Methods for treating a non-spasm caused pain by peripheral administration to a patient of a therapeutically effective amount of a neurotoxin, such as a botulinum toxin.

SUMMARY OF THE INVENTION

The present invention meets this need and provides an effective, long lasting, non-surgical method to treat pain, particularly pain which is not associated with a muscle disorder or headache.

A method within the scope of the present invention for treating pain can comprise the step of peripheral administration of a neurotoxin to a mammal. The pain treated is not associated with a muscle disorder, such as a muscle spasm, because it is believed that a mechanism by which the present invention works is by an antinociceptive effect upon peripheral, sensory afferent pain neurons, as opposed to having an effect upon motor neurons.

The neurotoxin can comprise a neuronal binding moiety which is substantially native to the neurotoxin. The neurotoxin can be a botulinum toxin, such as one of the botulinum toxin types A, B, C.sub.1, D, E, F or G. Preferably the botulinum toxin is botulinum toxin type A.

The neurotoxin can be a modified neurotoxin which has at least one amino acid deleted, modified or replaced. Additionally, the neurotoxin can be made at least in part by a recombinant process.

The neurotoxin can be administered in an amount between about 0.01 U/kg and about 35 U/kg and the pain treated can be substantially alleviated for between about 1 month and about 27 months, for example for from about 1 month to about 6 months.

The peripheral administration of the neurotoxin can be carried out prior to an onset of a nociceptive event or syndrome experienced by a patient. Additionally, the peripheral administration of the neurotoxin can be carried out subsequent to an onset of a nociceptive event experienced by a patient.

A detailed embodiment of a method within the scope of the present invention can comprise the step of peripheral administration of a botulinum toxin to a human patient, thereby alleviating pain, wherein the pain is not associated with a muscle spasm or with a headache.

A further method within the scope of the present invention can comprise the step of peripheral administration of a neurotoxin to a mammal, wherein the neurotoxin is a polypeptide comprising: (a) a first amino acid sequence region comprising a wild type neuronal binding moiety, substantially completely derived from a neurotoxin selected from a group consisting botulinum toxin types A, B, C.sub.1, D, E, F, G and mixtures thereof; (b) a second amino acid sequence region effective to translocate the polypeptide or a part thereof across an endosome membrane, and; (c) a third amino acid sequence region having therapeutic activity when released into a cytoplasm of a target cell, wherein the pain is not associated with a muscle spasm.

The first amino acid sequence region of the polypeptide can comprise a carboxyl terminal of a heavy chain derived from the neurotoxin and the neurotoxin can be a botulinum toxin, such as botulinum toxin type A.

The second amino acid sequence region of the polypeptide can have an amine terminal of a heavy chain derived from a neurotoxin selected from a group consisting of botulinum toxin types A, B, C.sub.1, D, E, F, G and mixtures thereof. Notably, the second amino acid sequence region of the polypeptide can include an amine terminal of a toxin heavy chain derived from botulinum toxin type A.

Finally, the third amino acid sequence region of the polypeptide can comprise a toxin light chain derived from a neurotoxin selected from a group consisting of Clostridium beratti toxin; butyricum toxin; tetani toxin; botulinum toxin types A, B, C.sub.1, D, E, F, G and mixtures thereof. The third amino acid sequence region of the polypeptide can include a toxin light chain derived from botulinum toxin type A.

The present invention also includes a method for improving patient function, the method comprising the step of peripheral administration of a botulinum toxin to a patient experiencing a non-muscle disorder related pain, thereby improving patient function as determined by improvement in one or more of the factors of reduced pain, reduced time spent in bed, improve hearing, increased ambulation, healthier attitude and a more varied lifestyle.

Significantly, the neurotoxins within the scope of the present invention comprise a native or wild type binding moiety with a specific affinity for a neuronal cell surface receptor. The neurotoxins within the scope of the present invention exclude neuronal targeting moieties which are not native to the neurotoxin because we have found that the present invention can be effectively practiced without the necessity of making any modification or deletions to the native or wild type binding moiety of the neurotoxins used.

Thus, use of a neurotoxin with one or more non-native, targeting moiety artifacts or constructs is excluded from the scope of the present invention as unnecessary because, as stated, we have surprisingly discovered that peripheral administration of a neurotoxin according to the present invention provides significant pain alleviation even though the neurotoxin does not comprise a non-native neuronal targeting moiety. Thus we have discovered that a neurotoxin, such as botulinum toxin type A, can upon peripheral administration provide alleviation of pain even though the neurotoxin has not been artificially or manipulatively accorded any attachment of a non-native neuronal targeting moiety.

Surprisingly, we have discovered that a neurotoxin, for example a Clostridial neurotoxin, having a wild type neuronal binding moiety can be peripherally administered into a mammal to treat pain. The wild type neuronal binding moiety is originally part of the neurotoxin. For example, botulinum toxin type A, with its original wild type neuronal binding moiety can be administered peripherally in amounts between about 0.01 U/kg to about 35 U/kg to alleviate pain experienced by a mammal, such as a human patient. Preferably, the botulinum toxin used is peripherally administered in an amount between about 0.1 U/kg to about 3 U/kg. Significantly, the pain alleviating effect of the present disclosed methods can persist for an average of 1 6 months and longer in some circumstances. It has been reported that an effect of a botulinum toxin can persist for up to 27 months after administration.

In another embodiment, the method of treating pain comprises administering to a mammal a neurotoxin, for example a Clostridial neurotoxin, wherein the neurotoxin differs from a naturally occurring neurotoxin by at least one amino acid. The neurotoxin also has a wild type neuronal binding moiety.

In another embodiment, the methods of treating pain comprises administering to a mammal a neurotoxin, for example a Clostridial neurotoxin, wherein the neurotoxin has a wild type neuronal binding moiety of another neurotoxin subtype.

The present invention also includes a method for treating a post-operative pain where the pain is a result of the surgical procedure carried out (i.e. the pain is due, at least in part, to the incisions made). The method can comprise the step of peripheral administration of an effective amount of a botulinum toxin before (i.e. up to 10 days before the surgery), during or immediately after (i.e. by no later than about 6 12 hours after the surgery) a surgical procedure, thereby alleviating or significantly alleviating a post-operative pain. The scope of our invention does not include a method wherein th surgical procedure is carried out to treat a muscle spasm.

Our invention also includes a method for treating a visceral pain by a non-systemic, local administration of an effective amount of a botulinum toxin to thereby alleviate the visceral pain. A visceral pain is a pain which is perceived by the patient to arise from a site in the viscera, that is in an organ of the digestive, respiratory, urogenital, and endocrine systems, as well in the spleen, heart and/or vessels. Thus, visceral pain includes pain in the pancreas, intestine, stomach and abdominal muscles.

A preferred method within the scope of the present invention for treating pain comprises the step of peripheral administration of a neurotoxin to a mammal. The pain treated is not substantially due to a muscle spasm because we have surprisingly discovered that a neurotoxin within the scope of the present invention can be used to treat pain which is not secondary to a muscle spasm. Thus, the present invention is applicable to the treatment of pain which arises irrespective of the present or absence of a muscle disorder, such as a muscle spasm. Additionally, the present invention is also applicable to and includes within its scope, the treatment of pain which is not secondary to a muscle spasm. Thus, a patient can have a spasmodic or hypertonic muscle and also experience pain which is not secondary, that is does not arise from or is not due to, to the muscle spasm. For example, a patient can have a spasmodic limb muscle and concurrently experience pain in the truck, such as a back pain. In this example, a method within the scope of the present invention can treat the back pain by peripheral (i.e. subcutaneous) administration of a neurotoxin to the patient's back.

DESCRIPTION OF THE INVENTION

The present invention is based on the discovery that peripheral administration of a neurotoxin can provide effective treatment of chronic pain. Notably, the neurotoxin has a wild type or native neuronal binding moiety. The pain treated is not due to a muscle spasm, nor is the pain headache pain. Chronic pain is treated because of the long term antinociceptive effect of the neurotoxins used. The neuronal binding moiety component of the neurotoxin is a neuronal binding moiety which is native to the selected neurotoxin because we have discovered that the present invention can be practiced without replacement of the wild type neuronal binding moiety with a non-native or non wild type targeting moiety. Treatment of headache pain is not within the scope of the present invention because the preferred sites of peripheral administration of a neurotoxin according to the present invention exclude the head and neck.

Prior to our discovery a neurotoxin, such as a botulinum toxin, has been used to treat pain associated with various muscle disorders. Thus, it is known that a muscle disorder, such as a spasmodic muscle, can cause pain and that by treating the spasm the pain can also be alleviated. Foster et al. discloses that the neurotoxin be linked to a targeting moiety for use in the treatment of pain, that is that the wild type binding moiety of a Clostridial neurotoxin be removed completely, and replaced by a targeting moiety.

Surprising we have discovered that a neurotoxin which has not been conjugated, attached, adhered to or fused with a neuronal targeting moiety can be peripherally administered according to the methods of the present invention to treat pain. Preferably, the pain treated is not due, that is the pain does not directly arise from as a secondary result of, a muscle spasm. Our invention can be used to treat pain which results from a wide variety of neuropathic, inflammatory, cancerous and trauma conditions.

Prior to our invention is was not known that a neurotoxin, such as a botulinum toxin, could be used to effectively treat pain, where the pain is not due to a muscle spasm or hypertonic muscle condition. The physiological mechanism by which peripheral administration of a neurotoxin can result in long term alleviation of pain is unclear. We note that whereas the pain due to a muscle spasm or hypertonic muscle condition can produce a reduced, local pH, our invention does not rest upon and does not require elevation of a local, low pH level. Additionally, whereas a muscle spasm or hypertonic muscle condition can be alleviated by an anticholinergic effect of a neurotoxin, such as a botulinum toxin, upon motor neurons, our invention is not predicated upon an effect upon motor neurons. Without wishing to be bound by theory, we hypothesize, that one effect of peripheral administration of a neurotoxin, such as a botulinum toxin, according to the present invention can be an antinociceptive effect upon a peripheral, sensory afferent neuron. Significantly, in our invention pain alleviation is a primary, as opposed to being a secondary, effect upon peripheral administration of a neurotoxin, such as a botulinum toxin.

Thus, the present invention is based, at least in part, upon the discovery that a neurotoxin having a wild type neuronal binding moiety may be peripherally administered to a mammal to alleviate pain. The neurotoxin according to this invention is not coupled to a non-native targeting moiety. A wild type binding moiety according to the present invention can be a naturally existing H.sub.C segment of a Clostridial neurotoxin or an amino acid sequence substantially completely derived from the H.sub.C segment of the Clostridial neurotoxin.

As used hereinafter, an amino acid sequence, for example a wild type binding moiety, "derived from" another amino acid sequence, for example the H.sub.C segment, means that the resultant amino acid sequence is duplicated exactly like the amino acid sequence from which it is derived; or the resultant amino acid sequence has at least one amino acid deleted, modified or replaced as compared to the amino acid sequence from which it is derived.

According to one broad aspect of the invention, there are provided methods for treatment of pain which comprise administering to a mammal effective doses of a neurotoxin, for example a Clostridial neurotoxin, having a wild type n uronal binding moiety. In one embodiment, the methods include administering to a mammal a neurotoxin having a wild type neuronal binding moiety which is originally already a part of the neurotoxin. For example, such neurotoxin may be selected from a group consisting of beratti toxin and butyricum toxin, each of which already has a neuronal binding moiety. The neurotoxin may also be a tetani toxin, which also has a wild type neuronal binding moiety. Preferably, the neurotoxin administered to the mammal is selected from a group consisting of botulinum toxin types A, B, C.sub.1, D, E, F, or G, each of which has its own original wild type neuronal binding moiety. More preferably, the methods include the administration of botulinum type A with its original wild type neuronal binding moiety. The methods also include the administration of a mixture of two or more of the above neurotoxins to a mammal to treat pain.

In another embodiment, the methods comprise the administration of a neurotoxin, for example a Clostridial neurotoxin, to a mammal wherein the neurotoxin differs from a naturally occurring neurotoxin by at least one amino acid. For example, variants of botulinum toxin type A as disclosed in Biochemistry 1995, 34, pages 15175 15181 and Eur. J. Biochem, 1989, 185, pages 197 203 (incorporated herein by reference in its entirety) may be administered to a mammal to treat non-spasm related pain. These variants also have wild type neuronal binding moieties.

In another embodiment, methods are provided for an administration of a neurotoxin to a mammal to treat non-spasm caused pain, wherein the neurotoxin has a wild type neuronal binding moiety of another neurotoxin. For example, the method includes the step of administering to a mammal botulinum toxin type A having a wild type neuronal binding moiety of botulinum toxin type B. All other such combinations ar included within the scope of the present invention.

In another broad embodiment, methods of the present invention to treat non-spasm related pain include local, peripheral administration of the neurotoxin to an actual or a perceived pain location on the mammal. In one embodiment, the neurotoxin is administered subcutaneously at or near the location of the perceived pain, for example at or near a chronically painful joint. In another embodiment, the neurotoxin is administered intramuscularly at or near the location of pain, for example at or near a neoplasm on the mammal. In another embodiment, the neurotoxin is injected directly into a joint of a mammal, for treating or alleviating pain causing arthritic conditions. Also, frequent, repeated injections or infusion of the neurotoxin to a peripheral pain location is within the scope of the present invention. However, given the long lasting therapeutic effects of the present invention, frequent injections or infusion of the neurotoxin may not be necessary. For example, practice of the present invention can provide an analgesic effect, per injection, for 2 months or longer, for example 7 months, in humans.

Without wishing to limit the invention to any mechanism or theory of operation, it is believed that when the neurotoxin is administered locally to a peripheral location, it inhibits the release of neuro-substances, for example substance P, from the peripheral primary sensory terminal. As discussed above, a release of substance P by the peripheral primary sensory terminal may cause or at least amplify pain transmission process. Therefore, inhibition of its release at the peripheral primary sensory terminal will dampen the pain transmission process.

In addition to having pharmacologic actions at a peripheral location of administration, a method within the scope of the present invention may also have an antinociceptive effect due to retrograde transport to the neurotoxin from the site of peripheral (i.e. subcutaneous) injection to the central nervous system. We have determined that botulinum type A can be retrograde transported from the peripheral site of administration back to the dorsal horn of the spinal cord. Presumably the retrograde transport is via the primary afferent. This finding is consistent with the work by Weigand et al, Nauny-Schmiedeberg's Arch. Pharmacol. 1976; 292, 161 165, and Habermann, Nauny-Schmiedeberg's Arch. Pharmacol. 1974; 281, 47 56, which show d that botulinum toxin is able to ascend to the spinal area by retrograde transport. Thus, it was reported that botulinum toxin type A injected intramuscularly may be retrograde transported from the peripheral primary sensory terminal to the central primary sensory terminal.

Our discovery differs significantly from the discussion in the articles cited in the paragraph above. We have discovered that, in the rat, after peripheral, subcutaneous administration botulinum toxin was found localized in the animal's dorsal horn, that is at the location where the C fibers synapse. A subcutaneous injection is an injection at a location where many bipolar nociceptive nerve fibers are located. These sensory fibers run from the periphery to the dorsal horn of the spinal cord. Contrarily, in one or more of the articles cited in the paragraph above after intramuscular toxin injection was carried out some radioalabelled botulinum toxin was found localized in the ventral roots. The ventral root of the spinal cord is where monopolar efferent (traffic out) motor neurons are located. Thus, the art leads to an expectation that peripheral muscle spasticity can be expected as a result of retrograde transport of a botulinum toxin from the periphery to a spinal cord location.

Thus, it had been believed by those skilled in the art that the appearance of a neurotoxin, such as a botulinum toxin in the spinal cord of a mammal would: (1) induce significant spasticity in the recipient, and; (2) promote detrimental effects upon spinal cord and brain functions. Thus, with regard to cited deleterious effect (1): it was reported, as examples, in Williamson et al., in Clostridial Neurotoxins and Substrate Proteolysis in Intact Neurons, J. of Biological Chemistry 271:13; 7694 7699 (1996) that both tetanus toxin and botulinum toxin type A inhibit the evoked release of the neurotransmitters glycine and glutamate from fetal mice spinal cord cell cultures, while it was reported by Hagenah et al., in Effects of Type A Botulinum Toxin on the Cholinergic Transmission at Spinal Renshaw Cells and on the Inhibitory Action at Ia Inhibitory Interneurones, Naunyn-Schmiedeberg's Arch. Pharmacol. 299, 267 272 (1977), that direct intraspinal injection of botulinum toxin type A in experimentally prepared, anaesthetized cats inhibits CNS Renshaw cell activity. Inhibition of central glycine and glutamate neurotransmitter release as well as the downregulation of Renshaw cell activity presumably can both result in vivo in the promotion of significant motorneuron hyperactivity with ensuing peripheral muscle spasticity.

With regard to deleterious effect (2): it is believed that central (spinal cord) presence of a tetanus neurotoxin exerts, by retrograde movement of the tetanus toxin along CNS neurons, significant negative effects upon spinal cord and brain functions, thereby contraindicating any desire to have a related neurotoxin, such as a botulinum toxin appear (as by retrograde transport) in the spinal cord. Notably, botulinum toxin and tetanus toxin are both made by Clostridial bacteria, although by different species of Clostridium. Significantly, some researchers have reported that botulinum toxin shares, at least to some extent, the noted neural ascent characteristic of tetanus toxin. See e.g. Habermann E., .sup.125I-Labeled Neurotoxin from Clostridium Botulinum A: Preparation, Binding to Synaptosomes and Ascent in the Spinal Cord, Naunyn-Schmiedeberg's Arch. Pharmacol. 281, 47 56 (1974).

Our invention surprisingly encounters neither of the deleterious effects (1) or (2), and the disclosed peripheral (subcutaneous) administration methods of the present invention can be practiced to provide effective and long lasting relief from pain which is not due to a muscle spasm and to provide a general improvement in the quality of life experienced by the treated patient. The pain experienced by the patient can be due, for example, to injury, surgery, infection, accident or disease (including cancer and diabetes), including neuropathic diseases and disorders, where the pain is not primarily due to a muscle spasm or hypertonic muscle condition.

Once in the central primary sensory terminal located in the dorsal horn of the spinal chord, the neurotoxin may further inhibit the release of the n urotransmitter responsible for the transmission of pain signals, for example substance P. This inhibition prevents the activation of the projection neurons in the spinothalamic tract and thereby alleviating pain. Therefore, the peripheral administration of the neurotoxin, due to its now discovered central antinociceptive effect, serve as an alternative method to central (i.e. intraspinal) administration of an analgesic, thereby eliminating the complications associated with central administration of an analgesic drug.

Furthermore, it has been shown by Habermann Experientia 1988; 44:224 226 that botulinum toxin can inhibit the release of noradrenalin and GABA from brain homogenates. This finding suggests that botulinum toxin can enter into the adrenergic sympathetic nerve terminals and GABA nerve terminals. As such, botulinum toxin can be administered to the sympathetic system to provide long term block and alleviate pain, for example neuropathic pain. The administration a neurotoxin, preferably botulinum toxin type A, provides a benefit of long term block without the risk of permanent functional impairment, which is not possible with pharmaceutics currently in use.

The amount of the neurotoxin administered can vary widely according to the particular disorder being treated, its severity and other various patient variables including size, weight, age, and responsiveness to therapy. For example, the extent of the area of peripheral pain is believed to be proportional to the volume of neurotoxin injected, while the quantity of the analgesia is, for most dose ranges, believed to be proportional to the concentration of neurotoxin injected. Furthermore, the particular location for neurotoxin administration can depend upon the location of the pain to be treated.

Generally, the dose of neurotoxin to be administered will vary with the age, presenting condition and weight of the mammal to be treated. The pot ncy of the neurotoxin will also be considered.

In one embodiment according to this invention, the therapeutically effective doses of a neurotoxin, for example botulinum toxin type A, at a peripheral location can be in amounts between about 0.01 U/kg and about 35 U/kg. A preferred range for administration of a neurotoxin having a wild type neuronal binding moiety, such as the botulinum toxin type A, so as to achieve an antinociceptive effect in the patient treated is from about 0.01 U/kg to about 35 U/kg. A more preferred range for peripheral administration of a neurotoxin, such as botulinum toxin type A, so as to achieve an antinociceptive effect in the patient treated is from about 1 U/kg to about 15 U/kg. Less than about 0.1 U/kg can result in the desired therapeutic effect being of less than the optimal or longest possible duration, while more than about 2 U/kg can still result in some symptoms of muscle flaccidity. A most preferred range for peripheral administration of a neurotoxin, such as the botulinum toxin type A, so as to achieve an antinociceptive effect in the patient treated is from about 0.1 U/kg to about 1 U/kg.

Although examples of routes of administration and dosages are provided, the appropriate route of administration and dosage are generally determined on a case by case basis by the attending physician. Such determinations are routine to one of ordinary skill in the art (see for example, Harrison's Principles of Internal Medicine (1998), edited by Anthony Fauci et al., 14.sup.th edition, published by McGraw Hill). For example, the route and dosage for administration of a neurotoxin according to the present disclosed invention can be selected based upon criteria such as the solubility characteristics of the neurotoxin chosen as well as the intensity of pain perceived.

In another broad embodiment of the invention, there are provided methods for treating non-spasm related pain which comprises administering effective doses of a neurotoxin, wherein the neurotoxin is a single polypeptide as opposed to a di-polypeptide as described above.

In one embodiment, the neurotoxin is a single polypeptide having three amino acid sequence regions. The first amino acid sequence region includes a neuronal binding moiety which is substantially completely derived from a neurotoxin selected from a group consisting of beratti toxin; butyricum toxin; tetani toxin; botulinum toxin types A, B, C.sub.1, D, E, F, and G. Preferably, the first amino acid sequence region is derived from the carboxyl terminal of a toxin heavy chain, H.sub.C. More preferably, the first amino acid sequence region is derived from the H.sub.C of botulinum toxin type A.

The second amino acid sequence region is effective to translocate the polypeptide or a part thereof across an endosome membrane into the cytoplasm of a neuron. In one embodiment, the second amino acid sequence region of the polypeptide comprises an amine terminal of a heavy chain, H.sub.N, derived from a neurotoxin selected from a group consisting of beratti toxin; butyricum toxin; tetani toxin; botulinum toxin types A, B, C.sub.1, D, E, F, and G. Preferably, the second amino acid sequence region of the polypeptide comprises an amine terminal of a toxin heavy chain, H.sub.N, derived botulinum toxin type A.

The third amino acid sequence region has therapeutic activity when it is released into the cytoplasm of a target cell or neuron. In one embodiment, the third amino acid sequence region of the polypeptide comprises a toxin light chain, L, derived from a neurotoxin selected from a group consisting of beratti toxin; butyricum toxin; tetani toxin; botulinum toxin types A, B, C.sub.1, D, E, F, and G. Preferably, the third amino acid sequence region of the polypeptide comprises a toxin light chain, L, derived from botulinum toxin type A.

In one embodiment, the polypeptide comprises a first amino acid sequence region derived from the H.sub.C of the tetani toxin, a second amino acid sequence region derived from the H.sub.N of botulinum toxin type B, and a third amino acid sequence region derived from the L chain of botulinum type A. In a preferred embodiment, the polypeptide comprises a first amino acid sequence region derived from the H.sub.C of the botulinum toxin type B, a second amino acid sequence region derived from the H.sub.N Of botulinum toxin type A, and a third amino acid sequence region derived from the L chain of botulinum type A. All other such combinations are included within the scope of the present invention.

In another embodiment, the polypeptide comprises a first amino acid sequence region derived from the H.sub.C of the botulinum toxin type A, wherein the amino acid sequence has at least one amino acid deleted, modified or replace; a second amino acid sequence region derived from the H.sub.N of botulinum toxin type A, and a third amino acid sequence region derived from the L chain of botulinum type A. All other such combinations are included within the scope of the present invention.

As indicated above, these polypeptides are single chains and may not be as potent as desired. To increase their potency, the third amino acid sequence region may be cleaved off by a proteolytic enzyme, for example a trypsin. The independent third amino acid sequence region may be reattached to the original polypeptide by a disulfide bridge. In one embodiment, the third amino acid sequence region is reattached the original polypeptide at the first amino acid sequence region. In a preferred embodiment, the third amino acid sequence region is reattached to the second amino acid sequence region.

If an unmodified neurotoxin is to be used to treat non-spasm related pain as described herein, the neurotoxin may be obtained by culturing an appropriate bacterial species. For example, botulinum toxin type A can be obtained by establishing and growing cultures of Clostridium botulinum in a fermenter and then harvesting and purifying the fermented mixture in accordance with known procedures. All the botulinum toxin serotypes are initially synthesized as inactive single chain proteins which must be cleaved or nicked by proteases to become neuroactive. The bacterial strains that make botulinum toxin serotypes A and G possess endogenous proteases and serotypes A and G can therefore be recovered from bacterial cultures in predominantly their active form. In contrast, botulinum toxin serotypes C.sub.1, D and E are synthesized by nonproteolytic strains and are therefore typically unactivated when recovered from culture. Serotypes B and F are produced by both proteolytic and nonproteolytic strains and therefore can be recovered in either the active or inactive form. However, even the proteolytic strains that produce, for example, the botulinum toxin type B serotype only cleave a portion of the toxin produced. The exact proportion of nicked to unnicked molecules depends on the length of incubation and the temperature of the culture. Therefore, a certain percentage of any preparation of, for example, the botulinum toxin type B toxin is likely to be inactive, possibly accounting for the known significantly lower potency of botulinum toxin type B as compared to botulinum toxin type A. The presence of inactive botulinum toxin molecules in a clinical preparation will contribute to the overall protein load of the preparation, which has been linked to increased antigenicity, without contributing to its clinical efficacy. Additionally, it is known that botulinum toxin type B has, upon intramuscular injection, a shorter duration of activity and is also less potent than botulinum toxin type A at the same dose level.

If a modified neurotoxin is to be used according to this invention to treat non-spasm related pain, recombinant techniques can be used to produce the desired neurotoxins. The technique includes steps of obtaining genetic materials from natural sources, or synthetic sources, which have codes for a neuronal binding moiety, an amino acid sequence effective to translocate the neurotoxin or a part thereof, and an amino acid sequence having therapeutic activity when released into a cytoplasm of a target cell, preferably a neuron. In a preferred embodiment, the genetic materials have codes for the H.sub.C, H.sub.N and L chain of the Clostridial neurotoxins, modified clostridial neurotoxins and fragments thereof. The genetic constructs are incorporated into host cells for amplification by first fusing the genetic constructs with a cloning vectors, such as phages or plasmids. Then the cloning vectors are inserted into hosts, preferably E. coli's. Following the expressions of the recombinant genes in host cells, the resultant proteins can be isolated using conventional techniques.

Although recombinant techniques are provided for the production modified neurotoxins, recombinant techniques may also be employed to produce non-modified neurotoxins, for example botulinum toxin A as it exists naturally, since the genetic sequence of botulinum toxin type A is known.

There are many advantages to producing these neurotoxins recombinantly. For example, production of neurotoxin from anaerobic Clostridium cultures is a cumbersome and time-consuming process including a multi-step purification protocol involving several protein precipitation steps and either prolonged and repeated crystallization of the toxin or several stages of column chromatography. Significantly, the high toxicity of the product dictates that the procedure must be performed under strict containment (BL-3). During the fermentation process, the folded single-chain neurotoxins are activated by endogenous clostridial proteases through a process termed nicking. This involves the removal of approximately 10 amino acid residues from the single-chain to create the dichain form in which the two chains remain covalently linked through the intrachain disulfide bond.

The nicked neurotoxin is much more active than the unnicked form. The amount and precise location of nicking varies with the serotypes of the bacteria producing the toxin. The differences in single-chain neurotoxin activation and, hence, the yield of nicked toxin, are due to variations in the type and amounts of proteolytic activity produced by a given strain. For example, greater than 99% of Clostridial botulinum type A single-chain neurotoxin is activated by the Hall A Clostridial botulinum strain, whereas type B and E strains produce toxins with lower amounts of activation (0 to 75% depending upon the fermentation time). Thus, the high toxicity of the mature neurotoxin plays a major part in the commercial manufacture of neurotoxins as therapeutic agents.

The degree of activation of engineered clostridial toxins is, therefore, an important consideration for manufacture of these materials. It would be a major advantage if neurotoxins such as botulinum toxin and tetanus toxin could be expressed, recombinantly, in high yield in rapidly-growing bacteria (such as heterologous E. coli cells) as relatively non-toxic single-chains (or single chains having reduced toxic activity) which are safe, easy to isolate and simple to convert to the fully-active form.

With safety being a prime concern, previous work has concentrated on the expression in E. coli and purification of individual H and L chains of tetanus and botulinum toxins; these isolated chains are, by themselves, non-toxic; see Li et al., Biochemistry 33:7014 7020 (1994); Zhou et al., Biochemistry 34:15175 15181 (1995), hereby incorporated by reference herein. Following the separate production of these peptide chains and under strictly controlled conditions the H and L chains can be combined by oxidative disulphide linkage to form the neuroparalytic di-chains.

It is known that post operative pain resulting from (i.e. secondary to) a muscle spasm can be alleviated by pre-operative injection of botulinum toxin type A. Developmental Medicine & Child Neurology 42;116 121:2000. Contrarily, our invention encompasses a method for treating postoperative pain by pre or peri-operative, peripheral administration of a botulinum toxin where the pain is not due to a spasmodic muscle.

Thus, a patient can either during surgery or up to about ten days prior to surgery (where the surgery is unrelated to correction of or treatment of a spasmodic muscle condition) be locally and peripherally administered by bolus injection with from about 20 units to about 300 units of a botulinum toxin, such a botulinum toxin type A, at or in the vicinity of the site of a prospective incision into the patient's dermis. The botulinum toxin injection can be subcutaneous or intramuscular. The surgery is not carried out to treat or to alleviate pain which results from a hyperactive or hypertonic muscle because we have surprisingly discovered that many types of pain which do not arise from or which do not result from a muscle spasm, can be significantly alleviated by practic of our disclosed invention.

According to our invention, for relief from post-operative pain, a patient who is scheduled for surgery for the purpose of tumor removal, bone graft, bone replacement, exploratory surgery, wound closure, a cosmetic surgery such as liposuction, or any of a myriad of other types of possible (non-muscle disorder treatment) surgical procedures which require one or more incisions into and/or through the patient's dermis can be treated, according to our invention, by peripheral administration of from about 0.01 U/kg to about 60 U/kg of a botulinum toxin, such as a botulinum toxin type A or B. The duration of significant post-operative pain alleviation can be from about 2 to about 6 months, or longer.

A method within the scope of the present invention can provide improved patient function. "Improved patient function" can be defined as an improvement measured by factors such as a reduced pain, reduced time spent in bed, increased ambulation, healthier attitude, more varied lifestyle and/or healing permitted by normal muscle tone. Improved patient function is synonymous with an improved quality of life (QOL). QOL can be assesses using, for example, the known SF-12 or SF-36 health survey scoring procedures. SF-36 assesses a patient's physical and mental health in the eight domains of physical functioning, role limitations due to physical problems, social functioning, bodily pain, general mental health, role limitations due to emotional problems, vitality, and general health perceptions. Scores obtained can be compared to published values available for various general and patient populations.
 

Claim 1 of 7 Claims

1. A method for treating post-operative incisional wound pain comprising administering a therapeutically effective amount of a botulinum toxin to an afflicted area of a patient, thereby alleviating the post-operative incisional wound pain, wherein the post-operative incisional wound pain is not associated with a muscle disorder.

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