Complementary Treatment with Mistletoe Extracts During Chemotherapy: Safety, Neutropenia, Fever, and Quality of Life Assessed in a Randomized Study

The objectives of this study were to assess the clinical response (neutropenia, fever, and quality of life according to EORTC QLQ-C30) and impact on the median disease-free survival time of VAE treatments during chemotherapy in breast cancer patients (stage T_1–3N_0–2M₀).

The present publication has been designed to identify the common effects of two different VAEs given to patients in parallel with chemotherapy.

A prospective, randomized, open-label clinical trial with equal size randomization into three groups (1:1:1) was conducted. Two groups received a complementary VAE treatment during the six consecutive cycles of cyclophosphamide, adriamycin, and 5-fluorouracil (CAF). These two groups were named according to the VAE administered: HxA group if Helixor A was administered and IMS group if Iscador M Spez was administered (Fig. 1). The third group received six CAF cycles without any complementary therapy and is referred to as the control group. The allocation to one group was fixed for the duration of the whole trial.

This clinical trial was conducted in two phases: the first phase lasted 18 weeks, which is the average duration of the six CAF cycles. The second phase lasted maximally 5 years, which is the duration of the follow-up.

None of the patients received VAEs after the end of chemotherapy. The present evaluation integrates the HxA and IMS groups into one group called VAE group, resulting in a de facto 2:1 randomization.

Breast cancer patients in the stages T_1–3N_0–2 M₀; treated at the Institute of Oncology and Radiology (IORS), National Cancer Research Center of Serbia in Belgrade; and prescribed six consecutive cycles of CAF after surgery were assessed for eligibility.

Additional inclusion criteria were female gender, age ≥18 years, Karnofsky index ≥60, leukocytes ≥3000/mm³, thrombocytes ≥100‚000/mm³, serum creatinine ≤2 mg%, serum glutamic oxaloacetic transaminase, and serum glutamic pyruvic transaminase ≤2.5 × the upper institutional limits.

Exclusion criteria were pregnancy or lactation; metastases; planned radiation or hormone therapy during six consecutive cycles of CAF; use of immunostimulant or immunosuppressive agents (e.g., corticosteroids) except for nausea and emesis; current use of other investigational agents; clinically relevant physical or mental illness such as serious infections, hepatic, renal, or other organ dysfunction or major depression; alcohol abuse, alcoholism, and oral or parenteral drug abuse; and methadone treatment.

Enrollment for this first part of the study started on December 14, 2005, and ended on February 15, 2007. In this time, 123 breast cancer patients were prescribed CAF and assessed for eligibility. Twenty-eight patients did not pass the screening, leaving 95 patients for randomization (Fig. 1).

For participation in the long-term follow-up, inclusion criteria were completion of six cycles of CAF and agreement to participate in the observation. Two patients in the VAE group were excluded due to an unknown metastatic status (M = X) before the start of chemotherapy, while one patient in the control group and one in the VAE group withdrew their consent to participate in the study. As a result, 56 of 59 patients of the VAE group and 29 of 30 patients of the control group were included in the long-term observation (Fig. 1). The follow-up began in June 2006 and ended in May 2012.

CAF therapy was administered to all patients in six cycles with a 3-week interval between each cycle. The scheduled dosage was 500 mg of cyclophosphamide, 50 mg of adriamycin, and 500 mg of 5 FU/1 m² skin surface administered at 1 day. No other antineoplastic or immunomodulating therapies were applied during chemotherapy. All patients received antiemetic therapy with a single dose of ondansetron chloride 8 mg, dexamethasone 8 mg, and ranitidine 50 mg, respectively, administered before each CAF cycle.

Participation in the study was offered to all VAE manufacturers and therefore allowed a variety of VAEs to be included. Two manufacturers agreed to participate and decided to use mistletoes from two different host trees used in the treatment of breast cancer. Patients randomly allocated to complementary therapy with VAEs therefore received either Iscador^® M special (IMS) or Helixor A (HxA). IMS is a fermented aqueous extract of V. album [L.] from the apple tree; fresh plant material, ratio of plant to extract = 1:5, manufactured by Weleda AG, Schwäbisch Gmünd, Germany. IMS comes in 1-mL ampules for injection and each ampule contains the fermented extract of 0.01, 0.1, 1, 2, or 5 mg of fresh VAE, respectively, in isotonic saline solution. HxA is an aqueous extract of V. album [L.] from the fir tree; fresh plant material, ratio of plant to extract = 1:20, manufactured by Helixor Heilmittel GmbH, Rosenfeld, Germany. HxA comes in 1-mL ampules for injection, each ampule containing the aqueous extract of 1, 5, 10, 20, 30, or 50 mg of fresh mistletoe herb, respectively, in isotonic saline solution.

Both VAEs were administered by subcutaneous injections of 1 mL into the upper abdominal region three times per week (e.g., Monday, Wednesday, and Friday). The patients in the VAE groups were instructed to inject themselves subcutaneously. To investigate the safety of dosages indicated on the products' package leaflets, these same dosages were applied in this study. The dosage of VAE was increased stepwise: for IMS, 2 × 0.01, 2 × 0.1, 11 × 1, 8 × 2 mg, and remaining doses were 5 mg; for HxA, 3 × 1, 3 × 5, 3 × 10, 3 × 20, 3 × 30 mg, and the remaining doses were 50 mg. In case of local inflammatory skin reactions >5 cm or body temperature >38°C, VAE injections were reduced to the last well-tolerated dosage. An average of 53.8 ± 2.6 injections with altogether 174 mg of IMS per patient and an average of 52.3 ± 2.8 injections with altogether 2812 mg of HxA per patient were administered in the VAE group. VAE injections were stopped at the latest 3 weeks after the last CAF cycle to ensure that only direct interactions between VAEs and CAF could be the cause of different results in the 5-year follow-up.

The control group did not receive additional VAE treatment to chemotherapy.

Temperature was measured sublingually in the morning on days of VAE injections. The same thermometer type (Geratherm Medical AG) was handed out to the patients for this purpose. Temperature and the diameter of local inflammatory reactions at the injection site were recorded in a diary. Unexpected rises in temperature outside the fixed measurement points were recorded in a supplementary field of the diary. Fever was defined as a temperature >38°C.

Blood samples were collected before every new CAF cycle. Neutropenia was defined as a neutrophil count of <1000/μL blood. Neutropenia and a body temperature >38°C were defined as cases of neutropenic fever.

Quality of life was documented during CAF therapy with the EORTC QLQ-C30 in the official Serbian translation.¹³ The EORTC QLQ-C30 has 30 questions summarized in 15 scores: six scores for functions and nine for symptoms. Patients filled in the EORTC QLQ-C30 seven times: once at baseline and each time before the CAF was injected.

Relapse and/or metastasis were documented annually at the prescribed routine follow-up visits to the study center for 5 years. The results were documented in case report forms designed for this study. A deviation of ±2 months was tolerated for the annual visits. The follow-up for an individual patient ended with the occurrence of a relapse or a metastasis.

Adverse events were assessed by interviewing the patients and by analyzing laboratory results at each visit. Regarding local inflammatory reactions at the injection site, only those larger than 5 cm in diameter were considered as adverse events.

The chance to be allocated to any of the three groups (HxA group, IMS group, and control group) was 1:1:1. Variable block sizes were used for randomization without previous stratification. The randomization sequence was generated using SPSS^® (SPSS^® 14.0.1; SPSS, Inc., Chicago, IL). Allocation concealment was implemented by using sealed envelopes. Investigators at the outpatient clinic, IORS, enrolled patients, while the sealed randomization envelopes were stored in the Department of Study Coordination, IORS, and released consecutively for each enrolled patient.

The study was not placebo controlled as the typical and time-dependent reactions following subcutaneous VAE injections (local inflammatory reactions at the injection site, increased body temperature, and flu-like symptoms) cannot be imitated by a pseudoplacebo.

Statistical analysis was performed with SAS 9.4 and included all participating patients. The Mann–Whitney test, Fisher's exact test, Kruskal–Wallis test, and t-test were used to check the balance of demographic and clinical baseline characteristics and the balance of therapies after chemotherapy. The disease-free survival curves were plotted with the Kaplan–Meier method and compared using the log-rank test (Cox-Mantel).

The study was approved by the Ethics Committee of the National Cancer Research Center of Serbia without modifications (date: October 3, 2005) and by the Serbian Drug Agency (date: November 1, 2005). The study was conducted in compliance with the Declaration of Helsinki, Good Clinical Practice guidelines, and national laws. A registration of the study in the European Union (EU) has been rejected because Serbia is outside of the EU. All participants received patient insurance. All participants signed an informed consent before inclusion. Clinical Research Dr. Tröger (CRDT) was responsible for planning, conducting, monitoring, and analysis of the study. The two sponsors performed two audits at CRDT and one at the study site during the study. No violation of Good Clinical Practice guidelines was detected.

The VAE and control groups were well balanced and did not differ significantly in their demographic and clinical characteristics (Table 1).

No long-lasting fever occurred in any of the two patient groups. The highest recorded temperature in the control group was 39.7°C, and the highest recorded temperature in the VAE group was 38.6°C (Fig. 2). Both patients recovered a temperature of 36.6°C and 36.2°C, respectively, at the next measurement point. In total, fever was observed in two different patients for the time span of one measurement point in both groups. VAE injections, even if causing local inflammatory skin reactions >5 cm, did not lead to an increase of the mean recorded temperature (Table 2).

Fifty-nine of 64 VAE patients and 30 of 31 control patients could be analyzed for neutropenia. Neutropenia was detected 10 times in 10 different patients (17%) of the VAE group and nine times in eight different patients (27%) of the control group (Table 3). Fisher's exact test according to the sequentially rejective Holm procedure indicates a trend (p = 0.178) toward less neutropenia in the VAE group. Patient #51 in the control group suffered from neutropenic fever (38.7°C), while no neutropenic fever occurred in the VAE group.

During chemotherapy with CAF, 3 of 15 items measured with the EORTC QLQ-C30 differed in a statistically significant and clinically relevant (score difference >7) manner between the VAE group and the control group: role functioning, pain, and appetite loss (Fig. 3 and Table 4).

Apart from local inflammatory skin reactions at the injection site (maximal diameter observed: 12 cm), no adverse events relating to VAEs were detected.

Fifty-six of 64 VAE patients and 29 of 31 control patients could be analyzed. Fifteen of 56 patients in the VAE group and 8 of 29 patients in the control group developed relapse or metastasis within 5 years (Fig. 4). The difference between both groups is not statistically relevant (p = 0.7637, log-rank test). The median disease-free survival time could not be calculated because the highest probability of relapse or metastasis in 5 years was 28%.

All patients were separately analyzed according to their following adjuvant treatment, which consisted of hormone or radiotherapy. No differences could be detected in their relapse and metastasis rates (data not shown).