WO1999056742A1

WO1999056742A1 - Chemotherapeutic treatment

Info

Publication number: WO1999056742A1
Application number: PCT/NZ1999/000055
Authority: WO
Inventors: Mark James Mckeage; Gabi Haddad
Original assignee: Auckland Uniservices Limited
Priority date: 1998-05-04
Filing date: 1999-05-04
Publication date: 1999-11-11
Also published as: AU3961899A

Abstract

This invention relates to chemotherapeutic treatments involving the use of chemotherapeutic agents which, as a side effect, cause peripheral neurotoxicity. In particular, the invention provides methods by which chemotherapeutic strategies can be followed using such chemotherapeutic compounds but with reduced peripheral neurotoxicity which methods involve pre-administration of paclitaxel or a paclitaxel equivalent at least 4 hours prior to administration of the chemotherapeutic compound.

Description

1 CHEMOTHERAPEUTIC TREATMENT

This invention relates to chemotherapeutic treatments involving the use of chemotherapeutic agents which, as a side effect, cause peripheral neurotoxicity. In particular, the invention provides methods by which chemotherapeutic strategies can be followed using such chemotherapeutic compounds but with reduced peripheral neurotoxicity.

BACKGROUND

Cisplatin and paclitaxel are cancer chemotherapeutic drugs commonly given in combination for the treatment of patients with ovarian or lung cancers. They are usually administered as separate intravenous infusions without any deliberate interval between their administration. However, while their use in combination has been shown to improve the survival of patients with ovarian cancer (McGuire et al (1996)), the delivery of paclitaxel and cisplatin is limited by neurotoxicity symptoms, e.g. numbness or pins and needles in the hands and feet, incoordination and deafness. Some combination regimens have also been associated with severe peripheral neurotoxicity (Connelly et al (1996), Gordon et al (1997)) which ultimately limits the amount of treatment that can be given. Treatments for reducing the neurotoxicity of paclitaxel and cisplatin are therefore being pursued including those based on neuroprotective L-type calcium channel blockers (Cassidy et al (1998)), ACTH analogues (Roberts et al ( 1997)) and nucleophilic sulphur thiols (Kemp et al (1996)).

This propensity to cause damage to peripheral nerves is not restricted to cisplatin and paclitaxel but is common to a number of other chemotherapeutic agents. These include the paclitaxel analogs or derivatives and cisplatin derivatives.

It is therefore an object of this invention to provide an approach to combination therapy using cisplatin and paclitaxel (and their equivalents) which will deliver the desirable anti-tumor effect of such chemotherapeutic drugs while minimising peripheral neurotoxicity, or at least to provide the public with a useful choice. 2 SUMMARY OF THE INVENTION

Accordingly, in a first aspect, the invention provides a method for reducing neurotoxicity symptoms (including peripheral neurotoxicity symptoms) in a patient suffering from cancer and undergoing therapy with a non-taxane neurotoxic chemotherapeutic drug while maintaining the anti-tumor effectiveness of said drug, which method comprises the step of administering to said patient an effective amount of paclitaxel or of a paclitaxel equivalent between 4 and 72 hours prior to administration of said neurotoxic chemotherapeutic drug.

As used herein, the term "non-taxane" means a other than paclitaxel or a paclitaxel equivalent.

An "effective amount" preferably means an amount of paclitaxel or of a paclitaxel equivalent sufficient to stabilise neuronal microtubules within the patient.

In a preferred embodiment, the neurotoxic chemotherapeutic drug is a platinum- based chemotherapeutic drug or is hexamethylmelamine.

Conveniently, the platinum-based chemotherapeutic drug is cisplatin or a cisplatin analog or derivative such as carboplatin, oxaliplatin, diaminocylohexane platinum complexes, BBR 3464 or AMD 473.

Most conveniently, the platinum-based chemotherapeutic drug is cisplatin or oxaliplatin.

As used herein, the term "paclitaxel equivalent" means an analog or derivative of paclitaxel, a chemotherapeutic drug having properties equivalent to paclitaxel, or compound having microtubule stabilising properties equivalent to paclitaxel. Such equivalents therefore include docetaxel (taxotere), cryptophycins, eleutherobins, lanliamlides, epothilones, benzoylphenylureas and solubilised conjugates of paclitaxel.

It is however presently preferred that the compound which is preadministered is paclitaxel itself, or docetaxel. Conveniently, the paclitaxel or paclitaxel equivalent is administered from 12 to 48 hours prior to administration of the neurotoxic chemotherapeutic drug, more conveniently from 20 to 28 hours prior to administration of the neurotoxic chemotherapeutic drug, and still more conveniently about 24 hours prior to administration of said neurotoxic chemotherapeutic drug.

In still a further aspect, the invention relates to the use of paclitaxel or a paclitaxel equivalent in the preparation of a medicament for reducing peripheral neurotoxicity symptoms associated with subsequent administration of a non-taxane neurotoxic chemotherapeutic drug to a patient undergoing cancer therapy.

In one preferred embodiment, the use is of paclitaxel.

In another preferred embodiment, the use is of docetaxel.

DESCRIPTION OF THE DRAWINGS

While the invention is broadly as defined above, it is not limited thereto and also- includes embodiments of which the following description provides examples. In particular, a better understanding of the present invention will be gained through reference to the accompanying drawings in which:

Figure 1; Sensory nerve conduction velocity (SNCV) in animals treated with cisplatin 24 hours before paclitaxel (A) or paclitaxel 24 hours before cisplatin (B) once a week intraperitoneally with doses of pacKtaxel and cisplatin respectively of 9 and 8.33 μmol/kg ( Q), 12 and 6.67 μmol/kg (Δ), 15 and 5 μmol/kg (V) or drug vehicle alone (• ). Symbols, mean ± standard error, n =7- 12.

Figure 2: Isobologram showing the effects of cisplatin and paclitaxel on SNCV given alone (filled symbols) or combined (open symbols). Isoboles for cisplatin given 24 hours before paclitaxel ( J) and the reverse sequence of treatment (O) are shown. The arrows indicate data points where altered SNCV had not been achieved. 4

Figure 3: Relationship between cisplatin dose and change in diameter of nucleoli of dorsal root ganglia neurons in animals given cisplatin alone (< >) or in combination

with paclitaxel ( J). There was a significant difference (P=0.004) in the regression slopes of the two lines.

Figure 4: Tumor growth delay in C57B1/6 mice bearing colon 38 tumors treated with; (A) paclitaxel (23.4 μmol/kg) alone ( ■), saline drug vehicle ( •) or Cremophor EL drug vehicle ( O), or (B); paclitaxel (23.4 μmol/kg) followed 24 hours later by cisplatin (23.3 μmol/kg) ( T), cisplatin (23.3 μmol/kg) alone (V), or saline drug vehicle ( •).

Figure 5: Relationship between cumulative dose of oxaliplatin and altered SNCV in animals given oxaliplatin (5 μmol/kg per week) alone (squares) or oxaliplatin (5 μmol/kg per week) 24 hours after docetaxel (2.5 μmol/kg per week) (triangles). The symbols and error bars represent the mean and standard deviation of changes in SNCV measured in two independent experiments.

DESCRIPTION OF THE INVENTION

As described above, the present invention represents a new approach to combination therapy in treating cancer. This approach allows neurotoxic chemotherapeutic compounds or drugs to be used with reduced peripheral neurotoxicity to a patient but without compromising the anti-tumor effectiveness of the chemotherapeutic drug(s).

The principal finding made by the applicants is that the neurotoxic effect of a drug such as cisplatin can be reduced by pre-administering paclitaxel or a paclitaxel equivalent to a patient undergoing chemotherapy. This is surprising given that both paclitaxel and cisplatin induce significant peripheral neurotoxicity in patients when administered separately.

The mechanism of paclitaxel- induced neurotoxicity has been proposed to involve the stabilisation of microtubules (Cavaletti et al (1995)), whose integrity is important for the transport of substances up and down the very long axons of peripheral nerves. Microtubules have also been implicated in the neurotoxicity of cisplatin, through its 5 destabilising effect on these structures (Peyrot et al (1983)). Therefore, without wishing to be bound by any particular theory, the applicants believe that the protective effect is due to the opposing effects each has on the dynamic equilibrium between microtubules and tubulin.

The timing of pre-administration is an important feature of the invention. Effectively, what the applicants have found is that pre-administration of the protective compound (paclitaxel or its equivalent) should occur at least 4 hours prior to administration of the neurotoxic chemotherapeutic drug. This is believed to be a minimum time period for protection against the neurotoxic effect.

The protective compound can of course be pre-administered significantly longer than 4 hours before administration of the neurotoxic chemotherapeutic drug. It is presently contemplated that pre-administration can occur up to 72 hours prior to administration of the chemotherapeutic compound.

More usually, the pre-administration will occur from 12 to 48 hours prior to administration of the chemotherapeutic drug, still more usually 20 to 28 hours prior to administration of the chemotherapeutic drug, with an interval between administration of the protective compound and the chemotherapeutic drug of 24 hours being presently most preferred.

The presently preferred protective compound is paclitaxel (Bristol-Myers Squibb). This preference reflects the fact that paclitaxel is a potent anti-tumor agent in its own right which enhances the anti- tumor effect of the therapy. However, it is also contemplated that paclitaxel analogs and equivalents such as docetaxel (Rhone Poulenc Rorer), cryptophycins (Lilly Research Laboratories), eleutherobins (Bristol Myers Squibb), lanliamlides, epothilones (Novartis Pharma AG), benzoylphenylureas (National Cancer Institute) and solubilised conjugates of paclitaxel (Cell Therapeutics Inc) can also be employed.

Similarly, while it is presently preferred that the neurotoxic chemotherapeutic drug be cisplatin, other such compounds can also be employed. Representative of such compounds are other platinum-based anti-tumor agents such as carboplatin (Bristol Myers Squibb), oxaliplatin (Sanofi Winthrop), diaminocyclohexane platinum 6 complexes, BBR 3464 (Roche) and AMD 473 (Zeneca), and compounds such as hexamethylmelamine (US Bioscience).

The treatment compounds (paclitaxel or paclitaxel equivalent, and the non-taxane chemotherapeutic drug) will be administered to the patient at dosages which are standard in the anti-cancer art to effect an anti-tumour result. These dosages will be selected as a matter of routine skill for a practitioner in this field.

For example, a standard dosage for paclitaxel is from 135-225 mg/m², whereas a standard dosage for docetaxel is from 60- 100 mg/m³.

It is however by no means excluded that the dosages of the treatment compounds can be increased over standard dosages in order to increase the anti-tumour effectiveness of the treatment where this is considered appropriate. In accordance with the present invention, it is possible to do this without a collateral increase in peripheral neurotoxocity, and indeed, in many cases, with a lesser degree of neurotoxocity than is associated with lower dosages of the non-taxane chemotherapeutic drug when administered alone.

The invention will now be illustrated with reference to the following experimental section, which will be understood to be exemplary only.

EXPERIMENTAL

A. PACLITAXEL/ CISPLATIN

Methods

Animals Age-matched female Wistar rats (born within one week) were randomly assigned to treatment or control groups of 12 animals at 10 weeks old. For tumor growth delay studies, C57B1/6 female mice (20 ± 1 g body weight) were randomly assigned to groups of 5. The animal procedures were approved by the University of Auckland Animal Ethics Committee. 7

Drugs and Treatment

Paclitaxel was dissolved in Cremophor EL (Sigma, St Louis, MO) ethanol mix (1: 1) to make a stock solution of 6 mg/ml then further diluted with 0.9% saline to make the dosing solution at an injection volume of 10 ml/ kg. Cisplatin (Sigma, St Louis, MO) was dissolved in 0.9% sodium chloride (Baxter Healthcare, Old Toongabbie, Australia) by sonication to make a dosing solution of 10 ml/kg. Control animals were treated with the drug vehicle alone. The treatments were given by intraperitoneal injection immediately after the drug solution was made up. Treatment was given between 2 and 4 pm to avoid possible chronological effects, and repeated once per week. Paclitaxel and cisplatin were administered 24 hours apart when the drugs were given in combination in an attempt to avoid possible pharmacokinetic interactions.

Measurement of Sensory Nerve Conduction Velocity Measurements were carried out as described in McKeage et al (1994). Briefly, female Wistar rats were anaesthetised with Hypnorm (Jansen Pharmaceuticals, Oxford, UK) and placed under a 40 watt lamp. The distance between the left sciatic notch and ankle was measured. Recordings of the H-responses in the left hind limb evoked by percutaneous stimulation of the sciatic and tibial nerve were made. The H-related sensory nerve conduction (SNCV) was calculated from the difference in the latency of the H-response at the two stimulation sites and the nerve path length. The significance of differences in SNCV between the groups were assessed using a Two Factor ANOVA with post hoc Fishers Protected Least Squares Difference tests using SuperAnova software (Abacus Concepts Inc, Berkeley, CA). Differences between groups were regarded as significant when the P value was less than 0.05 (two tailed). The nature of the interaction between paclitaxel and cisplatin was assessed using an isobologram where the region of additivity was estimated from the effects of paclitaxel and cisplatin given alone by the method of Gessner (Gessner (1995)).

Measurement of dorsal root ganglia (DRG) morphological toxicity^ At the end of the experiment, L5 DRG were collected from animals sacrificed using pentobartitone (90 mg/kg) followed by an intracardiac injection of 60 mL 4% paraformaldehyde in 0.1 M phosphate buffer under terminal anaesthesia. DRG were removed and fixed in 4% buffered paraformaldehyde, dehydrated, embedded in paraffin, sectioned at 6 μm and stained with Gill's haematoxylin and Moore's eosin. 8

Other workers have shown that the major morphological change in DRG from animals treated with cisplatin is shrinkage of the nucleoli of large diameter DRG neurons (Tomiwa et al (1986)). Nucleolar diameters were determined using a method adapted from Tomiwa (supra) and Coggeshall (Coggeshall et al (1990)). Sections were randomly selected (10 sections per DRG) and the longest perpendicular diameters of the nucleoli from the 10 largest neurons per DRG measured using an ocular micrometer and an oil emersion lens at 1000 times magnification. The relationship between DRG nucleoli shrinkage and cisplatin dose was assessed using linear regression analysis. The significance of differences in the slopes of regression lines was assessed using a two-tailed t-test (Glanz (1989)). A P value of less than 0.05 (two-sided) was regarded as significant.

Measurement of tissue levels of platinum by ICP-MS.

Tissues were collected for analysis of platinum content 48 hours after the last dose of cisplatin from animals sacrificed by exsanguination under terminal pentobarbitone anaesthesia. The tissues were prepared by nitric acid digestion and analysed using a Hewlett Packard HP4500 ICP-MS as previously described (Screnci et al (1998)). The relationship between the concentrations of platinum in tissues and cisplatin dose was assessed using linear regression analysis. The significance of differences in the slopes of regression lines were assessed using a two-tailed t- test. A P value of less than 0.05 (two-sided) was regarded as significant.

Measurement of tumour growth delays in mice.

Colon 38 tumors were grown subcutaneously following implantation of 1 mm³ fragments under anaesthesia (pentobarbitone 90 mg/kg). When the tumor diameters were 4 + 1 mm, mice were injected with a single intraperitoneal (i.p.) dose of the drugs under test. Tumor diameters were measured with callipers and volumes calculated as 0.52a²b, where a and b are the minor and major tumor axes. Tumor growth delays were measured at a time when mean logarithmic tumor volumes had increased five-fold from their initial volume.

Results

SNCV was measured in animals treated with single agent or combination cisplatin and paclitaxel once per week for up to nine weeks. Paclitaxel given alone caused reductions in SNCV at doses of 12 μmol/kg/week (P=0.002) and 18 μmol/kg/week 9

(P<0.0001) after cumulative doses of 60 to 90 μmol/kg. Cisplatin alone caused reductions of SNCV at a dose of 10 μmol/kg/week (P =0.012) after a cumulative dose of 60 μmol/kg. These findings together with literature data on the effects of single agent paclitaxel and cisplatin in this animal model (Cavaletti et al (1995); De Koning et al (1987)), indicated that alterations in SNCV occurred after a cumulative dose of 57 μmol/kg (97.5% CI; 52 to 62 μmol/kg; n=20) of cisplatin and 70 μmol/kg (97.5% CV; 49 to 90 μmol/kg; n=6) of paclitaxel.

The effects of combination treatment with cisplatin and paclitaxel on SNCV were assessed in animals given cisplatin 24 hours before paclitaxel or the reverse sequence of paclitaxel 24 hours before cisplatin (Figure 1). There was a significant reduction in SNCV in animals treated with cisplatin followed 24 hours later by paclitaxel (P<0.0001) coming on after 4 to 6 weeks of treatment and cumulative doses of paclitaxel and cisplatin of 54 to 72 μmol/kg and 20 to 50 μmol/kg respectively. There was no reduction in SNCV in animals treated with paclitaxel first followed 24 hours later by cisplatin (P=0.11) even after a total of nine weeks of treatment and cumulative doses of cisplatin and paclitaxel of 45 to 60 μmol/kg and 63 to 135 μmol/kg, respectively.

The nature of the interaction between paclitaxel and cisplatin was analysed using an isobologram (Figure 2). Isoboles for combination treatment with paclitaxel and cisplatin fell outside the zone of additivity, determined from the effects of cisplatin and paclitaxel given alone according to the method of Gessner (supra) . The isobole for combination treatment with paclitaxel given 24 hours before cisplatin fell the furthest from the origin and within the antagonistic region of the isobologram.

At the end of the experiment, peripheral nerve tissues were collected for an analysis of histological toxicity and platinum content. The nucleoli diameter of large DRG neurons were significantly altered (P<0.0001) following cisplatin given alone but not following single agent pacHtaxel. The change in nucleolar size in animals treated with cisplatin given before or after paclitaxel was significantly less (P=0.004) than in animals given cisplatin alone (Figure 3).

Inductively coupled plasma mass spectrometry analysis of DRG, sciatic nerves and sural nerves collected at the end of the experiment from animals treated with cisplatin alone revealed a relationship between the cumulative dose of cisplatin and 10 the concentrations of platinum in DRG (P=0.0003), sural nerve ( =0.0027) and sciatic nerve (P=0.002). The slope of the regression lines describing the relationship for cisplatin alone was not significantly different from the regression slopes for cisplatin given in conjunction with pacHtaxel.

To control for the possibifity that the antitumor effects of pacHtaxel and cisplatin were antagonistic when used on this schedule, C57B16 mice bearing colon 38 tumors were treated with pacHtaxel (23.4 μmol/kg) foUowed 24 hours later by cisplatin (23.3 μmol/kg) or by pacHtaxel (23.4 μmol/kg) and cisplatin (23.3 μmol/kg) given alone. Tumor growth delays were greater after pacHtaxel foUowed by cisplatin (7.5 days) than when pacHtaxel (2.0 days) or cisplatin (3.5 days) were given alone (Figure 4).

Discussion

The above results show that pacHtaxel and cisplatin given in combination eficited an antagonistic drug interaction resulting in lower toxicity to the peripheral nervous system than either agent given alone. Both pacHtaxel and cisplatin caused changes in SNCV when given to Wistar rats as single agents, but their effects on SNCV were less- than additive when they were given in combination. Cisplatin-induced alterations in the size of nucleoH of DRG neurons were less marked when cisplatin was given in conjunction with pacHtaxel than when cisplatin was given alone. This provides evidence for pacHtaxel and cisplatin counteracting each other's toxicity to the peripheral nervous system, and provides the basis for a new strategy for protecting peripheral nerves from chemotherapy toxicity involving the addition of a second cytotoxic agent to oppose the neurotoxicity of the first.

A potential advantage over other neuroprotective approaches of using combinations of cytotoxic drugs to minimise neurotoxicity is the expectation of additive or greater- than-additive antitumor activity. In the results reported above the antitumor effects of pacHtaxel and cisplatin in C57B1 mice bearing colon 38 tumors were at least additive when the agents were deHvered on a dosing schedule that antagonised each others neurotoxicity. The combination of pacHtaxel and cisplatin has also been associated with improvements in the survival of patients with ovarian cancer (McGuire et al (1996)). Together, these findings suggest that combining pacHtaxel 1 1 and cisplatin to counteract their peripheral neurotoxicity would also result in enhanced antitumor activity.

It is possible that the mechanism of the neuroprotective interaction between pacHtaxel and cisplatin involves their opposing effects on the dynamic equiHbrium between microtubules and tubulin within peripheral nerves. Microtubule structures play a key role in the transport of substances up and down the very long axons of peripheral nerves. The mechanism of neurotoxicity induced by pacHtaxel has been proposed to involve the formation of abnormaUy large and stable microtubule structures within peripheral nerves leading to disturbed axonal transport (Cavaletti et al (1995)). Conversely, cisplatin could disturb axonal transport by inducing intraneuronal Ca²⁺ overload (Scott et al (1995)), depolymerisation of microtubules and formation of abnormally small microtubule structures (Peyrot et al (1983)). The net change in microtubule size may be less when pacHtaxel and cisplatin are given in combination because of their opposing effects on microtubule dynamics.

Conclusion

In conclusion, a pharmacodynamic interaction between pacHtaxel and cisplatin aUowed the minimisation of their toxicity to the peripheral nervous system. The reduction in neurotoxicity was unlikely to have resulted from a pharmacokinetic interaction since the concentrations of platinum in DRG, sural nerves and sciatic nerves were not altered by the co-administration of pacHtaxel, and the antitumor activity of the combination was greater than for the single agents.

B. DOCETAXEL/ OXALIPLATIN

This experiment was to test whether the protective effect is, or is not, specific to the pacHtaxel-cisplatin combination.

Materials and Methods

Animals and treatments Female Wistar rats aged 10 weeks old were randomly allocated to treatment and control groups. The animals were age-matched in that they were all born within one 12 week. Fresh drug solutions were made up on each day of treatment. OxaHplatin was dissolved in sterile 0.9% NaCl and given intraperitoneally at a dose of 5 μmol/kg in an injection volume of 10 ml/kg. Docetaxel was dissolved in Tween 80/ethanol before being diluted in 0.9% NaCl. The final dosing solution of docetaxel contained 0.5% (v/v) Tween 80 and 0.2% (v/v) ethanol. Docetaxel was given intraperitoneally at a dose of 2.5 μmol/kg in an injection volume of 10 ml/kg. Animals receiving oxaHplatin in combination with docetaxel were given docetaxel first foUowed 24 hours later by oxaHplatin. Animals receiving oxaHplatin alone were given the docetaxel drug vehicle foUowed 24 hours by oxaHplatin. The control animals were given the docetaxel drug vehicle foUowed 24 hours later by the oxaHplatin drug vehicle. Treatment was repeated once per week for 10 weeks.

Measurement of sensory nerve condition velocity

SNCV was measured weekly as described in Section A.

Assessment of dorsal root ganglia (DRG) shrinkage

OxaHplatin- induced DRG morphometric changes were assessed at 6 and 10 weeks as described in Section A.

Results

Effect on sensory nerve condition velocity

The effects of oxaHplatin alone and oxaHplatin given in combination with docetaxel were compared in two independent experiments (Figure 5). Animals were treated with oxaHplatin alone (5 μmol/kg per week), docetaxel (2.5 μmol/kg per week) foUowed 24 hours later by oxaHplatin (5 μmol/kg per week) or drug vehicle alone on a once per week dosing schedule for ten weeks. Measurements of SNCV were made once per week. SNCV determinations in the treatment groups were expressed as a percentage of SNCV in the control group.

OxaHplatin alone induced a decrease in SNCV by approximately 15% after a cumulative dose of 30 μmol/kg (Figure 5). Changes in SNCV associated with oxaHplatin given in combination with docetaxel were less marked. A 15% decrease in SNCV was not seen until a cumulative oxaHplatin dose of 45 μmol/kg had been administered when oxaHplatin was combined with docetaxel. 13

Effect on DRG shrinkage

Five animals from each group were sacrificed at 6 and 10 weeks under terminal pentobarbitone anaesthesia for an analysis of oxaHplatin-induced DRG morphological toxicity. At six weeks and a cumulative oxaHplatin dose of = 30μmol/kg, there was a statisticaUy significant change in the nucleolar diameter of DRG neurons in animals treated with oxaHplatin alone (nucleolar shrinkage, 41.2 ± 0.4% of control, P < 0.0001). OxaHplatin-induced DRG morphometric changes in animals treated with oxaHplatin combined with docetaxel were significantly less (nucleolar shrinkage, 30.6 ± 5.9% of control) than when oxaHplatin was given alone (P = 0.028). After 10 weeks and a cumulative oxaHplatin dose of 50 μmol/kg, DRG morphometric changes were similar in both groups (P = 0.7).

Discussion

The above results show that the peripheral nerve effects of oxaHplatin in combination with docetaxel were less than was expected from the effects of oxaHplatin given alone after 6 to 8 weeks of treatment using a once per week dosing schedule. The results suggest that docetaxel reduces oxaHplatin-induced damage to the peripheral nervous system of rats when the agents are administered using a 24 hours dosing interval and the sequence of docetaxel foUowed by oxaHplatin.

General Conclusion

The results, together with those reported above, provide evidence for the general effect of taxane and platinum drugs cancelling out each others neurotoxicity. The results of section A demonstrated that pacHtaxel and cisplatin antagonised each others neurotoxicity on a dosing schedule associated with greater than additive in vivo anti-tumour activity. The results in section B and C showed less oxaHplatin- induced neurotoxicity when oxaHplatin was given in conjunction with docetaxel than was expected from the effects of oxaHplatin given alone. Taken together, these results demonstrate that neuroprotective interactions are a common property among different analogues of the taxane and platinum classes of cancer chemotherapeutic agents. 14

INDUSTRIAL APPLICATION

The present invention provides a method by which one of the major adverse side effects of chemotherapeutic drugs (neurotoxicity) can be ameUorated without compromising the anti-tumour effectiveness of the treatment. The result is achieved by pre-administration of a protective taxane compound a minimum of 4 hours prior to administration of the neurotoxic chemotherapeutic compound.

The protective interaction between the compounds aUows dosages of chemotherapeutic compounds to be administered which deHver an efficacious anti- tumour result but without the usual degree of peripheral neurotoxicity to the patient. This increases patient tolerance of the treatment.

In addition, the protective interaction provides the opportunity to administer even higher dosages of chemotherapeutic compounds to patients to increase the anti- tumour effect but without increasing peripheral neurotoxicity beyond levels currently tolerated with lower dosages. Thus, the anti-tumour effectiveness of the treatment can be increased where appropriate but without the coUateral sacrifice in terms of increased peripheral neurotoxicity being required.

Other appHcations and impHcations of the present method wiU be apparent to those persons skilled in the cancer treatment art.

It wiU also be appreciated by those persons that the above description and experimental work is illustrative only and that the invention is not to be regarded as limited to the specific embodiments described.

15 References

McGuire, W.P., Hoskins, W.J., Brady, M.F., Kugera, P.R., Partridge, E.E., Look, K.Y., Clarke- Pearson, D.L., and Davidson, M. Cyclophosphamide and cisplatin compared with pacHtaxel and cisplatin in patients with stage III and stage IV ovarian cancer. New Engl. J. Med., 334: 1-6, 1996.

ConneUy, E., Markman, M., Kennedy, A., Webster, K., Kulp, B., Peterson, G., and Belinson, J. PacHtaxel deHvered as a 3-hr infusion with cisplatin in patients with gynecologic cancer: Unexpected incidence of neurotoxicity. Gynecol. Oncol. 62: 166- 168, 1996.

Gordon, A.N., Stringer, C.A., Matthews, CM., WiUis, D.I., and Nemunaitis, J. Phase I escalation of pacHtaxel in patients with advanced ovarian cancer receiving cisplatin: Rapid development of neurotoxicity is dose-Hmiting. J. CHn. Oncol., 15: 1965- 1973, 1997.

Cassidy, J., Paul, J., Soukop, M., Habeshaw, T., Reed, N.S., Parkin, D., and Kayes, S.B. Clinical trials of nimodipine as a potential neuroprotector in ovarian cancer patients treated with cisplatin. Cancer Chemoth. Pharm. 41: 161- 166, 1998.

Roberts, J.A., Jenison, E.L., Kim, K.M., Clarke-Pearson, D., and Langlebean, A. A randomized, multicentre, double-blind, placebo-controUed dose-finding study of ORG 2766 in the prevention or delay of cisplatin-induced neuropathies in women with ovarian cancer. Gynecol. Oncol., 67: 172- 177, 1997.

Kemp, G., Rose, P., Lurain, J., Berman, M., Manetta, A., RouUet, B., Homesley, H., Belpomme, D., and GHck, J. Amifostine pretreatment for protection against cyclophosphamide-induced and cisplatin-induced toxicities: Results of a randomised controUed trial in patients with advanced ovarian cancer. J. CHn. Oncol., 14: 2101-2112, 1996.

Cavaletti, G., Tredici, G., Braga, M., and Tazzari, S. Experimental peripheral neuropathy induced in adult rats by repeated intraperitoneal administration of taxol. Exp. Neurol., 133: 64-72, 1995. 16

Peyrot, V., Briand, C, Crevat, A., Braguer, D., Chauvet-Monges, A.M., and Sari, J.C Action of hydrolysed cisplatin and some analogs on microtubule protein polymerization in vitro. Cancer Treat. Rep., 67: 641-646, 1983.

De Koning, P., Neijt, J.P., Jennekens, F.G.I. , and Gispen, W.H. Evaluation of cis- diamminedichloroplatinum(II) (cisplatin) neurotoxicity in rats. Toxicol. Appl. Pharm., 59: 81-87, 1987.

Tomiwa, K., Nolan, C, and Cavanagh, J.B. The effects of cisplatin on rat spinal gangHa: a study by Hght and electron microscopy and by morphometiy. Acta. Neuropathol., 69: 295-308, 1986.

McKeage, M.J., BoxaU, F., Jones, M., and Harrap, K.R. Lack of neurotoxicity of oral bis-acetato-aπιnιine-dichloro-cyclohexylamine-platinum(IV) (JM216) in comparison to cisplatin and tetraplatin in the rat. Cancer Res., 54: 629-631, 1994.

Gessner, P.K. Isobolographic analysis of interactions: an update on appHcations and utiHty. Toxicology, 105: 161- 179, 1995.

CoggeshaU, R.E., La Forte, R., and Klein, CM. CaHbration of methods for determining numbers of dorsal root gangHa ceUs. J. Neurosci. Meth., 35: 187- 194, 1990.

Glantz, S.A. Primer of Biostatistics. 2nd ed. Singapore: McGraw-HiU, 1989.

Screnci, D., Galettis, P., Baguley, B.C., and McKeage, M.J. Optimization of an ICP- MS assay for the detection of trace levels of platinum in peripheral nerves. Atomic Spectrosc, 19: 172- 175, 1998.

Scott, R.H., Woods, A.J., Lacey, M.J., Fernando, D., Crawford, J.H., and Andrews, P.L.R. An electrophysiological investigation of the effects of cisplatin and the protective actions of dexamethasone on cultured dorsal root neurones from neonatal rats. N-S Arch. Pharmacol., 352: 247-255, 1995.

Claims

17 CLAIMS

1. A method for reducing neurotoxicity symptoms in a patient suffering from cancer and undergoing therapy with a non-taxane neurotoxic chemotherapeutic drug whUe maintaining the anti-tumor effectiveness of said drug, which method comprises the step of administering to said patient an effective amount of pacHtaxel or of a pacHtaxel equivalent between 4 and 72 hours prior to administration of said neurotoxic chemotherapeutic drug.

2. A method according to claim 1 wherein the neurotoxicity symptoms are peripheral neurotoxicity symptoms.

3. A method according to claim 1 or claim 2 wherein the neurotoxic chemotherapeutic drug is a platinum-based chemotherapeutic drug or is hexamethylmelamine.

4. A method according to claim 3 wherein the platinum-based chemotherapeutic drug is cisplatin or a cisplatin analog or derivative.

5. A method according to claim 3 wherein the platinum-based chemotherapeutic drug is selected from carboplatin, diaminocylohexane platinum complexes, BBR 3464 or AMD 473.

6. A method according to claim 3 wherein the platinum-based chemotherapeutic drug is oxaHplatin.

7. A method according to any preceding claim wherein the compound which is preadministered is pacHtaxel.

8. A method according to any one of claims 1 to 6 wherein the compound is selected from cryptophycins, eleutherobins, lanHamHdes, epothUones, benzoylphenylureas and solubiHsed conjugates of pacHtaxel.

9. A method according to any one of claims 1 to 6 wherein the compound which is preadministered is docetaxel. 18

10. A method according to any preceding claim wherein the pacHtaxel or pacHtaxel equivalent is administered from 12 to 48 hours prior to administration of the neurotoxic chemotherapeutic drug.

11. A method according to any one of claims 1 to 9 wherein the pacHtaxel or pacHtaxel equivalent is administered from 20 to 28 hours prior to administration of said neurotoxic chemotherapeutic drug.

12. A method according to any one of claims 1 to 9 wherein the pacHtaxel or pacHtaxel equivalent is administered about 24 hours prior to administration of said neurotoxic chemotherapeutic drug.

13. A method according to claim 1 wherein said neurotoxic chemotherapeutic drug is oxaHplatin and the compound which is pre-administered is pacHtaxel or docetaxel.

14. A method according to claim 13 wherein said pacHtaxel or docetaxel is administered about 24 hours prior to the administration of oxaHplatin.

15. The use of pacHtaxel or a pacHtaxel equivalent in the preparation of a medicament for reducing peripheral neurotoxicity symptoms associated with subsequent administration of a non-taxane neurotoxic chemotherapeutic drug to a patient undergoing cancer therapy.

16. The use of claim 15 wherein the use is of pacHtaxel.

17. The use of claim 15 wherein the use is of docetaxel.

18. The use of claim 16 or claim 17 wherein the neurotoxic chemotherapeutic drug is oxaHplatin.