis in an 82 year old female patient who earlier underwent surgery and radiation therapy for metastatic breast cancer in 2013. The patient was again presented with hepatic metastasis in 2018; she refused chemotherapy but agreed for continuous oral therapy. Hence she was treated with Abemaciclib 50 mg 1 – 0 – 1.

Case Report

A 82-year-old female patient, 86 kg, 163 cm (BMI: 32.2), married, two children, non-smoker, living in a normal social milieu, diabetes mellitus II since 1998 (HbA1c 11/2018: 6.7%), renal insufficiency gr 3-4, only appendectomy as a previous operation, no hypertension, moderate combined valvular aortic stenosis, erosive osteochondritis and physical disability according to age.

In May 2013 the patient was R0-mastectomied, right-hand side, in a pT3+pTis pN1 mi (1/2sn), L0, V0, M0. R0. G2, estrogen-receptor and progesteron-receptor positive, Her-2 positive, invasive lobular, G2 breast cancer, initial Ki 67 was 5%. In addition, LIN and DCIS were detected.

In August 2013 the patient was treated by means of breastpreserving surgery, left-hand side, in a pT1c, pN0 (0/3sn), M0, R0, L0, V0, G2, estrogen-receptor and progesteron-receptor positive, Her-2 negative, Ki 67: 2%, invasive ductal (NST). In August, radiation of the breast was carried out on the left-hand side. The clinical diagnostics (thorical X-ray, sonography of the liver and scintigraphy of the skeleton) were negative. In May 2013, antihormonal therapy started with Letrozol 2.5 mg. The patient refused further therapy.

In November 2018, hepatic metastasis was observed. Sonographic punctation histology: metastasis of the further known mamma carcinoma (ER: +, PR: +, HER-2: -, Ki 67: 17%) (Figure 1).

The patient refused the chemotherapy offered but agreed to continuous oral therapy with Abemaciclib 50 mg 1 – 0 – 1.

After six months of oral therapy, 2 × 50 mg daily, her pain subjectively decreased continuously. No relevant side effects were observed. After six months, hepatic metastasis was controlled by computer tomograph (Figure 2).

The significant reduction in the previously described hepatic metastasis was a surprise finding.

Discussion

After the introduction of the first effective drug combinations from the mid-1940s onwards, there was an improvement in the systemic treatment of oncological patients. In order to improve comparability, the therapies were standardized, and therapy in cycles of 21 days became increasingly established as the norm. In this way, it was possible to better compare the effectivity of known and new medications.

By means of individual reductions in doses, it was possible to demonstrate that certain substances had fewer side effects when administered on a weekly basis than on a three-weekly basis (e.g. Paclitaxel). At the same time, the effect on the tumour was sometimes more lasting. At the beginning of the 2000s, Imatinib – a tyrosinekinase inhibitor – was the first sustainable therapy strategy involving medication to be taken on a daily basis.

A new group of cancer therapeutics are cyclin-dependent kinases (CDK) inhibitors. CDK-inhibitors control cellular proliferation [1,2]. Abemaciclib is a cyclin-dependent kinase 4 and 6 inhibitor [3-5]. It is very effective in patients with metastatic breast cancer in combination with fulvestrant and aromatase inhibitors [6-9].

We use Abemaciclib because it can be administered orally twice a day in self-medication.

We expected a moderate increase in the size of the hepatic metastasis of the breast cancer [10-12]. In a patient with metastatic breast cancer under cytotoxic therapy over such a long period of time, we also expected to see more severe side effects [13]. The regularly implemented laboratory examinations did not show changes requiring treatment (such as neutropenia anaemia and thrombopenia). The body’s own repair and regeneration and mechanisms seem to compensate well for the cytotoxic effect. We were positively surprised to see that the patient reported a decline in upper abdominal pain. We were also surprised at the result of the control CT.

This clinical effect seems to be significant. On the one hand, side effects are moderate. On the other hand, oral administration every 12 hours seems to result in continuous plasma levels above the lower limit of the therapeutic index. In the event of continuous administration over several months, this apparently resulted in a lasting effect on the tumour.

Conclusion

It seems to be the case that although the higher doses are more effective, the more severe side effects result in most patients discontinuing the medication prematurely. For this reason it is not possible to observe an effect such as that observed by us.

While the therapeutic index of classic chemotherapeutics is very narrow, therefore requiring stringent dosing according to body surface, the therapeutic index of Abemaciclib seems to be much broader. We believe that the functioning of CDK 4/6 inhibitors is responsible for this effect.

Knowing this typical CDK 4/6 effect of Abemaciclib, it is important in assessing the therapeutic effect. In the future therefore, such clinical effects might be recorded in order to modulate Abemaciclib therapy. Further investigations are required.

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